JP7597607B2 - Filming tampering detection device, filming tampering detection system, and filming tampering detection program - Google Patents

Description

This disclosure relates to a photography tampering detection device.

For example, if the shooting lens is covered by an object, the imaging device cannot capture a normal image of the subject (hereinafter, the inability of the imaging device to capture a normal image of the subject is referred to as "shooting interference"). Therefore, the shooting interference detection device estimates whether or not the imaging device is being interfered with.

Patent Document 1 describes a photography tampering detection device that detects whether photography by a platform camera installed in an amusement park is being thwarted based on image information captured by the platform camera. The photography tampering detection device includes a photography tampering determination means that determines whether photography by the platform camera is being thwarted based on image information that indicates information that quantifies the amount of light that enters the platform camera. The photography tampering determination means determines a first state indicating that the platform camera may be thwarted when the numerical information indicated in the image information falls within a specific threshold range, and determines a second state that is more likely to indicate photography tampering than the first state when the first state continues for a predetermined period of time.

JP 2014-223135 A

In the conventional technology described above, the amount of light entering the imaging lens of the imaging device varies depending on the environment in which the imaging device is placed, so there is a problem in that the imaging device may be erroneously determined to be experiencing interference with photography even when the imaging device is not experiencing interference.

This disclosure has been made to solve the problems described above, and aims to provide a technology that improves the accuracy of determining whether or not an imaging device is being interfered with in capturing images.

The photography tampering detection device of the present disclosure includes an estimated information acquisition unit that acquires multiple pieces of interference estimation information indicating an estimation result of whether or not a corresponding imaging device among the multiple imaging devices is being interfered with in photography, and an interference identification unit that classifies the multiple imaging devices into multiple groups according to the illumination environment in which each imaging device is placed , and identifies whether or not a first imaging device is being interfered with in photography based on the interference estimation information corresponding to a first imaging device among the multiple imaging devices and the interference estimation information corresponding to a second imaging device among the multiple imaging devices that belongs to the same group as the first imaging device among the multiple imaging devices, among the multiple interference estimation information acquired by the estimated information acquisition unit.

This disclosure makes it possible to improve the accuracy of determining whether or not an imaging device is being obstructed from capturing images.

1 is a top view of the interior of a railway vehicle 10 in which a plurality of imaging devices of a photography tampering detection system according to a first embodiment are installed. 1 is a configuration diagram showing an example of a system configuration of a photography tampering detection system according to a first embodiment; 3A, 3B, 3C, and 3D are cross-sectional views showing examples of cross-sections at dotted lines Ya1-Ya2, Yb1-Yb2, Yc1-Yc2, and Yd1-Yd2, respectively, when looking at the inside of the railway vehicle 10 from the direction of arrow X in FIG. 1. FIG. 2 is a diagram showing an example of the range in which each of a plurality of imaging devices captures an image of the interior of a railway vehicle. 5A, 5B, 5C, and 5D are diagrams showing examples of image information obtained by capturing images using a plurality of imaging devices. 2 is a block diagram showing an example of a configuration of a main part of a photography tampering detection device in the photography tampering detection system according to the first embodiment; FIG. 7A and 7B are diagrams illustrating an example of a case where the interference identification unit identifies that a certain imaging device is not being interfered with in its photography, and FIG. 7B is a diagram illustrating an example of a case where the interference identification unit identifies that a certain imaging device is being interfered with in its photography. 2 is a diagram showing an example of the presence or absence of photography sabotage estimated for each of the four imaging devices shown in FIG. 1 and the presence or absence of photography sabotage identified by an interference identifying unit; FIG. 9A and 9B are diagrams illustrating an example of a hardware configuration of a photography tampering detection device in the photography tampering detection system according to the first embodiment. 10 is a flowchart illustrating an example of a process of a photography tampering detection device in the photography tampering detection system according to the first embodiment. 13 is a block diagram showing an example of a configuration of a main part of a photography tampering detection device in a photography tampering detection system according to a second embodiment. FIG. 13 is a flowchart illustrating an example of a process of a photography tampering detection device in a photography tampering detection system according to the second embodiment.

In order to explain the present disclosure in more detail, embodiments for carrying out the present disclosure will be described below with reference to the accompanying drawings.
Embodiment 1.
Fig. 1 is a top view of the interior of a railway vehicle 10 in which a plurality of imaging devices of a photography tampering detection system 1 according to embodiment 1 are installed. In embodiment 1, an example in which a plurality of imaging devices of a photography tampering detection system 1 according to embodiment 1 are installed inside the railway vehicle 10 as shown in Fig. 1 will be described, but the plurality of imaging devices of the photography tampering detection system 1 may be installed inside a vehicle other than a railway vehicle, inside a building, or the like, and is not limited to this example.

Figure 2 is a configuration diagram showing an example of the system configuration of the photography tampering detection system 1 according to the first embodiment. The photography tampering detection system 1 includes, as its main components, a railway vehicle 10, a plurality of imaging devices 11-1, 11-2, ..., 11-N (N is a natural number), a communication network 12, an image recording device 13, a display device 14, and a photography tampering detection device 100. Note that the photography tampering detection system 1 does not necessarily have to include the image recording device 13.

The multiple imaging devices 11-1, 11-2, ..., 11-N are, for example, digital still cameras or digital video cameras, and are capable of outputting image information obtained by shooting to the outside. The multiple imaging devices 11-1, 11-2, ..., 11-N are each installed inside the railway vehicle 10 and capture images of the interior of the railway vehicle 10. The multiple imaging devices 11-1, 11-2, ..., 11-N each output image information obtained by shooting to the outside via a communication network 12, such as a LAN (Local Area Network) or a wireless LAN.

In the example shown in Figures 1 and 2, only four imaging devices 11-1, 11-2, 11-3, and 11-4 are shown out of the multiple imaging devices 11-1, 11-2, ..., 11-N installed on the railway vehicle 10, and the configuration of the imaging devices of the photography tampering detection system 1 according to embodiment 1 will be described using the four imaging devices 11-1, 11-2, 11-3, and 11-4. Note that the number of imaging devices provided in the photography tampering detection system 1 may be more than one, and may be three or less, or five or more.

Figures 3A, 3B, 3C, and 3D are cross-sectional views showing examples of cross sections along dotted lines Ya1-Ya2, Yb1-Yb2, Yc1-Yc2, and Yd1-Yd2, respectively, when looking at the inside of the railway vehicle 10 from the direction of arrow X in Figure 1.

FIG. 4 is a diagram showing an example of the range in which each of the multiple image capturing devices 11-1, 11-2, 11-3, and 11-4 captures an image of the interior of the railway vehicle 10. In FIG.
5A, 5B, 5C, and 5D are diagrams showing examples of image information obtained by capturing images using the multiple image capturing devices 11-1, 11-2, 11-3, and 11-4, respectively.

As can be seen from Figures 3 to 5, the multiple imaging devices 11-1, 11-2, 11-3, and 11-4 are installed in a staggered arrangement above the doors through which passengers enter and exit when boarding and disembarking. This allows the multiple imaging devices 11-1, 11-2, 11-3, and 11-4 to capture the entire interior of the railway vehicle 10. Each of the multiple imaging devices 11-1, 11-2, 11-3, and 11-4 only needs to be able to capture the interior of the railway vehicle 10, and may be installed in a position other than above the doors through which passengers enter and disembark. The arrangement of the multiple imaging devices 11-1, 11-2, 11-3, and 11-4 may be arranged in a manner other than a staggered arrangement.

The image recording device 13 acquires each piece of image information output by the multiple imaging devices 11-1, 11-2, ..., 11-N, associates each piece of acquired image information with identification information for identifying the imaging devices 11-1, 11-2, ..., 11-N and acquisition time information indicating the time when the image was acquired, and records the information in a non-volatile storage medium or the like built into the image recording device 13. More specifically, for example, the image recording device 13 acquires each piece of image information output by the multiple imaging devices 11-1, 11-2, ..., 11-N via the communication network 12.

As long as the image recording device 13 can acquire the image information output by the multiple imaging devices 11-1, 11-2, ..., 11-N via the communication network 12, the location where the image recording device 13 is installed is not limited to inside the railway vehicle 10, and for example, the image recording device 13 may be installed in a location away from the railway vehicle 10. In the first embodiment, the image recording device 13 is described as being installed inside the railway vehicle 10.

As described below, the photography tampering detection device 100 determines whether or not each of the multiple imaging devices 11-1, 11-2, ..., 11-N is experiencing photography tampering based on multiple pieces of tampering estimation information each indicating an estimation result of whether or not a corresponding imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-N is experiencing photography tampering, and outputs an identification display signal for identifying the imaging device identified as experiencing photography tampering. Details will be described later.

The display device 14 displays the identification display signal output by the photography tampering detection device 100. The display device 14 is composed of, for example, a plurality of light-emitting elements corresponding to the plurality of imaging devices 11-1, 11-2, ..., 11-N, respectively. The light-emitting elements are, for example, light-emitting diodes or lamps. When the display device 14 is composed of a plurality of light-emitting elements, the photography tampering detection device 100 controls the light emission of each light-emitting element by outputting an identification display signal.

The display device 14 is not limited to a display device composed of multiple light-emitting elements. For example, the display device 14 may be a display such as a liquid crystal display. When the display device 14 is a display, the photography tampering detection device 100 outputs an image for identifying the imaging device identified as being subject to photography tampering as an identification display signal to the display, and controls the display of the display.

Alternatively, for example, the display device 14 may be an audio output device such as a speaker or a buzzer. When the display device 14 is an audio output device, the photography tampering detection device 100 performs notification control to notify by audio by outputting an identification display signal to the audio output device.

Alternatively, for example, the display device 14 may display an image signal output by an external device such as a computer (not shown). When the display device 14 displays an image signal output by an external device, the photography tampering detection device 100 outputs an identification signal for identifying the imaging device identified as being subject to photography tampering to the external device via the communication network 12, and the external device generates an image signal based on the identification signal acquired from the photography tampering detection device 100 and outputs the image signal to the display device 14.

In the first embodiment, as shown in FIG. 2, the display device 14 is configured with a number of light emitters 14-1, 14-2, 14-3, and 14-4 that correspond to the multiple imaging devices 11-1, 11-2, 11-3, and 11-4, respectively, arranged in the housing of the photography tampering detection device 100. The display device 14 controls the emission of each of the multiple light emitters 14-1, 14-2, 14-3, and 14-4 by the photography tampering detection device 100 outputting an identification display signal.

