JP6759028B2 - Imaging device and its control method, program - Google Patents

Description

The present invention relates to an imaging device or the like capable of imaging with invisible light.

Conventionally, as an imaging device for monitoring at night or in a dark place, a surveillance camera equipped with an infrared illumination device that irradiates infrared light which is invisible light is known. This camera has the advantage of being able to monitor without being noticed by people even in the absence of visible light by turning on infrared illumination. In recent years, there has been an increasing demand for surveillance cameras equipped with an infrared illumination device with increased illumination intensity in order to enable monitoring of a distant subject.

There are also surveillance cameras equipped with infrared illumination and visible illumination. Shooting under infrared illumination is unnoticed by people, but has the disadvantage that it is difficult to distinguish the characteristics of a person. Further, while shooting under visible lighting is noticed by a person, it has an advantage that it is easy to distinguish the characteristics of the person. Therefore, Patent Document 1 proposes a method of reliably photographing an intruder with a single light emission of visible illumination while photographing with infrared illumination so as not to be noticed by humans.

Japanese Unexamined Patent Publication No. 2001-275021 Japanese Unexamined Patent Publication No. 2012-11840

However, looking directly at infrared illumination for a long time may pose a risk to the human body (especially the eyes). That is, when an infrared light source for illuminating a subject is turned on, if a person enters the irradiation range of infrared light from outside the angle of view of imaging, there is a concern that the human body may be adversely affected. In particular, since infrared light cannot be visually recognized, there is a risk that strong infrared light may be radiated to the eyes for a long time without being noticed.

By the way, if the lighting is too strong, it may cause discomfort such as glare. Therefore, Patent Document 2 proposes a method of adjusting the lighting intensity according to the distance to the subject. However, in the case of distant monitoring with infrared illumination, if the intensity of infrared light is adjusted by applying the technique of Patent Document 2, the irradiation intensity is appropriate in the near field when the subject appears in the near field. It is adjusted (low) so that Then, the illumination intensity to a distant place decreases, and it becomes difficult to monitor the distant place. That is, when the subject appears in the near field or the like, it becomes difficult to appropriately continue the monitoring using infrared light while considering the suppression of the risk to the human body.

An object of the present invention is to suppress the influence on the eyes while ensuring the monitoring function.

To accomplish the above object, an imaging capable capturing means the photographic material by invisible light, wherein the first irradiating means for irradiating the invisible light, the invisible by the first irradiation means in parallel with the irradiation of light, and a second irradiating means for irradiating the visible light, and detecting means for detecting a moving object, and obtaining means for obtaining a distance to the moving object detected by said detection means, said acquisition means When the distance acquired in It is characterized by having a control means for controlling the intensity of the visible light .

According to the present invention, it is possible to suppress the influence on the eyes while ensuring the monitoring function.

It is a block diagram of the imaging system including the imaging apparatus. It is a block diagram of an image pickup apparatus. It is a block diagram of a determination part. It is a figure (FIG. (a)) which shows the state of irradiating only infrared light, and the figure (FIG. (b)) which shows the state of irradiating and imaging by irradiating infrared light and visible light. It is a flowchart of lighting control in an infrared light mode. It is a flowchart of lighting control in an infrared light mode.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)
FIG. 1 is a configuration diagram of an imaging system including an imaging device according to the first embodiment of the present invention. This imaging system has an imaging device 1000, and the imaging device 1000 and the client device 2000, which is an external device, are connected to each other so as to be able to communicate with each other via a network 1500. The client device 2000 transmits various control commands to the image pickup device 1000. These control commands include, for example, commands for starting and stopping imaging, illuminating the lighting device, and the like. Further, the imaging device 1000 that has received each control command transmits a response to the received control command to the client device 2000.

