JP7781048B2 - Video transmission delay time measurement system and video transmission delay time measurement method - Google Patents

Description

This disclosure relates to a video transmission delay time measurement system and a video transmission delay time measurement method.

When captured video is displayed on a display device located remotely from the shooting location, a time delay occurs between the time the video is captured and the time it is displayed. This time delay occurs because of the time required for encoding the captured video data, transmitting the encoded video data, transmitting the video data over a network, receiving the video data on the display device, decoding the received video data, and displaying the video based on the decoded video data.

In response to this, Patent Document 1 discloses a video transmission time measurement system that includes a blinking marker placed at the imaging location, an imaging location time timer placed at the imaging location, a light-receiving sensor that detects the blinking of the blinking marker projected and displayed by a video projection device placed at the projection location, a projection location time timer that is synchronized with the imaging location time timer, and a measurement camera that is placed at the projection location and captures the image projected and displayed by the video projection device and the projection location time timer side by side. In this video transmission time measurement system, the imaging location time timer and the blinking marker are captured together by the imaging video camera, and the captured image is projected and displayed by the video projection device. Furthermore, the measurement camera simultaneously captures the projected and displayed image of the imaging location time timer and the projected location time timer, the time display of which is fixed according to the output from the light-receiving sensor, and the video transmission time is determined by reading the times of both timers from the captured image.

JP 2009-171334 A

Technology is known for remotely controlling objects such as ships, vehicles, and various types of equipment from a remote location. When performing such remote control, an operator may capture an image of the area in front of the object's direction of movement so that the object's movement in response to the remote control can be recognized. The operator may then remotely control the object while viewing the captured image. In such cases, if there is a time delay between capturing the image and displaying it, problems may arise, so it is desirable to measure the delay time in video transmission more accurately.

However, the delay time between capturing and displaying a video can vary depending on various circumstances. For example, some codec technologies for encoding video data compress and transmit the difference between a video and the immediately preceding video. When using such codec technologies, if there is little movement in the captured video, the difference between the video and the previous video will be small, whereas if there is a lot of movement in the video, the difference between the video and the immediately preceding video will be large. The larger the difference between the videos, the longer the time required for encoding, transmitting, and other processes of the video data.
Furthermore, the time required for the transmission processing of video data also varies depending on, for example, the communication conditions of various networks that transmit the video data.

For this reason, it is desirable to measure the delay time of video transmission more accurately while actually capturing video, transmitting the video data to a remote location, and displaying the video data at the remote location.
In contrast, the configuration disclosed in Patent Document 1 is not designed to measure the delay time of video transmission, which can fluctuate from moment to moment, while actually capturing video.

The present disclosure has been made to solve the above-mentioned problems, and aims to provide a video transmission delay time measurement system and a video transmission delay time measurement method that can measure the delay time from when a video is captured until it is displayed while actually capturing the video.

In order to solve the above problem, the video transmission delay time measurement system according to the present disclosure comprises a transmission unit disposed at a shooting location and a receiving unit installed at a remote location away from the shooting location, the transmission unit comprising: a transmitting GPS signal receiving unit that receives a GPS (Global Positioning System) signal at the shooting location; a transmitting reference signal transmitting unit that transmits a transmitting reference signal synchronized with the GPS signal received by the transmitting GPS signal receiving unit; a blinking marker that periodically blinks a marker light based on the transmitting reference signal; a shooting device that captures video including the subject and the blinking marker at the shooting location; and a data transmitting unit that transmits data of the video captured by the shooting device, and the receiving unit comprises: a data receiving unit that receives the video data; and a display device that displays video based on the received video data. The system includes a first blinking detection unit that detects blinking of the marker light in the image displayed on the display device, a receiving GPS signal receiving unit that receives a GPS signal at the remote location, a receiving reference signal transmitting unit that transmits a receiving reference signal synchronized with the GPS signal received by the receiving GPS signal receiving unit, and a delay time information output unit that outputs information regarding the image transmission delay time from when the image is captured by the imaging device to when it is displayed on the display device, based on the blinking signal indicating the blinking state of the marker light detected by the first blinking detection unit and the receiving reference signal.