FIG. 6 is a block diagram showing an example of a configuration of a main part of the photography tampering detection device 100 in the photography tampering detection system 1 according to the first embodiment.
The photography tampering detection device 100 includes an estimated information acquisition unit 110 , an image acquisition unit 120 , an image brightness acquisition unit 130 , a reference brightness acquisition unit 140 , a tampering estimation unit 150 , a tampering identification unit 160 , and an output control unit 170 .

The image acquisition unit 120 acquires each piece of image information output by the multiple imaging devices 11-1, 11-2, ..., 11-N via the communication network 12. The image acquisition unit 120 may acquire each piece of image information output by the multiple imaging devices 11-1, 11-2, ..., 11-N and recorded by the image recording device 13 via the communication network 12 from the image recording device 13.

The image brightness acquisition unit 130 divides each image captured by the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple partial images, and acquires image brightness information indicating the brightness of each partial image in each of the images. More specifically, in the first embodiment, the image brightness acquisition unit 130 divides an image indicated by each piece of image information acquired by the image acquisition unit 120 into multiple partial images, and acquires image brightness information indicating the brightness of each partial image in the image indicated by each piece of image information.

More specifically, the image brightness acquisition unit 130 divides each image captured by the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple partial images, and calculates the average brightness of each partial image in each image to acquire image brightness information indicating the average brightness of each partial image in each image. Note that the "average brightness of each partial image" here means the average brightness of each partial image.

For example, the image brightness acquisition unit 130 may acquire image brightness information indicating the brightness of each partial image in each image captured by the multiple image capture devices 11-1, 11-2, ..., 11-N from the image capture devices 11-1, 11-2, ..., 11-N or the image recording device 13 via the communication network 12.

For example, the image brightness acquisition unit 130 divides each image captured by the multiple image capture devices 11-1, 11-2, ..., 11-N into two halves, an upper half and a lower half, and calculates the average brightness of the upper half of each image and the average brightness of the lower half of each image. Note that the image brightness acquisition unit 130 may divide each image captured by the multiple image capture devices 11-1, 11-2, ..., 11-N into three or more parts, and may divide the image so that each partial image has a different size.

The reason why the image brightness acquisition unit 130 calculates the brightness for each partial image is that when the multiple image capture devices 11-1, ..., 11-N are classified into multiple groups in advance as described below, in a group with low brightness, even if an image capture device is tampered with, the change in brightness is small, so there is a risk that the tampering may not be detected.

By having the image brightness acquisition unit 130 calculate the brightness for each partial image as described above, it is possible to reduce the possibility of failing to detect sabotage of photography, as described below, in cases where strong light falls on part of the image, such as when an emergency light is turned on in front of the imaging device.

The reference luminance acquisition section 140 acquires reference luminance information indicating predetermined reference luminances corresponding to the plurality of image capture devices 11-1, 11-2, . . . , 11-N.
For example, the reference luminance acquisition section 140 acquires reference luminance information from the multiple image capture devices 11-1, 11-2, . . . , 11-N or the image recording device 13 via the communication network 12.
The reference brightness acquisition unit 140 may acquire the reference brightness information by reading the reference brightness information from a storage device (not shown) provided inside or outside the housing of the photography tampering detection device 100 .

The interference estimation unit 150 compares the brightness of each partial image indicated by the image brightness information acquired by the image brightness acquisition unit 130 with the reference brightness indicated by the reference brightness information acquired by the reference brightness acquisition unit 140 for each imaging device. The interference estimation unit 150 generates a plurality of interference estimation information each indicating an estimation result of whether or not the corresponding imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N is being interfered with in the shooting by estimating for each imaging device through the comparison. More specifically, in the first embodiment, the interference estimation unit 150 generates interference estimation period information indicating the interference estimation period for an imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N that is estimated to be interfered with in the shooting by measuring the interference estimation period during which the imaging device is continuously estimated to be interfered with in the shooting. The interference estimation unit 150 outputs the generated interference estimation information and interference estimation period information to the estimation information acquisition unit 110.

For example, when estimating the presence or absence of filming interference, the interference estimation unit 150 may use the average value of the brightness in all images indicated by the image brightness information acquired by the image brightness acquisition unit 130, instead of the reference brightness indicated by the reference brightness information acquired by the reference brightness acquisition unit 140.

For example, if the lower half of the optical system, such as a lens, of any of the multiple imaging devices 11-1, 11-2, ..., 11-N is covered with a light-shielding cloth or the like, the brightness of each of the two partial images obtained by dividing an image captured by the imaging device into two parts, one above the other, will be higher than the reference brightness of the imaging device, and the brightness of the upper half partial image will be lower than the reference brightness of the imaging device. Therefore, the interference estimation unit 150 compares the brightness of each of the two partial images obtained by dividing an image into two parts, one above the other, with the reference brightness of the imaging device that captured the image, and if it determines that the brightness of the upper half partial image is higher than the reference brightness and the brightness of the lower half partial image is lower than the reference brightness, it generates interference estimation information indicating an estimated result that the imaging device is being interfered with, or interference estimation information indicating an estimated result that the lower half of the optical system of the imaging device is being interfered with.

Or, for example, the interference estimation unit 150 compares the luminance of each of two partial images obtained by dividing an image into upper and lower halves with the reference luminance of the imaging device that captured the image, and if it determines that the luminance of the upper half of the partial image is a value within a predetermined range centered on the reference luminance and the luminance of the lower half of the partial image is a value outside the predetermined range centered on the reference luminance, it generates interference estimation information indicating an estimated result that the imaging device is being interfered with in its imaging, or interference estimation information indicating an estimated result that the lower half of the optical system of the imaging device is being interfered with in its imaging.

In other words, the interference estimation unit 150 may generate interference estimation information indicating an estimation result of whether or not the imaging device is being partially interfered with in capturing an image by comparing the brightness of each partial image with a reference brightness.

Or, for example, if the optical system such as a lens in any of the multiple imaging devices 11-1, 11-2, ..., 11-N is entirely covered with a light-blocking cloth or the like, the luminance of each of the multiple partial images obtained by dividing an image captured by that imaging device will all be lower than the reference luminance of that imaging device. Therefore, for example, the interference estimation unit 150 compares the luminance of each of the multiple partial images obtained by dividing an image with the reference luminance of the imaging device that captured that image, and if it determines that all of the luminances are lower than the reference luminance, it generates interference estimation information indicating an estimated result that the imaging device is being interfered with, or interference estimation information indicating an estimated result that the entire optical system of that imaging device is being interfered with.

Or, for example, when the optical system of any of the multiple imaging devices 11-1, 11-2, ..., 11-N is irradiated with strong white light from the outside, the luminance of each of the multiple partial images obtained by dividing an image captured by that imaging device will all be higher than the reference luminance of that imaging device. Therefore, for example, the interference estimation unit 150 compares the luminance of each of the multiple partial images obtained by dividing an image with the reference luminance of the imaging device that captured that image, and when it determines that all of the luminances are higher than the reference luminance, it generates interference estimation information indicating an estimation result that the imaging device is being interfered with, or interference estimation information indicating an estimation result that the entire optical system of that imaging device is being interfered with.

Or, for example, the interference estimation unit 150 compares the luminance of each of multiple partial images obtained by dividing an image with the reference luminance of the imaging device that captured the image, and if it determines that all of the luminances are values within a predetermined range centered on the reference luminance, it generates interference estimation information indicating an estimation result that the imaging device is not being interfered with during imaging. On the other hand, if the interference estimation unit 150 determines that all of the luminances are values outside a predetermined range centered on the reference luminance, it generates interference estimation information indicating an estimation result that the imaging device is being interfered with during imaging, or interference estimation information indicating an estimation result that the entire optical system of the imaging device is being interfered with during imaging.

In other words, the interference estimation unit 150 may generate interference estimation information indicating an estimation result of whether or not the imaging device is being interfered with in its entirety by comparing the brightness of each partial image with a reference brightness.

In the first embodiment, as an example, the interference estimation unit 150 will be described as comparing the luminance of each of two partial images obtained by dividing an image into upper and lower halves with the reference luminance of the imaging device that captured the image, and if it determines that the luminance of the upper half of the partial image is higher than the reference luminance and the luminance of the lower half of the partial image is lower than the reference luminance, it will generate interference estimation information that indicates an estimation result that the lower half of the optical system of the imaging device is being interfered with in the capture of the image.

For example, even if the multiple imaging devices 11-1, 11-2, ..., 11-N and the image recording device 13 already installed are each unable to generate interference estimation information, the photography interference detection device 100 can generate interference estimation information by including the image acquisition unit 120, the image brightness acquisition unit 130, the reference brightness acquisition unit 140, and the interference estimation unit 150 as described above. Therefore, a photography interference detection system 1 can be constructed that uses interference estimation information.

The estimated information acquisition unit 110 acquires a plurality of pieces of interference estimated information each indicating an estimation result of whether or not a corresponding imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N is being interfered with during imaging. More specifically, in the first embodiment, the estimated information acquisition unit 110 acquires a plurality of pieces of interference estimated information generated by the interference estimation unit 150.

More specifically, in the first embodiment, the estimated information acquisition unit 110 further acquires, for an imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-N that is estimated to be subject to imaging interference, interference estimated period information indicating an estimated period during which the imaging device is continuously estimated to be subject to imaging interference. More specifically, in the first embodiment, the estimated information acquisition unit 110 further acquires interference estimated period information generated by the interference estimation unit 150. Alternatively, the estimated information acquisition unit 110 may acquire interference estimated period information by measuring the interference estimated period based on the multiple pieces of interference estimation information acquired. The estimated information acquisition unit 110 outputs the multiple pieces of interference estimation information acquired and the interference estimated period information to the interference identification unit 160.

The estimated information acquisition unit 110 may acquire the interference estimated information generated by the multiple imaging devices 11-1, 11-2, ..., 11-N from the multiple imaging devices 11-1, 11-2, ..., 11-N. In this case, the multiple imaging devices 11-1, 11-2, ..., 11-N estimate whether or not the multiple imaging devices 11-1, 11-2, ..., 11-N are being interfered with in the shooting by comparing the luminance of the multiple partial images obtained by dividing each captured image with a predetermined reference luminance corresponding to each imaging device 11-1, 11-2, ..., 11-N. Then, the multiple imaging devices 11-1, 11-2, ..., 11-N each generate interference estimated information indicating whether or not the imaging device is being interfered with in the shooting based on the estimation result. Then, the multiple imaging devices 11-1, 11-2, ..., 11-N each output the generated interference estimated information to the shooting interference detection device 100 via the communication network 12.
In this way, the processing load of the photography tampering detection device 100 can be reduced by each of the multiple imaging devices 11-1, 11-2, . . . , 11-N generating tampering estimation information.