The image pickup device 1000 is an example of an image pickup device that has a predetermined angle of view and captures a subject 3000, and is, for example, a surveillance camera that captures a moving image. More specifically, it is assumed that the image pickup apparatus 1000 is a network camera used for surveillance. The client device 2000 is an example of an external device such as a PC (personal computer). The network 1500 shall be composed of a plurality of routers, switches, cables, etc. that satisfy communication standards such as Ethernet (registered trademark). However, the communication standard, scale, and configuration are not limited as long as they can communicate between the image pickup apparatus 1000 and the client apparatus 2000. For example, the network 1500 may be configured by the Internet, a wired LAN (Local Area Network), a wireless LAN (Wireless LAN), a WAN (Wide Area Network), or the like. The imaging device 1000 may be compatible with PoE (Power Over Ethernet (registered trademark)), for example, and power may be supplied via a LAN cable.

FIG. 2 is a block diagram of the image pickup apparatus 1000. The image of the subject 3000 (subject image) passes through the image pickup optical system 200 and the infrared filter 201, and is incident on the image pickup element 202 (imaging means) such as a CCD or CMOS sensor. Although the imaging optical system 200 is represented as one lens in FIG. 2, it may be composed of a plurality of lenses. Further, the infrared filter 201 has a plurality of filters such as an optical low-pass filter and an optical band-pass filter, and one or a plurality of them may be arbitrarily selected. Further, as the infrared filter 201, a dimming filter that dims the amount of incident light or a polarizing filter that shields light in a predetermined polarization direction may be used. The optical system control unit 206 performs mechanical driving related to focusing control, zoom control, exposure control, vibration isolation control, etc. of the imaging optical system 200 according to the instruction of the system controller 205. Further, the system controller 205 determines the imaging conditions for imaging with a predetermined exposure such as the aperture value, the shutter speed, and the gain based on the predetermined program diagram.

The subject image formed on the image sensor 202 is converted into an image signal and input to the image processing unit 203. The image processing unit 203 performs predetermined image processing such as gamma correction and color balance adjustment on the input image to generate an image file such as JPEG. The system controller 205 performs a predetermined display process on the output image processed by the image processing unit 203, and displays the image on the display unit 204. The determination unit 207 is controlled by the system controller 205, analyzes the input image, and determines the lighting equipment control method based on the result. The device control unit 208 controls the lighting of the infrared illumination unit 210 (first irradiation means) and the visible illumination unit 212 (second irradiation means) provided in the image pickup apparatus 1000 according to the instruction of the system controller 205. Specifically, the device control unit 208 uses the first switching unit 209 to control the infrared illumination unit 210, and the second switching unit 211 to control the lighting of the visible illumination unit 212. The device control unit 208 plays a role as a control means in cooperation with the system controller 205. The filter control unit 213 uses the drive unit 214 to control the insertion / removal of the infrared filter 201 provided in the image pickup apparatus 1000 according to the instruction of the system controller 205.

The system controller 205 includes a CPU 216 and a memory 217, controls each component of the image pickup apparatus 1000 in an integrated manner, and sets various parameters and the like. The memory 217 is a memory capable of electrically erasing data, and stores a program executed by the system controller 205. The memory 217 is used as a program storage area executed by the system controller 205, a work area during program execution, a data storage area, and the like. In addition, the memory 217 holds initial values of various parameters which are setting information used by the system controller 205 for controlling the image pickup apparatus 1000. Further, the memory 217 includes a time measuring unit (not shown), and can perform time counting for a predetermined period or the like at an arbitrary timing. In addition to receiving each control command from the client device 2000, the communication unit 215 transmits a response to each control command and a video stream to the client device 2000.

The above is an example of the basic configuration of the image pickup apparatus 1000. In addition, in order to make the explanation easy to understand, the filter control unit 213 and the device control unit 208 are introduced here, but these are abolished and the system controller 205 is directly used as the first switching unit 209 and the second switching unit 209. It may be connected to the switching unit 211.