The video transmission delay time measuring method disclosed herein includes the steps of receiving a GPS signal at a shooting location, transmitting a transmitting reference signal synchronized with the received GPS signal, periodically flashing a marker light based on the transmitting reference signal, capturing video at the shooting location including a subject and the flashing marker, transmitting data of the captured video, receiving the video data at a remote location away from the shooting location, displaying video based on the received video data, detecting flashing of the marker light in the displayed video, receiving a GPS signal at the remote location, transmitting a receiving reference signal synchronized with the GPS signal received at the remote location, and outputting information regarding the video transmission delay time from when the video is captured by the shooting device to when it is displayed on the display device based on the detected flashing signal indicating the flashing state of the marker light and the receiving reference signal.

The video transmission delay time measurement system and video transmission delay time measurement method disclosed herein make it possible to measure video transmission delay time while actually capturing video.

1 is a diagram illustrating a configuration of a video transmission delay time measuring system according to a first embodiment of the present disclosure. 3 is a diagram showing an example of a signal used in the video transmission delay time measurement system. FIG. 1 is a flowchart showing the procedure of a video transmission delay time measuring method according to a first embodiment of the present disclosure. FIG. 10 is a diagram illustrating a configuration of a video transmission delay time measuring system according to a second embodiment of the present disclosure. 3 is a diagram showing an example of a signal used in the video transmission delay time measurement system. FIG. 10 is a diagram showing an example of a signal with an adjusted period used in the video transmission delay time measurement system. FIG. FIG. 10 is a diagram illustrating a configuration of a video transmission delay time measuring system according to a third embodiment of the present disclosure. FIG. 10 is a diagram illustrating a configuration of a video transmission delay time measuring system according to a fourth embodiment of the present disclosure.

Hereinafter, embodiments for implementing a video transmission delay time measuring system and a video transmission delay time measuring method according to the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to these embodiments.
First Embodiment
(Configuration of video transmission delay time measurement system)
As shown in FIG. 1, the video transmission delay time measuring system 1A includes a transmitting unit 2 placed at a shooting location and a receiving unit 5 installed at a remote location away from the shooting location.

The transmission unit 2 is disposed at a photographing location where it is possible to photograph the subject T. The transmission unit 2 is provided, for example, at an operation subject that is remotely controlled by a remote control device (not shown).
Examples of the operation target include various moving bodies such as ships, vehicles, etc. In the case of these moving bodies, the transmission unit 2 is mounted on the moving body, and the imaging device 3 of the transmission unit 2 captures an image of the area ahead in the direction of travel of the moving body as the imaging target T.
Examples of the operation target include various devices and apparatuses. In this case, the imaging device 3 of the transmission unit 2 captures an image of, for example, a part of the device or apparatus that is to be remotely operated as the imaging target T. The transmission unit 2 may be attached to the device or apparatus, or may be provided on the floor, wall, ceiling, etc. around the device or apparatus.

The transmitting unit 2 includes a photographing device 3, a blinking marker 4, and a transmitting controller 20.
The photographing device 3 photographs an image including the subject T and the blinking marker 4 at a photographing location.

The blinking marker 4 is positioned within the range 3a that can be photographed by the photographing device 3. An example of the blinking marker 4 is an LED (Light Emitting Diode). The blinking marker 4 is fixed to the photographing device 3, for example, via a fixing member 31. As a result, if vibrations or the like occur in the photographing subject T, the blinking marker 4 and the photographing device 3 vibrate together, preventing the blinking marker 4 from displacing relative to the photographing device 3 within the photographing range 3a of the photographing device 3. The blinking marker 4 periodically blinks its marker light 4m at a predetermined blinking cycle under the control of the transmitting controller 20. The photographing device 3 photographs the blinking state of the marker light 4m of the blinking marker 4.

The transmitting controller 20 can be configured using a computer such as a microcomputer or CPU (Central Processing Unit), and hardware such as computer peripheral circuits and devices. In this embodiment, the transmitting controller 20 is configured as a control board equipped with a microcomputer. The transmitting controller 20 has a functional configuration consisting of a combination of hardware and software such as a program executed by the computer, including an imaging control unit 21, a marker control unit 22, a transmitting GPS signal receiving unit 23, a transmitting reference signal transmitting unit 24, and a data transmitting unit 25.

The photographing control unit 21 controls the operation of the photographing device 3. Specifically, the photographing control unit 21 outputs a command to the photographing device 3 to perform photographing. The photographing control unit 21 executes encoding processing of the data of the video photographed by the photographing device 3. Note that the encoding processing of the video data may be performed using a function provided in the photographing device 3.
The marker control unit 22 controls the blinking operation of the blinking marker 4 .