Alternatively, the estimated information acquisition unit 110 may acquire the interference estimated information generated by the image recording device 13 from the image recording device 13. In this case, the image recording device 13 divides the image indicated by each piece of image information acquired from the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple partial images, and calculates the luminance of each partial image in the image indicated by each piece of image information. The image recording device 13 then generates interference estimated information by comparing the calculated luminance of each partial image with a predetermined reference luminance corresponding to each of the multiple imaging devices 11-1, 11-2, ..., 11-N. The image recording device 13 then outputs the generated interference estimated information to the photography interference detection device 100 via the communication network 12.

In this way, by having the image recording device 13 generate the interference estimation information, the processing load of the photography interference detection device 100 can be reduced. Furthermore, even if the multiple imaging devices 11-1, 11-2, ..., 11-N already installed are each unable to generate interference estimation information, the image recording device 13 can generate interference estimation information, thereby allowing the photography interference detection system 1 to be constructed using the interference estimation information.

When the estimated information acquisition unit 110 acquires tampering estimated information generated by multiple imaging devices 11-1, 11-2, ..., 11-N or the image recording device 13, the image acquisition unit 120, image brightness acquisition unit 130, reference brightness acquisition unit 140, and tampering estimation unit 150 are not essential components of the photography tampering detection device 100.

The interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple groups, and identifies whether or not the first imaging device is being interfered with in its photographing based on interference estimation information corresponding to the first imaging device among the multiple interference estimation information acquired by the estimation information acquisition unit 110, and interference estimation information corresponding to a second imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-N that belongs to the same group as the first imaging device. Note that the interference identification unit 160 may classify the multiple imaging devices 11-1, 11-2, ..., 11-N into a single group.

In more detail, in the first embodiment, when all of the interference estimation information acquired by the estimation information acquisition unit 110 corresponding to each imaging device of the set to which the first imaging device and the second imaging device belong indicates an estimation result that the corresponding imaging device is being interfered with in the course of imaging, the interference identification unit 160 identifies that none of the imaging devices is being interfered with in the course of imaging.

More specifically, for example, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a single group, and if it is estimated that the imaging device 11-1 is experiencing interference with photography, and if it is estimated that the imaging devices 11-2, ..., 11-N are all experiencing interference with photography, it identifies the imaging device 11-1 as not experiencing interference with photography.

This is because, for example, when a railway vehicle 10 equipped with multiple imaging devices 11-1, ..., 11-N enters a depot with all of its interior lights on, it is possible that the upper half of the images captured by each imaging device will appear bright due to the interior lights, and the lower half of the images will appear dark.

Alternatively, for example, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set and a second set, and if it is estimated that all of the multiple imaging devices 11-1 to 11-M (1 ≤ M ≤ N-1) belonging to the first set are experiencing interference with photography, it identifies the imaging device 11-1 as not experiencing interference with photography.

This is because, for example, when a railway vehicle 10 equipped with multiple imaging devices 11-1, ..., 11-N is entered into a depot with all interior lights in front of the multiple imaging devices 11-1 to 11-M (1≦M≦N-1) turned on and all interior lights in front of the other imaging devices turned off, the upper half of each image captured by the multiple imaging devices 11-1 to 11-M will appear bright due to the interior lights, the lower half of the image will appear dark, and the images captured by the other imaging devices will appear dark. Or, for example, when a railway vehicle 10 equipped with multiple imaging devices 11-1, ..., 11-N is entered into a depot with all interior lights turned off, the illuminance inside the entire railway vehicle is expected to be insufficient.

Regarding classification, for example, in the first embodiment, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including multiple imaging devices 11-1, 11-2, ..., 11-M (1 ≦ M ≦ N-1) and a second set including multiple imaging devices 11-K, ..., 11-N (K = M + 1). In this case, the interference identification unit 160 identifies whether or not the imaging device 11-1 is being interfered with in its photography based on each of the interference estimation information corresponding to the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set among the multiple pieces of interference estimation information, and identifies whether or not the imaging device 11-K is being interfered with in its photography based on each of the interference estimation information corresponding to the imaging devices 11-K, ..., 11-N belonging to the second set among the multiple pieces of interference estimation information.

For example, the interference identification unit 160 may classify the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple sets based on the current time. In this case, for example, when the current time corresponds to a daytime period, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple sets, and when the current time corresponds to a nighttime period, the interference identification unit 160 does not classify the multiple imaging devices 11-1, 11-2, ..., 11-N or classifies them into a single set. Note that the daytime period here is, for example, the period from sunrise to sunset. Also, the nighttime period here is, for example, the period from sunset to sunrise.

Alternatively, for example, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple sets based on the current position of the vehicle. In this case, for example, the interference identification unit 160 further classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple sets based on position influence information in which a position on the route along which the vehicle is traveling is associated with sunlight influence information indicating whether or not the multiple imaging devices 11-1, 11-2, ..., 11-N are affected by sunlight when capturing images at that position.

Alternatively, for example, the interference identification unit 160 may classify the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple sets based on the multiple interference estimation information acquired by the estimation information acquisition unit 110. In this case, for example, the interference identification unit 160 classifies the imaging devices corresponding to interference estimation information indicating an estimation result that the imaging device is being totally interfered with in the shooting of the imaging device, among the multiple interference estimation information acquired by the estimation information acquisition unit 110, into a first set. Also, for example, the interference identification unit 160 classifies the imaging devices corresponding to interference estimation information indicating an estimation result that the imaging device is being partially interfered with in the shooting of the imaging device, among the multiple interference estimation information acquired by the estimation information acquisition unit 110, into a second set.

More specifically, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N as follows, based on any of the above information or a predetermined classification criterion. For example, when some of the interior lights are turned on, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including imaging devices installed in front of the turned-on interior lights, and a second set including imaging devices not installed in front of the turned-on interior lights.

Or, for example, when external light is incident on the vehicle, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including imaging devices that are easily affected by external light, and a second set including imaging devices that are not easily affected by external light.

Or, for example, when imaging devices are installed in the vehicle passenger compartment and outside the vehicle passenger compartment (such as on a deck or connector), the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including imaging devices installed in the vehicle passenger compartment that capture areas where the brightness of the interior lighting is relatively high, and a second set including imaging devices installed outside the vehicle passenger compartment that capture areas where the brightness of the interior lighting is relatively low.

Or, for example, when imaging devices are installed to capture images inside and outside the vehicle (such as pantographs), the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including imaging devices that capture images inside the vehicle and are less susceptible to the effects of external light, and a second set including imaging devices that capture images outside the vehicle and are more susceptible to the effects of external light.

Or, for example, when the installation heights of multiple imaging devices are different, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including imaging devices installed at heights that are susceptible to interference with photography, and a second set of imaging devices installed at heights that are less susceptible to interference with photography.

More specifically, in the first embodiment, the interference identification unit 160 identifies whether or not the first imaging device is being interfered with in its imaging operation based on the interference estimation period indicated by the interference estimation period information further acquired by the estimation information acquisition unit 110.

For example, when it is estimated that a first imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M included in the first set is being interfered with in its photography, the interference identification unit 160 identifies whether or not the first imaging device is being interfered with in its photography based on interference estimation information indicating whether or not a second imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M included in the first set is being interfered with in its photography and the length of the interference estimation period during which it is continuously estimated that the first imaging device is being interfered with in its photography.

At the same time, for example, when it is estimated that the third imaging device among the multiple imaging devices 11-K, ..., 11-N included in the second set is being interfered with, the interference identification unit 160 identifies whether or not the third imaging device is being interfered with based on interference estimation information indicating whether or not the fourth imaging device among the multiple imaging devices 11-K, ..., 11-N included in the second set is being interfered with and the length of the interference estimation period during which it is continuously estimated that the third imaging device is being interfered with.

More specifically, for example, if there are four imaging devices 11-1, ..., 11-4, and the interference identification unit 160 defines the imaging devices 11-1 and 11-2 as a first set and the imaging devices 11-3 and 11-4 as a second set, the interference identification unit 160 will identify imaging device 11-1 as not being interfered with when it is estimated that only the lower half of the image of imaging device 11-1 is being interfered with, and when it is estimated that only the lower half of the image of imaging device 11-2 is being interfered with.

At the same time, for example, if it is estimated that the entire image of imaging device 11-3 is being interfered with, and also that the entire image of imaging device 11-4 is being interfered with, the interference identification unit 160 identifies imaging device 11-3 as not being interfered with.

This is because, for example, when a railway vehicle 10 equipped with multiple imaging devices 11-1, ..., 11-4 is entered into a depot with all interior lights in front of imaging device 11-1 and imaging device 11-2 turned on and all interior lights in front of the other imaging devices turned off, it is possible that the upper half of the images captured by imaging device 11-1 and imaging device 11-2 will appear bright due to the interior lights, and the lower half of the images will appear dark, resulting in the images captured by the other imaging devices appearing dark.

Alternatively, for example, when the estimated information acquisition unit 110 does not further acquire the interference estimated period information, the following configuration may be adopted. That is, when it is estimated that the imaging device 11-1 is being interfered with in the shooting and it is estimated that none of the imaging devices 11-2, ..., 11-N is being interfered with in the shooting, the interference identification unit 160 may measure the length of the interference estimated period during which the imaging device 11-1 is continuously estimated to be interfered with in the shooting, based on the interference estimation information corresponding to the imaging device 11-1. In this case, the interference identification unit 160 measures the interference estimated period from when it is first determined that the imaging device 11-1 is being interfered with in the shooting to when it is determined that the imaging device 11-1 is continuously estimated to be interfered with in the shooting, using, for example, a timer (not shown).

For example, if the length of the estimated interference period during which it is continuously estimated that the imaging device 11-1 is being interfered with in the course of imaging is shorter than a predetermined period, the interference identification unit 160 identifies that the imaging device 11-1 is not being interfered with in the course of imaging.

This is because it is anticipated that the optical system of the imaging device 11-1 may be temporarily covered if, for example, the optical system is inadvertently covered by the luggage of a passenger or the like aboard the railway vehicle 10.