FIG. 3 is a block diagram of the determination unit 207. The determination unit 207 includes a moving object detection unit 301, a time calculation unit 302, a distance calculation unit 303, an irradiated light amount calculation unit 304, and a stored light amount calculation unit 305. The moving object detection unit 301 detects a moving object, that is, determines the presence or absence of the moving object from the entire screen or a part of the image input from the image processing unit 203. When the moving object is detected by the moving object detecting unit 301, the time calculation unit 302 measures the staying time, which is the period during which the moving object exists within the imaging range. The distance calculation unit 303 calculates the distance from the image pickup device 1000 to the moving object. The irradiated light amount calculation unit 304 per unit time of infrared illumination that a moving object is exposed to based on the intensity of infrared light emitted by the infrared illumination unit 210 and the distance calculated by the distance calculation unit 303. The amount of light to be irradiated is calculated. The accumulated light amount calculation unit 305 is an accumulated infrared irradiation light amount that the moving object is exposed to based on the staying time measured by the time calculation unit 302 and the irradiated light amount calculated by the irradiated light amount calculation unit 304. Calculate the amount of light.

In the present embodiment, the infrared illumination unit 210 can irradiate infrared light which is invisible light. The visible illumination unit 212 can irradiate visible light having a wavelength different from the light emitted by the infrared illumination unit 210. The image pickup apparatus 1000 has a plurality of imaging modes, and can image a subject image in an infrared light mode for imaging with infrared light, and can also capture a subject image in a visible light mode for imaging with visible light. Further, in the present embodiment, visible light is emitted in parallel with infrared light in the infrared light mode. FIGS. 4 (a) and 4 (b) show a comparison between the conventional imaging mode that does not use visible light and the present embodiment.

FIG. 4A is a diagram showing a state in which an image is taken by irradiating only infrared light with a conventional imaging device. FIG. 4B is a diagram showing a state in which infrared light and visible light are irradiated and imaged in the infrared light mode of the present embodiment.

In the example of FIG. 4A, only the infrared light 401 (infrared illumination) is turned on, and the visible light 402 (visible illumination) is not turned on. Subject 3000, which is a human, cannot perceive infrared light 401. Therefore, if the pupil 3001 of the eye of the subject 3000 is in a wide open state and the subject 3000 faces the direction of the image pickup apparatus 1000, the amount of infrared light 401 incident on the inside of the eye increases. It is not preferable for health to look directly at the infrared light 401 for a long time.

In the example of FIG. 4B, the infrared light 401 and the visible light 402 are turned on. When the subject 3000 perceives the visible light 402, the pupil 3001 of the eye contracts. Therefore, even if the intensity of the infrared light 401 remains the same, the effect of reducing the amount of the infrared light 401 incident on the inside of the eye can be expected. Here, the irradiation range of the visible light 402 is equal to or larger than the irradiation range of the infrared light 401. Consider a case where a person (subject 3000) enters the angle of view as a moving object from outside the angle of view of the image pickup apparatus 1000. Since the visible light 402 is irradiated to the subject 3000 before or at the same time when the subject 3000 enters the irradiation range of the infrared light 401, the contraction of the iris of the eyes of the subject 3000 can be promoted at an early stage, and the pupil is enlarged. It is possible to reduce the possibility of being exposed to infrared light in the open state. Therefore, the amount of infrared light 401 incident on the eye can be suppressed and the influence on the human body can be reduced.

It is desirable that the infrared light 401 has a high intensity that allows long-distance monitoring, and the visible light 402 has a low intensity that reaches the vicinity of the image pickup apparatus 1000. By doing so, since the visible light 402 is hard to be noticed by a distant person, it is possible to continuously acquire and monitor a distant image while reducing the influence on a distant person. Further, the irradiation direction of the visible light 402 may be set so that the reachable distance of the visible light 402 is shorter than that of the infrared light 401.

FIG. 5 is a flowchart of illumination control in the infrared light mode. The processing of this flowchart is realized by the CPU 216 reading the program stored in the memory 217 included in the system controller 205 into the work area of the memory 217 and executing the program. This process is started when the start of infrared mode is instructed. The start of the infrared mode is instructed by the user from an operation unit (not shown) or from the client device 2000 via the communication unit 215.