The transmitting GPS signal receiving unit 23 receives, for example, a GPS signal at the shooting location. The GPS signal includes highly accurate time information.
2, the transmitter reference signal transmitter 24 transmits a transmitter reference signal Sg1 synchronized with the GPS signal received by the transmitter GPS signal receiver 23. An example of the transmitter reference signal Sg1 synchronized with the GPS signal is a 1 PPS (Pulse Per Second) signal, which is a pulse signal whose signal state switches at predetermined time intervals. The transmitter reference signal Sg1 (1 PPS signal) is a pulse signal that periodically repeats ON and OFF within one second.

The marker control unit 22 causes the marker light 4m of the blinking marker 4 to blink periodically, for example, every second, based on the transmitting reference signal Sg1 (1 PPS signal) transmitted by the transmitting reference signal transmission unit 24. The blinking marker 4 periodically alternates between an on state and an off state every second.

The data transmission unit 25 transmits data of the video captured by the camera device 3. The data transmission unit 25 executes processing to transmit the video data encoded by the camera control unit 21. Note that the data transmission unit 25, which is responsible for the transmission processing of the data of the video captured by the camera device 3, may use a function provided by the camera device 3.

The receiving unit 5 is installed at a remote location away from the shooting location. The remote location is at least a distance from the shooting location that makes it impossible or difficult to directly see the shooting location. There is no limitation on the distance from the shooting location to the remote location. In an embodiment of the present disclosure, the receiving unit 5 is installed at a location (remote location) where data communication is possible between the receiving unit 5 and the transmitting unit 2 via various networks 100.
The receiving unit 5 includes a receiving controller 50 , a display device 6 , and a first blinking detection unit 7 .

The receiving controller 50 can be configured using a computer such as a microcomputer or CPU (Central Processing Unit), and hardware such as computer peripheral circuits and devices. In this embodiment, the receiving controller 50 is configured using a control board equipped with a microcomputer. The receiving controller 50 has a functional configuration consisting of a combination of hardware and software such as a program executed by the computer, including a data receiving unit 51, a display control unit 52, a receiving GPS signal receiving unit 53, a receiving reference signal transmitting unit 54, and a delay time information output unit 55.

The data receiving unit 51 receives the video data transmitted from the data transmitting unit 25 via the network 100 .
The display control unit 52 controls the display of video on the display device 6. The display control unit 52 performs processing such as decoding the video data received by the data receiving unit 51 and displaying the video based on the decoded video data. Note that the data receiving unit 51, which is responsible for receiving the video data transmitted from the data transmitting unit 25, and the display control unit 52, which is responsible for decoding the received video data and displaying the video, may use functions provided in the display device 6.

The receiving-side GPS signal receiving unit 53 receives the GPS signal at the remote location.
The receiving-side reference signal transmitter 54 transmits a receiving-side reference signal Sg2 (1 PPS signal) synchronized with the GPS signal received by the receiving-side GPS signal receiver 53 .

The display device 6 displays an image based on the data received by the data receiving unit 51 under the control of the display control unit 52. The image displayed on the display device 6 includes an image of the subject T and the blinking marker 4 captured by the imaging device 3. In other words, part of the image displayed on the display device 6 shows the blinking marker light 4m of the blinking marker 4.

The first blinking detection unit 7 detects the blinking of the marker light 4m in the image displayed on the display device 6. An example of the first blinking detection unit 7 is a photodiode. The position of the blinking marker 4 relative to the image capture device 3 is fixed. Therefore, the position of the marker light 4m of the blinking marker 4 is constant in the image displayed on the display device 6. The first blinking detection unit 7 is fixed to match the position of the marker light 4m of the blinking marker 4 in the image displayed on the display device 6.

The first blinking detection unit 7 detects the blinking state (on or off) of the marker light 4m. The first blinking detection unit 7 outputs a blinking signal Sgm indicating the blinking state of the marker light 4m to the delay time information output unit 55.

The blinking signal Sgm is a waveform signal that indicates the switching of the signal state in response to the lighting and extinguishing of the blinking marker 4. This blinking signal Sgm includes a delay time relative to the timing at which the blinking marker 4 of the transmitting unit 2 blinks the marker light based on the transmitting side reference signal Sg1 (1 PPS signal). The delay time of the blinking signal Sgm relative to the timing at which the blinking marker 4 blinks the marker light matches the video transmission delay time until the video captured by the imaging device 3 is displayed on the display device 6.