The interference identifying unit 160 identifies the imaging device 11-1 as being subjected to interference with photography when the length of the estimated interference period during which it has been continuously estimated that the imaging device 11-1 is being interfered with is equal to or longer than a predetermined period.
This is because it is assumed that the optical system of the imaging device 11-1 is continuously covered.

For example, the interference identification unit 160 may classify the multiple imaging devices 11-1, ..., 11-N into multiple groups in advance, and measure the length of the interference estimation period during which it is continuously estimated that the imaging device is being interfered with in each group.

More specifically, when it is estimated that imaging device 11-1 of multiple imaging devices 11-1, 11-2, ..., 11-M (1≦M≦N-1) is experiencing interference with photography, the interference identification unit 160 measures, for example, using a timer not shown, the length of the interference estimation period during which imaging device 11-1 is continuously estimated to be experiencing interference, as the interference estimation period from when it is first determined that imaging device 11-1 is experiencing interference with photography to when it is determined that imaging device 11-1 is continuously estimated to be experiencing interference with photography. Furthermore, when it is estimated that the imaging device 11-K out of the multiple imaging devices 11-K, ..., 11-N (K = M + 1) is experiencing imaging interference, the interference identification unit 160 measures, for example, using a timer (not shown), the estimated interference period from when it was first determined that the imaging device 11-K was experiencing imaging interference to when it was determined that the imaging device 11-K was experiencing continuous imaging interference, as the length of the estimated interference period during which it was continuously determined that the imaging device 11-K was experiencing imaging interference.

The interference identification unit 160 determines that the imaging device 11-1 is not being interfered with in its photography if the length of the estimated interference period during which it has been continuously estimated that the imaging device 11-1 is being interfered with in its photography is shorter than a predetermined period. The interference identification unit 160 also determines that the imaging device 11-K is not being interfered with in its photography if the length of the estimated interference period during which it has been continuously estimated that the imaging device 11-K is being interfered with in its photography is shorter than a predetermined period.

This is because it is anticipated that the optical system of imaging device 11-1 may be temporarily covered in the event that the optical systems of imaging devices 11-1 and 11-K are covered by work by a worker aboard railway vehicle 10 for inspection, etc.

The interference identification unit 160 identifies the imaging device 11-1 as being subjected to interference with photography when the length of the interference estimation period during which it has been continuously estimated that the imaging device 11-1 is being interfered with is longer than a predetermined period. Also, the interference identification unit 160 identifies the imaging device 11-K as being subjected to interference with photography when the length of the interference estimation period during which it has been continuously estimated that the imaging device 11-K is being interfered with is longer than a predetermined period.
This is because it is assumed that the optical systems of the image capture devices 11-1 and 11-K are continuously covered.

The length of the interference estimated period that is determined when the interference identifying unit 160 identifies whether or not the imaging device 11-1 is being interfered with in photography will be described below with reference to FIG.
FIG. 7A is a diagram showing an example of a case where the interference identifying unit 160 identifies that a certain imaging device is not being interfered with in photography.
FIG. 7B is a diagram showing an example of a case where the interference identifying unit 160 identifies that a certain imaging device is being interfered with in its photographing.
7A and 7B, the horizontal axis indicates time, and the vertical axis indicates luminance. The solid broken line indicates the luminance in an image captured by a certain imaging device. The dashed straight line indicates the reference luminance of the imaging device.

As shown in FIG. 7A, when the luminance of an image captured by a certain imaging device is lower than the reference luminance of the imaging device, but is not continuously lower for a predetermined period of time, the interference identification unit 160 identifies that the imaging device is not being interfered with.

Also, as shown in FIG. 7B, if the luminance of an image captured by a certain imaging device is continuously lower than the reference luminance of the imaging device for a predetermined period of time, the interference identification unit 160 identifies the imaging device as being interfered with in its imaging operations.

A method in which the interference identifying unit 160 identifies the presence or absence of interference with photography based on the interference estimated information acquired by the estimated information acquiring unit 110 will be described below with reference to FIG.
FIG. 8 is a diagram showing an example of the presence or absence of photography interference estimated for each of the four imaging devices 11-1, 11-2, 11-3, and 11-4 shown in FIG.

At the time indicated by (1) in FIG. 8, it is estimated that none of the four image capture devices 11-1, 11-2, 11-3, and 11-4 is being interfered with in shooting.
Figure 8 shows an example in which, after the point indicated by (1), the estimated information acquisition unit 110 acquires each piece of interference estimation information corresponding to four imaging devices 11-1, 11-2, 11-3, and 11-4 every 15 minutes, and the interference identification unit 160 identifies whether or not there is interference with filming based on each piece of interference estimation information acquired by the estimated information acquisition unit 110.

At the time points indicated by (2) to (8) in FIG. 8, of the four imaging devices 11-1, 11-2, 11-3, and 11-4, it is estimated that imaging device 11-1 is experiencing imaging interference, and imaging devices other than imaging device 11-1 are not experiencing imaging interference.

Figure 8 shows an example in which the interference identification unit 160 identifies that the imaging device 11-1 is being interfered with in its imaging operation when it estimates that the imaging device 11-1 has been interfered with in its imaging operation for a period exceeding one hour, which is a predetermined period.

When the interference identification unit 160 identifies that the first imaging device is being interfered with, the output control unit 170 outputs an identification display signal for identifying the first imaging device identified as being interfered with.

More specifically, the output control unit 170 outputs an identification display signal for identifying an imaging device that the interference identification unit 160 has identified as being subject to interference with imaging among the imaging devices 11-1, 11-2, ..., 11-N. More specifically, for example, the output control unit 170 outputs the identification display signal to the display device 14.

For example, the output control unit 170 may output an identification display signal for identifying an imaging device that the interference identification unit 160 has identified as not being subjected to interference with photography among the imaging devices 11-1, 11-2, ..., 11-N.

For example, when the display device 14 is composed of a plurality of light-emitting elements 14-1, 14-2, 14-3, and 14-4 corresponding to a plurality of imaging devices 11-1, 11-2, 11-3, and 11-4, respectively, as shown in FIG. 2, the output control unit 170 performs output control so as to turn off the light-emitting element corresponding to the imaging device identified as not interfering with photography, and to turn on the light-emitting element corresponding to the imaging device identified as being interfering with photography.
The display device 14 displays the identification display signal output by the output control unit 170 .
The details of the identification display signal have been explained above in connection with the display device 14, and therefore will not be explained here.

9A and 9B are diagrams showing an example of a hardware configuration of the photography tampering detection device 100 in the photography tampering detection system 1 according to the first embodiment.
With reference to this figure, a hardware configuration of a main part of the photography tampering detection device 100 in the photography tampering detection system 1 according to the first embodiment will be described.

As shown in FIG. 9A, the photography tampering detection device 100 is configured by a computer, which has a processor 901 and a memory 902. The memory 902 stores programs for causing the computer to function as the estimated information acquisition unit 110, the image acquisition unit 120, the image brightness acquisition unit 130, the reference brightness acquisition unit 140, the interference estimation unit 150, the interference identification unit 160, and the output control unit 170. The functions of the estimated information acquisition unit 110, the image acquisition unit 120, the image brightness acquisition unit 130, the reference brightness acquisition unit 140, the interference estimation unit 150, the interference identification unit 160, and the output control unit 170 are realized by the processor 901 reading and executing the programs stored in the memory 902.

Also, as shown in FIG. 9B, the photography tampering detection device 100 may be configured with a processing circuit 903. In this case, the functions of the estimated information acquisition unit 110, the image acquisition unit 120, the image brightness acquisition unit 130, the reference brightness acquisition unit 140, the tampering estimation unit 150, the tampering identification unit 160, and the output control unit 170 may be realized by the processing circuit 903.

The photography tampering detection device 100 may also be configured with a processor 901, a memory 902, and a processing circuit 903 (not shown). In this case, some of the functions of the estimated information acquisition unit 110, the image acquisition unit 120, the image brightness acquisition unit 130, the reference brightness acquisition unit 140, the interference estimation unit 150, the interference identification unit 160, and the output control unit 170 may be realized by the processor 901 and the memory 902, and the remaining functions may be realized by the processing circuit 903.

The processor 901 may be, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a microprocessor, a microcontroller, or a DSP (Digital Signal Processor).

The memory 902 is, for example, a semiconductor memory or a magnetic disk. More specifically, the memory 902 is, for example, a random access memory (RAM), a read-only memory (ROM), a flash memory, an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a solid state drive (SSD), or a hard disk drive (HDD).

The processing circuit 903 is, for example, an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), an FPGA (Field-Programmable Gate Array), a SoC (System-on-a-Chip), or a system LSI (Large-Scale Integration).

The operation of the photography tampering detection device 100 in the photography tampering detection system 1 according to embodiment 1 will be described with reference to FIG. 10. FIG. 10 is a flowchart illustrating an example of the processing of the photography tampering detection device 100 in the photography tampering detection system 1 according to embodiment 1. Note that the photography tampering detection device 100 repeatedly executes the processing of the flowchart every predetermined time period, such as every 15 minutes, as in the example shown in FIG. 8.

As shown in FIG. 10, in step ST101, the reference luminance acquisition section 140 acquires reference luminance information indicating predetermined reference luminances corresponding to the plurality of image capture devices 11-1, 11-2, . . . , 11-N.
Next, in step ST102, the image acquisition section 120 acquires, via the communication network 12, each piece of image information output by the plurality of image capture devices 11-1, 11-2, . . . , 11-N.

Next, in step ST103, the image brightness acquisition unit 130 divides the image indicated by each piece of image information acquired by the image acquisition unit 120 into a plurality of partial images, and acquires image brightness information indicating the brightness of each partial image in the image indicated by each piece of image information. Also, in step ST103, the reference brightness acquisition unit 140 acquires reference brightness information indicating a predetermined reference brightness corresponding to each of the plurality of imaging devices.

Next, in step ST104, the interference estimation unit 150 generates multiple interference estimation information by estimating whether or not each of the multiple imaging devices 11-1, 11-2, ..., 11-N is being interfered with in the shooting of the imaging device by comparing the brightness of each partial image indicated by the image brightness information acquired by the image brightness acquisition unit 130 and the reference brightness indicated by the reference brightness information acquired by the reference brightness acquisition unit 140 for each imaging device. In addition, the interference estimation unit 150 generates interference estimation period information indicating the interference estimation period for an imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-N that is estimated to be interfered with in the shooting of the imaging device by measuring the interference estimation period during which the imaging device is continuously estimated to be interfered with in the shooting of the imaging device. The interference estimation unit 150 outputs the generated interference estimation information and interference estimation period information to the estimation information acquisition unit 110.