First, in step S501, the system controller 205 (hereinafter, may be abbreviated as “controller 205”) controls the device control unit 208 (FIG. 2) to light the infrared illumination unit 210 and the visible illumination unit 212. Let me. The initial intensity of the infrared light emitted from the infrared illumination unit 210 and the initial intensity of the visible light emitted from the visible illumination unit 212 in step S501 are predetermined. Next, in step S502, the controller 205 acquires an captured image (video) from the image processing unit 203 via the determination unit 207.

Next, in step S503, the controller 205 controls the moving body detection unit 301 (FIG. 3) to detect the moving body in the image acquired from the image processing unit 203, and determines whether or not the moving body is detected. Here, a person is assumed as the moving object to be detected. Based on the detection result by the moving object detection unit 301, the controller 205 returns the process to step S501 if it is not determined that the moving object has been detected, and proceeds to the process S504 if it determines that the moving object has been detected. In step S504, the controller 205 controls the time calculation unit 302 to start measuring the staying time T in which the moving object detected in step S503 stays within the imaging range.

In step S505, the controller 205 sets the subject distance D, which is the distance between the image pickup device 1000 and the target, as the distance calculation unit for the moving object detected in step S503 (hereinafter, the target moving object is referred to as the subject 3000). Calculated according to 303. At the same time, the controller 205 determines whether or not the subject distance D is equal to or less than the threshold value. Here, the method of calculating the distance to the target is not limited, and for example, a distance measuring mechanism (not shown) may be used. The threshold value is the closest distance that can be focused. Therefore, in the focusing control of the imaging optical system 200, the determination in step S505 may be performed depending on whether the focusing position of the target is in front of or behind the nearest one. Then, when the calculated subject distance D exceeds the threshold value, the controller 205 considers that the subject 3000 is far away even within the angle of view and is not likely to be exposed to a large amount of infrared light. Return to step S501. On the other hand, when the subject distance D is equal to or less than the threshold value, the subject 3000 is nearby and may be exposed to a large amount of infrared light. Therefore, the controller 205 advances the process to step S506.

In step S506, the controller 205 controls the stored light amount calculation unit 305 to start calculating (estimating) the stored light amount of the infrared light that the subject 3000 is exposed to. In the calculation of the accumulated light amount, at least the staying time T and the irradiated light amount per unit time calculated by the irradiated light amount calculating unit 304 are used. As described above, the intensity of infrared light and the subject distance D are used to calculate the amount of irradiated light. The longer the staying time T, the higher the intensity of infrared light, and the shorter the subject distance D, the larger the amount of accumulated light.

In step S507, the controller 205 determines whether or not the calculated stored light amount exceeds a predetermined value (stored light amount> predetermined value is satisfied). Here, the predetermined value is set to a value sufficiently low so that the influence of infrared illumination on the human eye is within an allowable range. Then, when the accumulated light amount> the predetermined value is not satisfied, the influence on the eyes is small, so that the controller 205 returns the process to step S501. Therefore, if the amount of accumulated light is within a predetermined value, shooting with infrared light turned on is continued. On the other hand, when the accumulated light amount> a predetermined value is satisfied, the influence on the eyes becomes large if the infrared light irradiation is continued. Therefore, in step S508, the infrared illumination unit 210 is turned off and the infrared light irradiation is stopped. .. Here, instead of turning off the infrared light, the intensity of the infrared light may be controlled to be lower than before. After that, the process of FIG. 5 ends.

According to the present embodiment, in the shooting in the infrared mode, in parallel with the irradiation of the infrared light 401 by the infrared illumination unit 210, a wide range equal to or larger than the irradiation range of the infrared light 401 by the infrared illumination unit 210. The visible illumination unit 212 irradiates the visible light 402. As a result, the influence on the eyes can be suppressed while ensuring the monitoring function.