The delay time information output unit 55 outputs information about the video transmission delay time Td from when the video is captured by the imaging device 3 to when it is displayed on the display device 6, based on the blinking signal Sgm indicating the blinking state of the marker light 4m detected by the first blink detection unit 7 and the receiving-side reference signal Sg2. An example of the delay time information output unit 55 is an oscilloscope that outputs (displays) the receiving-side reference signal Sg2 and the blinking signal Sgm as visible waveform information, etc. In this case, the delay time information output unit 55 displays the waveform of the receiving-side reference signal Sg2 and the waveform of the blinking signal Sgm in parallel as information about the video transmission delay time Td. The delay time information output unit 55 outputs information about the video transmission delay time Td based on the timing at which the signal state of the receiving-side reference signal Sg2 changes and the timing at which the signal state of the blinking signal Sgm changes.
The person in charge of the receiving unit 5 can ascertain the video transmission delay time Td from the time difference between the receiving side reference signal Sg2 and the blinking signal Sgm, which is displayed on the delay time information output section 55.

Here, the video transmission delay time Td can be, for example, the time difference between when the receiving side reference signal Sg2 turns ON and when the blinking signal Sgm switches from an off state to an on state. The video transmission delay time Td is not limited to this, and can also be, for example, the time difference between when the receiving side reference signal Sg2 turns OFF and when the blinking signal Sgm switches from an on state to an off state.

The delay time information output unit 55 may use a function of the oscilloscope to calculate the video transmission delay time Td based on the timing at which the signal state of the receiving-side reference signal Sg2 changes and the timing at which the signal state of the blinking signal Sgm changes. The oscilloscope as the delay time information output unit 55 outputs (displays) the calculated value of the video transmission delay time Td.
In addition, the delay time information output unit 55 may calculate the difference between the timing at which the signal state of the receiving side reference signal Sg2 changes and the timing at which the signal state of the flashing signal Sgm changes as the video transmission delay time Td based on the waveform of the receiving side reference signal Sg2 and the waveform of the flashing signal Sgm.

(Video transmission delay time measurement procedure)
As shown in FIG. 3 , the video transmission delay time measuring method according to an embodiment of the present disclosure includes step S11 of receiving a GPS signal at a shooting location, step S12 of transmitting a transmitting-side reference signal Sg1, step S13 of blinking a marker light, step S14 of shooting a video, step S15 of transmitting video data, step S21 of receiving the video data, step S22 of displaying the video, step S23 of detecting the blinking of the marker light, step S24 of receiving a GPS signal at a remote location, step S25 of transmitting a receiving-side reference signal Sg2, and step S26 of outputting information related to the video transmission delay time Td.

In step S11 of receiving GPS signals at the shooting location, the transmitting GPS signal receiving unit 23 of the transmitting unit 2 receives GPS signals at the shooting location.

In step S12 of transmitting the transmitting reference signal Sg1, the transmitting reference signal Sg1 (see Figure 2) synchronized with the GPS signal Sg0 received by the transmitting GPS signal receiving unit 23 is transmitted.

In step S13 of flashing the marker light, the marker control unit 22 causes the flashing marker 4 to flash periodically, for example, every second, based on the transmitting side reference signal Sg1 (1 PPS signal) transmitted by the transmitting side reference signal transmission unit 24.

In step S14 of capturing video, the camera device 3 captures video at the shooting location, including the subject T and the blinking marker light 4m of the blinking marker 4, under the control of the shooting control unit 21.

In step S15 of transmitting the video data, the imaging control unit 21 performs encoding processing on the video data captured by the imaging device 3. Furthermore, the data transmission unit 25 performs processing to transmit the video data encoded by the imaging control unit 21. As a result, the video data captured by the imaging device 3 is transmitted to the receiving unit 5 via the network 100.

In step S21 of receiving video data, the data receiving unit 51 receives the video data transmitted from the data transmitting unit 25 via the network 100.

In step S22 of displaying the image, the display control unit 52 performs processes such as decoding the image data received by the data receiving unit 51 and displaying the image based on the decoded image data. As a result, the display device 6 displays the image based on the data received by the data receiving unit 51 under the control of the display control unit 52. The image displayed on the display device 6 includes the image of the subject T and the marker light 4m of the flashing marker 4 captured by the image capturing device 3.