Next, in step ST105, the estimation information acquisition unit 110 acquires multiple pieces of interference estimation information generated by the interference estimation unit 150. Also, in step ST105, the estimation information acquisition unit 110 further acquires interference estimation period information generated by the interference estimation unit 150.

Next, in step ST110, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set and a second set. Here, the first set is made up of multiple imaging devices 11-1, 11-2, ..., 11-M (1 ≤ M ≤ N-1). Here, the second set is made up of multiple imaging devices 11-K, ..., 11-N (K = M + 1).

Next, in step ST111, the interference identification unit 160 determines whether or not it is estimated that at least one of the multiple imaging devices 11-1, 11-2, ..., 11-M is being interfered with in the shooting based on each interference estimation information corresponding to the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set among the multiple interference estimation information acquired by the estimation information acquisition unit 110. Also, in step ST111, the interference identification unit 160 determines whether or not it is estimated that at least one of the multiple imaging devices 11-K, ..., 11-N is being interfered with in the shooting based on each interference estimation information corresponding to the multiple imaging devices 11-K, ..., 11-N belonging to the second set among the multiple interference estimation information acquired by the estimation information acquisition unit 110.

If the interference identification unit 160 determines in step ST111 that none of the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first group are experiencing filming interference, then in step ST112, it identifies that none of the multiple imaging devices 11-1, 11-2, ..., 11-M are experiencing filming interference. After step ST112, in step ST113, the output control unit 170 outputs an identification display signal for identifying each of the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first group that the interference identification unit 160 has identified as not experiencing filming interference.

If the interference identification unit 160 determines in step ST111 that none of the multiple imaging devices 11-K, ..., 11-N belonging to the second set have been interfered with in shooting, then in step ST112 it identifies that none of the multiple imaging devices 11-K, ..., 11-N have been interfered with in shooting. After step ST112, in step ST113, the output control unit 170 outputs an identification display signal for identifying each of the multiple imaging devices 11-K, 11-2, ..., 11-N belonging to the second set that the interference identification unit 160 has identified as not being interfered with in shooting.

After step ST113, the photography tampering detection device 100 ends the processing of the flowchart, and the photography tampering detection device 100 repeatedly executes the processing of the flowchart every time a predetermined time has elapsed.

If, in step ST111, the interference identification unit 160 determines that at least one of the multiple imaging devices 11-1, 11-2, ..., 11-M (1≦M≦N-1) belonging to the first set is estimated to have been interfered with in the shooting of images, in step ST121, the interference identification unit 160 determines whether or not all of the multiple imaging devices 11-1, 11-2, ..., 11-M are estimated to have been interfered with in the shooting of images, based on each piece of interference estimation information corresponding to the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set, among the multiple pieces of interference estimation information acquired by the estimation information acquisition unit 110. Also, if in step ST111 the interference identification unit 160 determines that at least one of the multiple imaging devices 11-K, ..., 11-N (K = M + 1) belonging to the second set is estimated to have been interfered with in the shooting, in step ST121 the interference identification unit 160 determines whether or not all of the multiple imaging devices 11-K, ..., 11-N are estimated to have been interfered with in the shooting, based on each interference estimation information corresponding to the multiple imaging devices 11-K, ..., 11-N belonging to the second set, among the multiple interference estimation information acquired by the estimation information acquisition unit 110.

If the interference identification unit 160 determines in step ST121 that all of the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first group are estimated to be subject to interference with photography, the photography interference detection device 100 executes the process of step ST112. If the interference identification unit 160 determines in step ST121 that all of the multiple imaging devices 11-K, ..., 11-N belonging to the second group are estimated to be subject to interference with photography, the photography interference detection device 100 executes the process of step ST112.

If, in step ST121, the interference identification unit 160 determines that at least one of the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set is estimated to have not been interfered with in the shooting, in step ST131, the interference identification unit 160 determines whether or not the interference estimated period indicated by the interference estimated period information further acquired by the estimated information acquisition unit 110 exceeds a predetermined period for the imaging device estimated to have been interfered with in the shooting (the imaging device that the interference identification unit 160 has determined to have been interfered with in step ST111) among the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set.

In addition, if the interference identification unit 160 determines in step ST121 that at least one of the imaging devices 11-K, ..., 11-N belonging to the second set is estimated to have not been interfered with in the shooting, then in step ST131, the interference identification unit 160 determines whether or not the interference estimated period indicated by the interference estimated period information further acquired by the estimated information acquisition unit 110 exceeds a predetermined period for the imaging device estimated to have been interfered with in the shooting (the imaging device that the interference identification unit 160 determined in step ST111 to have been interfered with in the shooting) among the imaging devices 11-K, ..., 11-N belonging to the second set.

For an imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set that is estimated to be experiencing shooting interference (an imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be experiencing shooting interference), if the interference identification unit 160 determines in step ST131 that the estimated interference period indicated by the interference estimation period information further acquired by the estimated information acquisition unit 110 has not exceeded a predetermined period, then in step ST132, the interference identification unit 160 identifies that imaging device (an imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be experiencing shooting interference) is not experiencing shooting interference.

For an imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set that is estimated to be experiencing shooting interference (an imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be experiencing shooting interference), if the interference identification unit 160 determines in step ST131 that the estimated interference period indicated by the interference estimation period information further acquired by the estimated information acquisition unit 110 exceeds a predetermined period, then in step ST133, the interference identification unit 160 identifies the imaging device (the imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be experiencing shooting interference) as experiencing shooting interference.

Furthermore, with regard to an imaging device among the multiple imaging devices 11-K, ..., 11-N belonging to the second set that is estimated to have been interfered with in filming (an imaging device that the interference identification unit 160 has determined in step ST111 to have been interfered with in filming), if the interference identification unit 160 determines in step ST131 that the estimated interference period indicated by the interference estimation period information further acquired by the estimated information acquisition unit 110 does not exceed a predetermined period, then in step ST132, the interference identification unit 160 identifies that the imaging device (the imaging device that the interference identification unit 160 has determined in step ST111 to have been interfered with in filming) is not being interfered with in filming.

For an imaging device among the multiple imaging devices 11-K, ..., 11-N belonging to the second set that is estimated to be experiencing shooting interference (an imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be experiencing shooting interference), if the interference identification unit 160 determines in step ST131 that the estimated interference period indicated by the interference estimation period information further acquired by the estimated information acquisition unit 110 exceeds a predetermined period, then in step ST133, the interference identification unit 160 identifies the imaging device (the imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be experiencing shooting interference) as experiencing shooting interference.

After step ST132 or step ST133, in step ST134, for an imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set that is estimated not to have been interfered with in terms of photography (an imaging device that the interference identification unit 160 has determined to have been estimated not to have been interfered with in terms of photography in step ST111), the interference identification unit 160 identifies that the imaging device is not being interfered with in terms of photography.

After step ST132 or step ST133, in step ST134, for an imaging device among the multiple imaging devices 11-K, ..., 11-N belonging to the second set that is estimated to have not been interfered with in terms of photography (an imaging device that the interference identification unit 160 has determined to have not been interfered with in terms of photography in step ST111), the interference identification unit 160 identifies that the imaging device is not being interfered with in terms of photography.

After step ST134, in step ST135, the output control unit 170 outputs an identification display signal for identifying an imaging device that the interference identification unit 160 has identified as having been interfered with in the shooting of the imaging device, or an imaging device that the interference identification unit 160 has identified as not having been interfered with in the shooting of the imaging device.

After step ST135, the photography tampering detection device 100 ends the processing of the flowchart, and the photography tampering detection device 100 repeatedly executes the processing of the flowchart every time a predetermined time has elapsed.

The processing of step ST101 may be configured to be executed only the first time when the photography tampering detection device 100 repeatedly executes the processing of the flowchart every time a predetermined time has elapsed.

In addition, in step ST105, if the estimated information acquisition unit 110 is capable of acquiring interference estimated information from each of the multiple image capture devices 11-1, 11-2, ..., 11-N, or from an external device such as the image recording device 13, the processes from step ST101 to step ST104 are not essential processes.

In the present embodiment, the interference identification unit 160 has been described as classifying a plurality of imaging devices into two types of sets, i.e., a first set and a second set, but the interference identification unit 160 may classify a plurality of imaging devices into three or more types of sets.

The number of sets of imaging devices defined by the interference identification unit 160, or the combination of imaging devices belonging to each set among the multiple sets, may be dynamically changed according to the current time or the current location of the vehicle. More specifically, for example, when the vehicle is parked in a garage at night and there is little change in luminance in the images captured by the imaging devices, the interference identification unit 160 classifies the set of imaging devices into one type based on the current time. On the other hand, for example, when the vehicle is in commercial operation during the day and there is a large change in luminance in the images captured by the imaging devices, the interference identification unit 160 classifies the set of imaging devices into two or more types based on the current time.

Alternatively, for example, when a vehicle is parked in a garage with some of its emergency lights on, the interference identification unit 160 sets the set of imaging devices to two or more types based on the current location of the vehicle. On the other hand, when a vehicle is parked in a garage with all its emergency lights on or off, the interference identification unit 160 sets the set of imaging devices to one type based on the current location of the vehicle.

Alternatively, for example, when the vehicle is parked in the garage in conditions where direct sunlight is shining into the vehicle interior, such as early in the morning or evening, the interference identification unit 160 sets two or more types of sets of imaging devices based on the current time and the current location of the vehicle, and when the vehicle is parked in the garage in any other environment, the interference identification unit 160 sets one type of set of imaging devices based on the current time and the current location of the vehicle.

In the first embodiment, the image brightness acquisition unit 130 divides each image captured by a plurality of imaging devices into two partial images, acquires image brightness information indicating the brightness of each partial image in each image, and the interference estimation unit 150 generates interference estimation information based on the image brightness information. However, the interference estimation information of the present application is not limited to the interference estimation information.

For example, the image brightness acquisition unit 130 may divide the image into two parts, left and right, or may divide the image into two parts, top and bottom and left and right, so as to divide the image into a partial image in which the shooting range of the imaging device 11-1 and the shooting range of the imaging device 11-2 overlap and a partial image in which they do not overlap. In this case, the image brightness acquisition unit 130 may acquire image brightness information indicating the brightness of the left half and the right half of the image, or image brightness information indicating the brightness of the upper left, upper right, lower left, and lower right of the image, and the interference estimation unit 150 may generate interference estimation information based on the image brightness information.