Further, when the subject 3000 enters the angle of view as a moving object, the controller 205 measures the staying time T, and the subject 3000 is exposed to the subject 3000 based on the staying time T, the intensity of the infrared light 401, and the subject distance D. Estimate the amount of accumulated infrared light. Then, when the stored light amount exceeds a predetermined value, the controller 205 lowers the intensity of the infrared light 401 (turns off) than before. As a result, the integrated irradiation amount of the infrared light 401 can be suppressed to protect the eyes.

When the subject 3000 detected as a moving object moves out of the imaging range or moves to a position exceeding the threshold value, the calculation of the accumulated light amount may be temporarily stopped or initialized. When the calculation of the accumulated light amount is temporarily stopped, the controller 205 may determine by image analysis or the like whether or not the moving body that has entered the imaging range after that is the same as the moving body that has entered the previous time. Then, in the case of re-invasion of the same moving object, the controller 205 may restart the calculation of the accumulated light amount from the paused timekeeping state.

(Second Embodiment)
In the second embodiment of the present invention, the processing of illumination control in the infrared light mode is different from that of the first embodiment. Therefore, the present embodiment will be described with reference to FIG. 6 instead of FIG. 5 with respect to the first embodiment.

FIG. 6 is a flowchart of illumination control in the infrared light mode. The execution conditions and start timing of the processing of this flowchart are the same as those of the flowchart of FIG. In step S601, the controller 205 controls the device control unit 208 to light the infrared illumination unit 210 and blink the visible illumination unit 212. In steps S602 to S605, the controller 205 executes the same process as in steps S502 to S505 of FIG. In step S606, the controller 205 switches the visible illumination unit 212 from blinking to lighting (constant light emission), and proceeds with the process to step S607.

In steps S607 to S609, the controller 205 executes the same process as in steps S506 to S508 of FIG. Next, in step S710, the controller 205 switches the imaging mode from the infrared light mode to the visible light mode, which is a color photographing mode, and ends the process of FIG.

According to the present embodiment, the same effect as that of the first embodiment can be obtained with respect to suppressing the influence on the eyes while ensuring the monitoring function. Further, even if a moving object is detected, the visible illumination unit 212 is in a blinking state until the subject distance D becomes equal to or less than the threshold value, so that the power consumption can be reduced. Moreover, when the subject distance D is equal to or less than the threshold value, the visible illumination unit 212 is turned on, so that the influence on the eyes of a person at a short distance can be reduced. Further, when the accumulated light amount exceeds a predetermined value, the infrared illumination is turned off and then the color shooting mode is switched to, so that the near monitoring ability can be improved at the cost of the distant monitoring ability being lowered.

In the present embodiment, the timing of switching from blinking of visible light 402 to lighting is after the subject distance D becomes equal to or less than the threshold value. However, if a moving object is detected in step S603, the visible light 402 may be switched to lighting. The intensity of the visible light 402 is switched by blinking at first and then lighting, but the present invention is not limited to this, and the emission intensity in step S606 may be higher than the emission intensity in step S601. ..

In each of the above embodiments, the intensity of visible light 402 was fixed at a fixed value when calculating the amount of stored light. However, the intensity of the visible light 402 may be variably configured and the visible light intensity may be included as a parameter when calculating the accumulated light amount. That is, the higher the visible light intensity, the smaller the pupil, so that the amount of irradiated light per unit time becomes smaller. In consideration of this, the arithmetic formula may be set so that the higher the visible light intensity, the smaller the rate of increase in the accumulated light amount with the passage of time. For example, when the visible light intensity is specified in advance by the user, it is conceivable to calculate the accumulated light amount according to the specified visible light intensity. As an example of making the visible light intensity variable, it is conceivable that the visible light intensity is gradually increased as the subject distance D becomes closer.

In each of the above embodiments, the controller 205 controlled the infrared illumination unit 210 and the visible illumination unit 212. However, the infrared illumination unit 210 and the visible illumination unit 212 may be controlled by remote operation from the client device 2000 via the network 1500. That is, each control process described as being executed by the controller 205 may be performed from an external device such as the client device 2000. The invisible light is not limited to infrared light as long as it can be used for imaging.