In step S23 of detecting the blinking of the marker light, the first blinking detection unit 7 detects the blinking of the marker light 4m in the image displayed on the display device 6. The first blinking detection unit 7 detects the blinking state (on or off) of the marker light 4m. The first blinking detection unit 7 outputs a blinking signal Sgm indicating the blinking state of the marker light 4m to the delay time information output unit 55.

In step S24 of receiving GPS signals at a remote location, the receiving GPS signal receiving unit 53 receives GPS signals at the remote location where the receiving unit 5 is located.

In step S25 of transmitting the receiving-side reference signal Sg2, the receiving-side reference signal transmitter 54 transmits the receiving-side reference signal Sg2 (see Figure 2) synchronized with the GPS signal received by the receiving-side GPS signal receiver 53. The receiving-side reference signal transmitter 54 outputs the transmitted receiving-side reference signal Sg2 to the delay time information output unit 55.

In step S26, which outputs information related to the video transmission delay time Td, the delay time information output unit 55 outputs information related to the video transmission delay time Td based on the blinking signal Sgm and the receiving side reference signal Sg2. If the delay time information output unit 55 is an oscilloscope, the video transmission delay time Td can be determined based on waveform information of the receiving side reference signal Sg2 and the blinking signal Sgm held side by side on the oscilloscope. The delay time information output unit 55 may also calculate the video transmission delay time Td based on the timing at which the signal state of the receiving side reference signal Sg2 changes and the timing at which the signal state of the blinking signal Sgm changes.

(Action and effect)
According to the video transmission delay time measurement system 1A configured as described above, the camera device 3 of the transmission unit 2 arranged at the shooting location captures video of the subject, and the video data is transmitted to the receiving unit 5 by the data transmission section 25. The receiving unit 5 displays the video based on the received video data on the display device 6.
The transmitting unit 2 transmits a transmitting-side reference signal Sg1 synchronized with the GPS signal received by the transmitting-side GPS signal receiving section 23. Meanwhile, the receiving unit 5 transmits a receiving-side reference signal Sg2 synchronized with the GPS signal received by the receiving-side GPS vibration receiving section. As a result, the transmitting-side reference signal Sg1 and the receiving-side reference signal Sg2 synchronized in time are transmitted between the shooting location and a remote location separated from the shooting location.
In the transmitting unit 2, the marker light 4m of the blinking marker 4 blinks periodically based on the transmitting-side reference signal Sg1. The photographing device 3 photographs an image including the blinking marker 4 along with the subject. The display device 6 of the receiving unit 5 displays an image of the subject and the blinking marker light 4m of the blinking marker 4. The first blinking detection unit 7 detects the blinking of the marker light 4m in the image displayed on the display device 6. Therefore, the delay time information output unit 55 outputs information regarding the image transmission delay time Td from when the image is photographed by the photographing device 3 to when the image is displayed on the display device 6, based on the blinking signal Sgm indicating the blinking state of the marker light 4m detected by the first blinking detection unit 7 and the receiving-side reference signal Sg2.
Here, the receiving-side reference signal Sg2 is synchronized with the transmitting-side reference signal Sg1, and the blinking of the marker light 4m is performed based on the transmitting-side reference signal Sg1. In other words, the time difference between the blinking signal Sgm indicating the blinking state of the marker light 4m detected by the first blinking detection unit 7 and the receiving-side reference signal Sg2 is the time difference between the blinking of the marker light 4m at the shooting location and the blinking of the marker in the image displayed at a distant location, i.e., the video transmission delay time Td.
Here, the delay time information output unit 55 may output (display) as information regarding the video transmission delay time Td the time difference between the flashing signal Sgm indicating the flashing state of the marker light 4m detected by the first flashing detection unit 7 and the receiving side reference signal Sg2 using visible waveform information or the like.
In addition, the delay time information output unit 55 may calculate the time difference between the blinking signal Sgm indicating the blinking state of the marker light 4m detected by the first blinking detection unit 7 and the receiving side reference signal Sg2 as information regarding the video transmission delay time Td, and output the calculated value as the video transmission delay time Td.
In this way, the video transmission delay time Td can be obtained based on the blinking of the marker light 4m of the blinking marker 4 displayed together with the subject in the video captured by the imaging device 3. Therefore, the video transmission delay time can be measured while actually capturing the video.

Furthermore, since the transmitting side reference signal Sg1 and the receiving side reference signal Sg2 are pulse signals and the blinking signal Sgm is a waveform signal that indicates the switching of the signal state in response to the lighting and extinguishing of the blinking marker 4, the video transmission delay time Td can be easily determined by comparing the receiving side reference signal Sg2 and the blinking signal Sgm.