By configuring as described above, the photography tampering detection device 100 can reduce the possibility of erroneously determining that a photography tampering has occurred when the photography tampering detection device is in a normal state when there is a bias in the brightness of each image captured by multiple photography devices, and can accurately determine whether or not the photography tampering detection device installed in a railway vehicle is in an abnormal photography state. Furthermore, by configuring as described above, the photography tampering detection device 100 can perform high-speed processing because the load on hardware such as the CPU is small compared to when determining the presence or absence of photography tampering based on image determination technology such as pattern matching that compares image features to determine the presence or absence of photography tampering based on the brightness of the image.

In addition, because the system is configured to calculate the brightness for each of the multiple partial images, it is possible to reduce the possibility of failing to detect an abnormal shooting condition in cases where strong light falls on part of the image, such as when an emergency light is turned on in front of the camera.

As described above, the photography tampering detection device 100 according to the first embodiment includes an estimated information acquisition unit 110 that acquires a plurality of pieces of tampering estimation information each indicating an estimation result of whether or not a corresponding imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N is being tampered with in photography, and an interference identification unit 160 that classifies the plurality of imaging devices 11-1, 11-2, ..., 11-N into a plurality of sets and identifies whether or not a first imaging device is being tampered with in photography based on interference estimation information corresponding to a first imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N and interference estimation information corresponding to a second imaging device that belongs to the same set as the first imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N, among the plurality of interference estimation information acquired by the estimated information acquisition unit 110.

According to the above configuration, whether or not the first imaging device is being interfered with is determined based not only on the interference estimation information corresponding to the first imaging device, but also on the interference estimation information corresponding to the second imaging device that belongs to the same group as the first imaging device. This improves the accuracy of determining whether or not the imaging device is being interfered with.

For example, when external light is incident on the vehicle while the vehicle is parked, or when the vehicle is parked with some of the interior lights turned on as emergency lights, the illuminance environment differs for each imaging device, causing a bias in the luminance of each image captured by the multiple imaging devices. Even in such a situation, the above-described configuration of the imaging tampering detection device 100 according to the first embodiment appropriately classifies the multiple imaging devices into multiple groups according to the illuminance environment in which the imaging devices are placed, thereby making it possible to identify whether or not the imaging devices are being tampered with in their imaging.

The tampering identifying section 160 in the photography tampering detection device 100 according to the first embodiment classifies the multiple image capture devices 11-1, 11-2, . . . , 11-N into multiple groups based on the current time.
According to the above configuration, the first imaging device and the second imaging device can be classified into the same group based on the current time. Therefore, it is possible to suitably determine whether the first imaging device is being sabotaged based on the interference estimation information corresponding to the first imaging device and the interference estimation information corresponding to the second imaging device. Therefore, it is possible to improve the accuracy of determining whether the imaging device is being sabotaged.

The tampering identification unit 160 in the photography tampering detection device 100 according to the first embodiment classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple groups when the current time falls within the daytime period, and does not classify the multiple imaging devices 11-1, 11-2, ..., 11-N when the current time falls within the nighttime period.

According to the above configuration, multiple imaging devices 11-1, 11-2, ..., 11-N are classified into multiple groups during the daytime, when the change in the illuminance environment for the imaging devices is greater than at night. This makes it possible to classify the imaging devices and determine whether or not there is any interference with photography based on the classification during the day, when there is a higher possibility than at night that an imaging device will be erroneously determined to be sabotaged even when it is not.

The multiple imaging devices 11-1, 11-2, ..., 11-N in the photography tampering detection device 100 according to the first embodiment are installed inside a vehicle, and the tampering identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple groups based on the current position of the vehicle.

According to the above configuration, the first imaging device and the second imaging device can be classified into the same group based on the current position of the vehicle. Therefore, it is possible to suitably determine whether the first imaging device is being obstructed from photographing based on the obstruction estimation information corresponding to the first imaging device and the obstruction estimation information corresponding to the second imaging device. Therefore, it is possible to improve the accuracy of determining whether the imaging device is being obstructed from photographing.

The hindrance identification unit 160 in the photography hindrance detection device 100 according to the first embodiment classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple groups based on position influence information that associates, for each position, a position on the route along which the vehicle is traveling with sunlight influence information indicating whether each of the multiple imaging devices 11-1, 11-2, ..., 11-N is affected by sunlight when capturing an image at that position.

According to the above configuration, for example, imaging devices that are affected by sunlight when capturing images can be classified into the same group. Therefore, for example, based on the interference estimation information corresponding to the first imaging device and the second imaging device that are affected by sunlight when capturing images, it is possible to suitably identify whether or not the first imaging device is being interfered with during imaging. Therefore, it is possible to improve the accuracy of determining whether or not an imaging device is being interfered with during imaging.

The hindrance identification unit 160 in the photography hindrance detection device 100 according to the first embodiment identifies that none of the imaging devices are hindranced when all of the hindrance estimation information corresponding to each imaging device in the group to which the first imaging device and the second imaging device belong, among the multiple pieces of hindrance estimation information acquired by the estimation information acquisition unit 110, indicate an estimation result that the corresponding imaging device is hindranced to photography.

According to the above configuration, in an unnatural situation where all of the imaging devices classified into the same group are presumed to be subject to shooting interference, it is possible to appropriately identify that none of the imaging devices are subject to shooting interference. Therefore, it is possible to improve the accuracy of determining whether or not an imaging device is subject to shooting interference.

The estimated information acquisition unit 110 in the photography tampering detection device 100 according to the first embodiment further acquires, for an imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-N that is estimated to be subject to photography tampering, estimated interference period information indicating an estimated period during which the imaging device is continuously estimated to be subject to photography tampering, and the interference identification unit 160 further identifies whether or not the first imaging device is subject to photography tampering based on the estimated interference period indicated by the estimated interference period information further acquired by the estimated information acquisition unit 110.

According to the above configuration, for example, it is possible to appropriately identify that the imaging device is being sabotaged in a situation where the imaging device is more likely to be sabotaged for continuous shooting than in a situation where the imaging device is sabotaged for temporary shooting. Therefore, it is possible to improve the accuracy of determining whether the imaging device is being sabotaged for shooting.

The photography interference detection device 100 according to the first embodiment further includes an image brightness acquisition unit 130 that divides each image captured by a plurality of imaging devices 11-1, 11-2, ..., 11-N into a plurality of partial images and acquires image brightness information indicating the brightness of each partial image in each image, a reference brightness acquisition unit 140 that acquires reference brightness information indicating a predetermined reference brightness corresponding to each of the plurality of imaging devices 11-1, 11-2, ..., 11-N, and an interference estimation unit 150 that generates a plurality of interference estimation information by estimating whether or not the imaging device is being interfered with in photography by comparing the brightness of each partial image indicated by the image brightness information acquired by the image brightness acquisition unit 130 and the reference brightness indicated by the reference brightness information acquired by the reference brightness acquisition unit 140 for each imaging device, and the estimation information acquisition unit 110 acquires the plurality of interference estimation information generated by the interference estimation unit 150.

According to the above configuration, even in a situation where an imaging device is partially obstructed from shooting, by comparing the luminance of each partial image with the reference luminance, it is possible to appropriately estimate for each imaging device whether or not the imaging device is being obstructed from shooting. Then, based on the multiple pieces of obstruction estimation information thus generated, it is possible to appropriately identify whether or not the imaging device is being obstructed from shooting. Therefore, it is possible to improve the accuracy of determining whether or not the imaging device is being obstructed from shooting.

Although not illustrated, the shooting interference detection device 100 may further include a shooting parameter acquisition unit and a reference shooting parameter acquisition unit. In this case, the shooting parameter acquisition unit acquires shooting parameter information indicating the shooting parameters used when each of the multiple imaging devices 11-1, 11-2, ..., 11-N captured an image. Examples of the shooting parameters here include ISO (International Organization for Standardization) sensitivity, shutter speed value, AE (Automatic Exposure) detection value, and AF (Autofocus) detection value. The reference shooting parameter acquisition unit acquires reference shooting parameter information indicating predetermined reference shooting parameters corresponding to each of the multiple imaging devices 11-1, 11-2, ..., 11-N. Examples of the predetermined reference shooting parameters here include values indicating the range of application of shooting parameters such as ISO sensitivity value, shutter speed value, aperture value, or autofocus detection value, which are used as a reference when each of the multiple imaging devices 11-1, 11-2, ..., 11-N captures an image. In addition, the above-mentioned interference estimation unit 150 may generate multiple interference estimation information by estimating whether or not the imaging device is being interfered with in shooting for each imaging device by comparing the shooting parameters indicated by the shooting parameter information acquired by the shooting parameter acquisition unit and the reference shooting parameters indicated by the reference shooting parameter information acquired by the reference shooting parameter acquisition unit for each imaging device. In addition, the above-mentioned estimation information acquisition unit 110 may acquire the multiple interference estimation information generated in this manner by the interference estimation unit 150. With the above configuration, it is also possible to appropriately estimate whether or not the imaging device is being interfered with in shooting.

Alternatively, although not illustrated, the photography tampering detection system 1 may further include a plurality of other imaging devices having the same functions as the plurality of imaging devices 11-1, 11-2, ..., 11-N, and a plurality of other photography tampering detection devices having the same functions as the photography tampering detection device 100. In that case, the above-mentioned estimated information acquisition unit 110 may further acquire a plurality of other tampering estimation information each indicating an estimation result of whether or not a corresponding imaging device among the plurality of other imaging devices is being tampered with from the other photography tampering detection device. Then, when the plurality of tampering estimation information (information on the imaging devices 11-1, 11-2, ..., 11-N) acquired by the estimated information acquisition unit 110 all indicate an estimation result that the corresponding imaging device is being tampered with, the above-mentioned tampering identification unit 160 may identify whether or not each of the plurality of imaging devices 11-1, 11-2, ..., 11-N is being tampered with based on the plurality of other tampering estimation information further acquired by the estimated information acquisition unit 110. For example, in such a configuration, multiple imaging devices 11-1, 11-2, ..., 11-N are installed in a first car connected to the train, and multiple other imaging devices are installed in a second car connected to the train. With the above configuration, it is possible to further improve the accuracy of determining whether or not the imaging devices are being obstructed from photographing.