(Other embodiments)
The present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiment is supplied to the system or device via a network or various storage media, and the computer (or CPU, MPU, etc.) of the system or device reads the program code. This is the process to be executed. In this case, the program and the storage medium storing the program constitute the present invention.

Although the present invention has been described in detail based on the preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various embodiments within the scope of the gist of the present invention are also included in the present invention. included. Some of the above-described embodiments may be combined as appropriate.

202 Image sensor 210 Infrared illumination unit 212 Visible illumination unit 401 Infrared light 402 Visible light

Claims (10)

An imaging unit which can image an object scene member by invisible light,
The first irradiation means for irradiating the invisible light and
In parallel with the irradiation of the non-visible light by the first irradiating means, a second irradiating means for irradiating the visible light,
Detection means to detect moving objects and
An acquisition means for acquiring the distance to a moving object detected by the detection means, and
When the distance acquired by the acquisition means is equal to or less than the closest distance that can be focused by the imaging means, the second irradiation means is more than before the acquired distance is equal to or less than the closest distance. Control means for controlling to increase the intensity of the visible light irradiated by
An imaging device characterized by having. An imaging means that can image a subject in a mode that captures images with invisible light,
The first irradiation means for irradiating the invisible light and
A second irradiation means for irradiating visible light in parallel with the irradiation of the invisible light by the first irradiation means,
Detection means to detect moving objects and
A measuring means for measuring the time that a moving object detected by the detecting means stays within the imaging range of the imaging means, and a measuring means.
An acquisition means for acquiring the distance to the moving object, and
Wherein based on the distances acquired by the acquisition means and the time measured by the measuring means, to that an imaging device, comprising a control means for controlling the first irradiation means. The control means estimates the integrated irradiation amount of the invisible light based on the measured time, the acquired distance, and the intensity of the invisible light irradiated by the first irradiation means. When the estimated integrated irradiation amount exceeds a predetermined value, the claim is characterized in that the intensity of the invisible light irradiated by the first irradiation means is controlled to be lower than before. Item 2. The imaging apparatus according to Item 2 . In the mode of imaging with the invisible light, the control means turns on the invisible light by the first irradiation means, and when the integrated irradiation amount exceeds the predetermined value, the first irradiation means does not. The imaging device according to claim 3 , wherein the visible light is turned off. When the integrated irradiation amount exceeds the predetermined value, the control means increases the intensity of the visible light irradiated by the second irradiation means and does not increase the intensity of the visible light emitted by the first irradiation means. The imaging device according to claim 4 , wherein after turning off the visible light, the imaging mode of the imaging means is switched from the mode of imaging with the invisible light to the mode of photographing with the visible light. The imaging device according to any one of claims 3 to 5 , wherein the control means estimates the integrated irradiation amount after the acquired distance becomes equal to or less than a threshold value. The imaging device according to any one of claims 1 to 6 , wherein the invisible light is infrared light. An imaging unit which can image an object scene member by invisible light,
The first irradiation means for irradiating the invisible light and
Parallel with the irradiation of the non-visible light by the first irradiation means, a control method of an imaging device having a second irradiating means for irradiating the visible light, and
Detects a moving object,
Obtain the distance to the detected moving object and
When the acquired distance is equal to or less than the closest distance that can be focused by the imaging means, the second irradiation means irradiates the image more than before the acquired distance becomes less than or equal to the closest distance. A control method for an imaging device, which comprises controlling the intensity of visible light to be high . An imaging means that can image a subject in a mode that captures images with invisible light,
The first irradiation means for irradiating the invisible light and
A method for controlling an imaging device having a second irradiation means for irradiating visible light in parallel with the irradiation of the invisible light by the first irradiation means.
Detects moving objects
The time during which the detected moving object stays within the imaging range of the imaging means is measured.
Obtain the distance to the moving object and
The method of on the basis of the measured time and the distance the acquired first feature and to that imaging device to control the illumination means. A program comprising causing a computer to execute the control method of the imaging device according to claim 8 or 9 .

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