Furthermore, if the delay time information output unit 55 is an oscilloscope, the video transmission delay time Td can be easily grasped visually by displaying the receiving side reference signal Sg2 and the blinking signal Sgm side by side.

In addition, the delay time information output unit 55 can easily determine the video transmission delay time Td based on the timing at which the signal state of the receiving side reference signal Sg2 changes and the timing at which the signal state of the blinking signal Sgm changes.

Furthermore, the delay time information output unit 55 calculates the video transmission delay time Td based on the timing at which the signal state of the receiving side reference signal Sg2 changes and the timing at which the signal state of the blinking signal Sgm changes, making it possible to easily and accurately determine the video transmission delay time Td.

Furthermore, by fixing the flashing marker 4 and the photographing device 3 with the fixing member 31, the flashing marker 4 is prevented from moving relative to the photographing device 3 due to vibrations or the like in the image captured by the photographing device 3. Therefore, the position of the flashing marker 4 is prevented from shifting in the image displayed on the display device 6, allowing the first flashing detection unit 7 to effectively detect the flashing of the marker light 4m.

(Modification of the first embodiment)
In the first embodiment, the measurement of the video transmission delay time by the video transmission delay time measurement method as shown in FIG. 3 may be performed continuously while the video is being captured by the image capturing device 3, or may be performed intermittently at appropriate time intervals.

Second Embodiment
Next, a second embodiment of the video transmission delay time measurement system and video transmission delay time measurement method according to the present disclosure will be described. In the second embodiment described below, components common to the first embodiment will be denoted by the same reference numerals in the drawings, and their description will be omitted. The second embodiment differs from the first embodiment in that, in addition to the components shown in the first embodiment, the second embodiment includes a configuration for adjusting the blinking period of the marker light 4m in the blinking marker 4 in accordance with the video transmission delay time.

FIG. 4 is a diagram showing the configuration of the video transmission delay time measuring system according to the second embodiment.
As shown in Figure 4, in addition to the configuration of the video transmission delay time measurement system 1A, the video transmission delay time measurement system 1B further includes a receiving side blinking marker 8, a second blinking detection unit 72, a delay time abnormality determination unit 56A, and a blinking period adjustment unit 26A.

The receiving-side blinking marker 8 is provided in the receiving unit 5. The receiving-side blinking marker 8 periodically blinks the marker light based on the receiving-side reference signal Sg2. The receiving-side blinking marker 8 repeatedly blinks multiple different types of marker light 8m alternately in a predetermined order based on the receiving-side reference signal Sg2. In an embodiment of the present disclosure, the receiving-side blinking marker 8 repeatedly blinks multiple different colored marker lights 8m (e.g., red marker light 8mR, blue marker light 8mB, green marker light 8mG) in this order.

In an embodiment of the present disclosure, the blinking marker 4 of the transmitting unit 2 repeatedly blinks multiple different types of marker light 4m alternately in a predetermined sequence based on the transmitting side reference signal Sg1. In an embodiment of the present disclosure, the blinking marker 4 repeatedly blinks multiple different colored marker lights 4m (e.g., red marker light 4mR, blue marker light 4mB, green marker light 4mG) in this sequence. In other words, the receiving side blinking marker 8 and the blinking marker 4 repeatedly blink multiple common types of marker lights 8m, 4m in the same sequence.

The second blinking detector 72 is provided in the receiving unit 5. The second blinking detector 72 is, for example, a photodiode, and detects the blinking of the marker light 8m in the receiving-side blinking marker 8. As shown in FIG. 5, the blinking signal Sgr of the marker light 8m in the receiving-side blinking marker 8 detected by the second blinking detector 72 is synchronized with the receiving-side reference signal Sg2.