Embodiment 2.
Hereinafter, the second embodiment will be described with reference to the drawings. Note that components having the same functions as those described in the first embodiment are given the same reference numerals, and the description thereof will be omitted.
11 is a block diagram showing an example of a configuration of a main part of a photography tampering detection device 100a in a photography tampering detection system 1a according to embodiment 2. The photography tampering detection device 100a according to embodiment 2 differs from the photography tampering detection device 100 according to embodiment 1 in that it includes a time mode switching unit 180 and a position mode switching unit 181 that are not included in the photography tampering detection device 100 according to embodiment 1.
The photography tampering detection device 100a in the photography tampering detection system 1a of embodiment 2 includes an estimated information acquisition unit 110, an image acquisition unit 120, an image brightness acquisition unit 130, a reference brightness acquisition unit 140, a tampering estimation unit 150, a tampering identification unit 160, an output control unit 170, a time mode switching unit 180, and a position mode switching unit 181.

The time mode switching unit 180 switches the operation mode of the photography tampering detection device 100a based on the current time to either a tampering detection mode in which each of the multiple imaging devices detects whether photography is being tampered with, or a tampering detection pause mode in which tampering detection that detects whether each of the multiple imaging devices is being tampered with is paused.

For example, when the time mode switching unit 180 switches the operation mode of the photography tampering detection device 100a to the tampering detection mode, the above-mentioned estimated information acquisition unit 110 acquires multiple pieces of tampering estimated information, and the above-mentioned tampering identification unit 160 identifies whether or not the first imaging device is being tampered with in photography using the above-mentioned method.

More specifically, in the first embodiment, the time mode switching unit 180 switches the operation mode of the photography tampering detection device 100a to the tampering detection pause mode when the current time corresponds to the daytime, and switches the operation mode of the photography tampering detection device 100a to the tampering detection mode when the current time corresponds to the nighttime.

More specifically, the time mode switching unit 180 switches between two operating modes based on time information indicating the current time: a tampering detection mode that detects whether or not there is tampering with photography for each of the multiple imaging devices 11-1, 11-2, ..., 11-N, and a detection pause mode that does not detect whether or not there is tampering with photography for each of the multiple imaging devices 11-1, 11-2, ..., 11-N.

More specifically, for example, the time mode switching unit 180 switches the operation mode so that each of the multiple imaging devices 11-1, 11-2, ..., 11-N operates in the detection pause mode during the time period during which each of the multiple imaging devices 11-1, 11-2, ..., 11-N is affected by sunlight when capturing images, based on time period information in which the time period is predetermined and time information indicating the current time. The operation mode is switched so that each of the multiple imaging devices 11-1, 11-2, ..., 11-N operates in the tampering detection mode during the time period during which each of the multiple imaging devices 11-1, 11-2, ..., 11-N is not affected by sunlight when capturing images.

More specifically, for example, the time mode switching unit 180 switches the operation mode so that each of the multiple imaging devices 11-1, 11-2, ..., 11-N operates in the detection pause mode during daytime hours when the imaging devices are affected by sunlight, and switches the operation mode so that each of the multiple imaging devices 11-1, 11-2, ..., 11-N operates in the tampering detection mode during nighttime hours when the imaging devices are not affected by sunlight.

The time information is obtained, for example, using a clock function (not shown) provided in the photography tampering detection device 100a. The clock function is similar to the clock function provided in an electronic device such as a publicly known general-purpose computer, for example, and is a publicly known technology, so a detailed description is omitted.

The time zone information is, for example, stored in advance in the time mode switching unit 180. Alternatively, for example, the time zone information may be acquired by the time mode switching unit 180 from a storage device (not shown) provided inside or outside the housing of the photography tampering detection device 100a, or from an external device such as the image recording device 13 via the communication network 12.

In this way, by including the time mode switching unit 180, the photography tampering detection device 100a detects the presence or absence of photography tampering for each of the multiple imaging devices 11-1, 11-2, ..., 11-N during a time period when each of the multiple imaging devices 11-1, 11-2, ..., 11-N is not affected by sunlight when taking pictures, thereby reducing false detections.

The position mode switching unit 181 switches the operation mode of the photography tampering detection device based on the current position of the vehicle to either a tampering detection mode that detects whether or not each of the multiple imaging devices is being tampered with, or a tampering detection pause mode that pauses tampering detection that detects whether or not each of the multiple imaging devices is being tampered with.

When the position mode switching unit 181 switches the operation mode of the photography tampering detection device 100a to the tampering detection mode, the above-mentioned estimated information acquisition unit 110 acquires multiple pieces of tampering estimated information, and the tampering identification unit 160 identifies whether or not the first imaging device is being tampered with in photography using the above-mentioned method.

More specifically, the position mode switching unit 181 determines whether the current position is a position where the multiple imaging devices are affected by sunlight when they each capture an image, based on the position influence information in which a position on the route on which the vehicle travels is associated with sunlight influence information indicating whether the multiple imaging devices are affected by sunlight when they each capture an image at that position. If the interference identification unit 160 determines that the current position is a position where the multiple imaging devices are affected by sunlight when they each capture an image, it switches the operation mode of the photography interference detection device 100a to interference detection pause mode. If the interference identification unit 160 determines that the current position is not a position where the multiple imaging devices are affected by sunlight when they each capture an image, it switches the operation mode of the photography interference detection device 100a to interference detection mode.

More specifically, the position mode switching unit 181 switches between two operating modes based on position information indicating the position where the railway vehicle 10 is traveling: a hindrance detection mode that detects whether or not there is hindrance to photography for each of the multiple imaging devices 11-1, 11-2, ..., 11-N, and a detection pause mode that does not detect whether or not there is hindrance to photography for each of the multiple imaging devices 11-1, 11-2, ..., 11-N.

More specifically, for example, the position mode switching unit 181 switches the operation mode to operate in the detection pause mode when the railway vehicle 10 travels through a position where the multiple imaging devices 11-1, 11-2, ..., 11-N are affected by sunlight when taking pictures, based on information about the current position and position influence information in which information indicating each of multiple positions on the route along which the railway vehicle 10 travels is previously associated with sunlight influence information indicating the presence or absence of sunlight influence when each of the multiple imaging devices 11-1, 11-2, ..., 11-N takes pictures, and switches the operation mode to operate in the interference detection mode when the railway vehicle 10 travels through a position where the multiple imaging devices 11-1, 11-2, ..., 11-N are not affected by sunlight when taking pictures.

More specifically, for example, the position mode switching unit 181 switches the operation mode to operate in the detection pause mode when the railway vehicle 10 travels above ground where the multiple imaging devices 11-1, 11-2, ..., 11-N are affected by sunlight when capturing images, and switches the operation mode to operate in the interference detection mode when the railway vehicle 10 travels underground where the multiple imaging devices 11-1, 11-2, ..., 11-N are not affected by sunlight when capturing images.

The position information is obtained, for example, using a running position detection function (not shown) provided on the railcar 10 or a train to which the railcar 10 is coupled. The running position detection function detects the position of the railcar 10 by using a Global Navigation Satellite System (GNSS) such as the Global Positioning System (GPS). The method of detecting the position using the GNSS is publicly known, so a detailed description will be omitted.

The position impact information is, for example, stored in advance in the position mode switching unit 181. Alternatively, for example, the position impact information may be acquired by the position mode switching unit 181 from a storage device (not shown) provided inside or outside the housing of the photography tampering detection device 100a, or from an external device such as the image recording device 13 via the communication network 12.

In this way, by including the position mode switching unit 181, the photography tampering detection device 100a detects the presence or absence of photography tampering for each of the multiple imaging devices 11-1, 11-2, ..., 11-N at a position that is not affected by sunlight when each of the multiple imaging devices 11-1, 11-2, ..., 11-N takes pictures, thereby reducing false detections.

The photography tampering detection device 100a may be equipped with either the time mode switching unit 180 or the position mode switching unit 181, or may be equipped with both the time mode switching unit 180 and the position mode switching unit 181.

For example, if the photography tampering detection device 100a is equipped with both the time mode switching unit 180 and the position mode switching unit 181, the photography tampering detection device 100a may operate in the tampering detection mode during a time period in which the operation mode is set to the tampering detection mode by the time mode switching unit 180, and may operate in the tampering detection mode only at positions in which the operation mode is set to the tampering detection mode by the position mode switching unit 181 during a time period in which the operation mode is set to the detection pause mode by the time mode switching unit 180.

The hardware configuration of the main parts of the photography tampering detection device 100a is the same as that described with reference to Figures 9A and 9B in embodiment 1, and therefore will not be illustrated or described. That is, the functions of the estimated information acquisition unit 110, image acquisition unit 120, image brightness acquisition unit 130, reference brightness acquisition unit 140, tampering estimation unit 150, tampering identification unit 160, output control unit 170, time mode switching unit 180, and position mode switching unit 181 may be realized by the processor 901 and memory 902, or may be realized by the processing circuit 903.

Figure 12 is a flowchart illustrating an example of the processing of the photography tampering detection device 100a in the photography tampering detection system 1a according to embodiment 2. The processing of the photography tampering detection device 100a in the photography tampering detection system 1a according to embodiment 2 will be described with reference to the figure.

The photography tampering detection device 100a repeatedly executes the process of the flowchart shown in FIG. 12 as a pre-stage process of the process of the flowchart shown in FIG. 10, and the photography tampering detection system 1a executes the process of the flowchart shown in FIG. 10 only when the operation mode is the tampering detection mode.

First, in step ST1201, the time mode switching section 180 determines whether or not the current time is in a time zone affected by sunlight.
If, in step ST1201, the time mode switching section 180 determines that the current time is not in a time period affected by sunlight, in step ST1202, the time mode switching section 180 switches the operation mode to the tampering detection mode.

After step ST1202, the photographing tampering detection device 100a ends the process of the flowchart, and repeats the process of the flowchart.
If, in step ST1201, the time mode switching section 180 determines that the current time is in a time period affected by sunlight, in step ST1203, the time mode switching section 180 switches the operation mode to the detection pause mode.

After step ST1203, in step ST1204, the position mode switching unit 181 determines whether or not the position in which the railway vehicle 10 is traveling is a position that is affected by sunlight.
In step ST1204, if the position mode switching unit 181 determines that the position in which the railway vehicle 10 is traveling is a position that is affected by sunlight, the photography tampering detection device 100a terminates the processing of the flowchart, and the photography tampering detection device 100a repeatedly executes the processing of the flowchart.

If, in step ST1204, the position mode switching unit 181 determines that the position in which the railway vehicle 10 is traveling is not a position that is affected by sunlight, in step ST1205, the position mode switching unit 181 switches the operation mode to the interference detection mode.
After step ST1205, the photographing tampering detection device 100a ends the process of the flowchart, and repeats the process of the flowchart.

By configuring it as described above, the photography tampering detection device 100a can accurately determine whether or not the imaging devices installed inside the railway vehicle are in an abnormal photography state. Furthermore, by configuring it in this way, the photography tampering detection device 100a can suppress false detections because it detects the presence or absence of photography tampering for each of the multiple imaging devices 11-1, 11-2, ..., 11-N during a time period when each of the multiple imaging devices 11-1, 11-2, ..., 11-N is not affected by sunlight when taking pictures.

The photographing tampering detection device 100 or the photographing tampering detection device 100a may detect the presence or absence of photographing tampering by using photographing parameters at the time of photographing an image, such as the color tone or focus of the image, instead of the brightness of the image. Furthermore, the photographing tampering detection device 100 or the photographing tampering detection device 100a is not limited to application to the railroad car 10, but can also be applied to vehicles such as large passenger buses or buildings such as houses.
It should be noted that the embodiments may be freely combined, any of the components in each embodiment may be modified, or any of the components in each embodiment may be omitted.

The photography tampering detection device according to the present disclosure can be applied to a photography tampering detection system. In addition, the photography tampering detection device according to the present disclosure can be applied not only to railway cars, but also to vehicles such as large passenger buses, or buildings such as houses.

1, 1a, 1b, 1c Photography tampering detection system, 10, 10-1, ..., 10-m, ..., 10-M Railway vehicle, 11-1, 11-2, ..., 11-N, 11-1-1, 11-2-1, ..., 11-N-1, 11-1-m, 11-2-m, ..., 11-N-m, 11-1-M, 11-2-M, ..., 11-N-M Imaging device, 12 Communication network, 13 Image recording device, 14 Display device, 14-1, 14-2, 14-3, 14-4 Light emitter, 100, 100a, 100b, 100b-1, 100b-2, ..., 100b-M, 100c Photography tampering detection device, 110 Estimated information acquisition unit, 111 Photography parameter estimated information acquisition unit, 120 Image acquisition unit, 130 image brightness acquisition unit, 131 shooting parameter acquisition unit, 140 reference brightness acquisition unit, 141 reference shooting parameter acquisition unit, 150 interference estimation unit, 151 shooting parameter interference estimation unit, 160, 160b, 160c interference identification unit, 170 output control unit, 180 time mode switching unit, 181 position mode switching unit, 901 processor, 902 memory, 903 processing circuit.

Claims (18)

an estimation information acquisition unit for acquiring a plurality of pieces of interference estimation information each indicating an estimation result of whether or not a corresponding one of the plurality of imaging devices is being interfered with in photography;
a disturbance identification unit that classifies the plurality of imaging devices into a plurality of groups according to the illumination environment in which each imaging device is placed , and identifies whether or not the first imaging device is being disturbed in photography based on disturbance estimation information corresponding to a first imaging device among the plurality of imaging devices and disturbance estimation information corresponding to a second imaging device among the plurality of imaging devices that belongs to the same group as the first imaging device, among the plurality of disturbance estimation information acquired by the estimated information acquisition unit. The photography tampering detection device according to claim 1, characterized in that the tampering identification unit classifies the multiple imaging devices into multiple groups based on the current time. The photography tampering detection device according to claim 2, characterized in that the tampering identification unit classifies the multiple imaging devices into multiple groups when the current time corresponds to a daytime period, and does not classify the multiple imaging devices when the current time corresponds to a nighttime period. The plurality of imaging devices are installed in a vehicle,
The photography tampering detection device according to claim 1 , wherein the tampering identification unit classifies the plurality of imaging devices into a plurality of groups based on a current position of the vehicle. The photography tampering detection device according to claim 4, characterized in that the tampering identification unit classifies the multiple imaging devices into multiple groups based on position influence information in which a position on the route on which the vehicle travels is associated with sunlight influence information indicating whether the multiple imaging devices are affected by sunlight when capturing images at that position. The photography tampering detection device according to any one of claims 1 to 5, characterized in that, when all of the pieces of tampering estimation information acquired by the estimation information acquisition unit, which correspond to each imaging device of the set to which the first imaging device and the second imaging device belong, indicate an estimation result that the corresponding imaging device is being tampered with, the tampering identification unit identifies that none of the imaging devices is being tampered with. the estimated information acquisition unit further acquires, for an imaging device among the plurality of imaging devices that is estimated to be subject to imaging interference, estimated interference period information indicating an estimated interference period during which the imaging device is continuously estimated to be subject to imaging interference;
The photographing tampering detection device according to any one of claims 1 to 6, characterized in that the interference identification unit determines whether or not the first imaging device is being interfered with in photographing based further on the interference estimated period indicated by the interference estimated period information further acquired by the estimated information acquisition unit. an image luminance acquisition unit that divides each image captured by the plurality of image capture devices into a plurality of partial images and acquires image luminance information indicating luminance of each partial image in each of the images;
a reference luminance acquisition unit that acquires reference luminance information indicating a predetermined reference luminance corresponding to each of the plurality of imaging devices;
a disturbance estimation unit that generates the plurality of disturbance estimation information by estimating, for each imaging device, whether or not the imaging device is being disturbed in shooting by comparing, for each imaging device, the luminance of each partial image indicated by the image luminance information acquired by the image luminance acquisition unit and the reference luminance indicated by the reference luminance information acquired by the reference luminance acquisition unit,
The photography tampering detection device according to claim 1 , wherein the estimated information acquisition unit acquires a plurality of pieces of tampering estimated information generated by the tampering estimation unit. an imaging parameter acquisition unit that acquires imaging parameter information indicating imaging parameters used when each of the plurality of imaging devices captured an image;
a reference shooting parameter acquisition unit that acquires reference shooting parameter information indicating predetermined reference shooting parameters corresponding to each of the plurality of image capture devices;
a disturbance estimation unit that generates the plurality of disturbance estimation information by estimating whether or not the imaging device is disturbed in shooting by comparing, for each imaging device, the imaging parameters indicated by the imaging parameter information acquired by the imaging parameter acquisition unit and the reference imaging parameters indicated by the reference imaging parameter information acquired by the reference imaging parameter acquisition unit,
9. The photographing tampering detection device according to claim 1, wherein the estimated information acquisition unit acquires a plurality of pieces of tampering estimated information generated by the tampering estimation unit. A time mode switching unit is further provided for switching an operation mode of the photographing tampering detection device to either a tampering detection mode for detecting whether or not each of the plurality of image capture devices is being tampered with, or a tampering detection pause mode for pausing the tampering detection for detecting whether or not each of the plurality of image capture devices is being tampered with, based on a current time;
The photographing tampering detection device according to any one of claims 1 to 9, characterized in that, when the time mode switching unit switches the operating mode to the tampering detection mode, the estimated information acquisition unit acquires the multiple pieces of tampering estimated information, and the tampering identification unit identifies whether or not the first imaging device is being tampered with during photographing. The time mode switching unit is
If the current time corresponds to a daytime time zone, switching the operation mode to the tamper detection pause mode;
11. The photographing tampering detection device according to claim 10, wherein the operation mode is switched to the tampering detection mode when the current time corresponds to a nighttime period. The plurality of imaging devices are installed in a vehicle,
A position mode switching unit is further provided which switches an operation mode of the photography tampering detection device to either a tampering detection mode in which the plurality of imaging devices detect whether or not photography is being tampered with, or a tampering detection pause mode in which the tampering detection for detecting whether or not photography is being tampered with, based on a current position of the vehicle,
The photographing tampering detection device according to any one of claims 1 to 11, characterized in that, when the position mode switching unit switches the operation mode to the interference detection mode, the estimated information acquisition unit acquires the plurality of pieces of interference estimated information, and the interference identification unit identifies whether or not the first imaging device is being interfered with in photographing. The position mode switching unit is
determining whether the current position is a position that will be affected by sunlight when each of the plurality of image capturing devices captures an image, based on position influence information in which a position on a route along which the vehicle travels is associated with sunlight influence information indicating whether or not each of the plurality of image capturing devices is affected by sunlight at that position;
when it is determined that the current location is a location where the plurality of imaging devices are affected by sunlight when capturing images, the operation mode is switched to the interference detection pause mode;
The photographing interference detection device according to claim 12, characterized in that, when it is determined that the current location is not a location where the multiple imaging devices are affected by sunlight when taking images, the operation mode is switched to the interference detection mode. The estimated information acquisition unit further acquires, from another photography tampering detection device, another plurality of pieces of tampering estimated information each indicating an estimated result of whether or not a corresponding imaging device among another plurality of imaging devices is being tampered with for photography;
The photography tampering detection device according to any one of claims 1 to 13, characterized in that when all of the multiple pieces of interference estimation information acquired by the estimated information acquisition unit indicate an estimation result that the corresponding imaging device is being tampered with during photography, the interference identification unit determines whether or not each of the multiple imaging devices is being tampered with during photography based on another multiple pieces of interference estimation information further acquired by the estimated information acquisition unit. The plurality of imaging devices are installed in a first car coupled to a train set,
15. The photography tampering detection device according to claim 14, wherein the other plurality of imaging devices are installed in a second car connected to the train set. The photography tampering detection device according to any one of claims 1 to 15, further comprising an output control unit that outputs an identification display signal for identifying the first imaging device identified as being subject to photography tampering when the tampering identification unit identifies the first imaging device as being subject to photography tampering. The photography tampering detection device according to claim 16,
The plurality of imaging devices;
A photography tampering detection system comprising: a display device that displays the identification display signal output by the output control unit. a photography interference detection program for causing a computer to function as an interference identification unit that classifies the multiple imaging devices into multiple groups according to the illumination environment in which each imaging device is placed, and identifies whether or not a first imaging device is being interfered with in photography based on interference estimation information corresponding to a first imaging device among the multiple imaging devices and interference estimation information corresponding to a second imaging device among the multiple imaging devices that belongs to the same group as the first imaging device, among the multiple interference estimation information acquired by the estimated information acquisition unit.

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