The delay time abnormality determination unit 56A is provided in the receiving unit 5. The delay time abnormality determination unit 56A determines whether or not there is an abnormality in the video transmission delay time Td acquired by the delay time information output unit 55. Specifically, the delay time abnormality determination unit 56A determines whether or not the video transmission delay time Td is equal to or greater than one period of the receiving-side reference signal Sg2 (one second in the above example).
To this end, the video transmission delay time Td is acquired according to the procedure shown in Fig. 3. The delay time abnormality determination unit 56A compares the blinking signal Sgm used to acquire the video transmission delay time Td with the blinking signal Sgr of the receiving-side blinking marker 8 synchronized with the blinking signal Sgm. If the type (color) of the blinking signal Sgm used to acquire the video transmission delay time Td is the same as the type of the blinking signal Sgr of the receiving-side blinking marker 8, the video transmission delay time Td is less than one period of the receiving-side reference signal Sg2.
On the other hand, as shown in Fig. 5, if the type (color) of the blinking signal Sgm used to acquire the video transmission delay time Td is different from the type of the blinking signal Sgr of the receiving-side blinking marker 8, it can be determined that the video transmission delay time Td is equal to or longer than one period of the receiving-side reference signal Sg2. In this case, the blinking period adjustment unit 26A adjusts the blinking period of the marker light 4m of the blinking marker 4. For example, as shown in Fig. 6, the blinking period adjustment unit 26A adjusts the period of the transmitting-side reference signal Sg1 to twice the length.

Thereafter, the video transmission delay time Td is acquired again according to the procedure shown in Fig. 3. The delay time abnormality determination unit 56A determines whether the blinking signal Sgm used when acquiring the video transmission delay time Td and the blinking signal Sgr of the receiving side blinking marker 8 synchronized with the blinking signal Sgm are of the same type.
Using this procedure, the blinking period adjustment unit 26A adjusts the period of the transmitting side reference signal Sg1 to twice the length until the blinking signal Sgm used to acquire the video transmission delay time Td and the blinking signal Sgr of the receiving side blinking marker 8 synchronized with the blinking signal Sgm are of the same type.

In addition to the same effects as those of the first embodiment, the video transmission delay time measurement system 1B described above can also, for example, use the blinking cycle adjustment unit 26A to make the blinking cycle of the marker light longer than the video transmission delay time Td when the video transmission delay time Td is longer than the blinking cycle of the marker light in the blinking marker 4. This makes it easier to determine the video transmission delay time Td.

Furthermore, according to the above embodiment, the periodic blinking of the marker light of the receiving-side blinking marker 8 based on the receiving-side reference signal Sg2 is detected by the second blinking detection unit 72. The blinking cycle adjustment unit 26A adjusts the blinking cycle of the marker light of the blinking marker 4 based on the marker light of the blinking marker 4 detected by the first blinking detection unit 7 and the marker light of the receiving-side blinking marker 8 detected by the second blinking detection unit 72. For example, if the type of marker light of the blinking marker 4 detected by the first blinking detection unit 7 differs from the type of marker light of the receiving-side blinking marker 8 detected by the second blinking detection unit 72, it can be determined that the video transmission delay time Td is longer than the blinking cycle of the marker light of the blinking marker 4. In this case, the blinking cycle adjustment unit 26A can adjust the blinking cycle of the marker light of the blinking marker 4 to accurately determine the video transmission delay time Td.

In the second embodiment described above, the marker light 4m of the blinking marker 4 and the marker light 8m of the receiving side blinking marker 8 were made to blink multiple types of marker light 4m, 8m by differentiating their colors. However, the marker light 4m of the blinking marker 4 and the marker light 8m of the receiving side blinking marker 8 may be made to blink multiple types of marker light by, for example, differentiating their blinking patterns.

In addition, in the second embodiment described above, the blinking cycle adjustment unit 26A adjusts the blinking cycle of the marker light of the blinking marker 4 based on the type of marker light of the blinking marker 4 detected by the first blinking detection unit 7 and the type of marker light of the receiving blinking marker 8 detected by the second blinking detection unit 72, but this is not limited to this. For example, a person in charge may visually check the type (color) of the marker light of the blinking marker 4 displayed on the display device 6 and the type (color) of the marker light of the receiving blinking marker 8 and make a judgment.

In addition, in the second embodiment described above, if the type (color) of the blinking signal Sgm used to acquire the video transmission delay time Td differs from the type of blinking signal Sgr of the receiving side blinking marker 8, the video transmission delay time Td is determined to be equal to or greater than one period of the receiving side reference signal Sg2. However, this is not limited to this. For example, a person in charge may visually check the blinking signal Sgm and the blinking signal Sgr and make a determination based on the difference in color.

Third Embodiment
Next, a third embodiment of the video transmission delay time measuring system and video transmission delay time measuring method according to the present disclosure will be described. In the third embodiment described below, components common to the first embodiment will be denoted by the same reference numerals in the drawings, and their description will be omitted. In the third embodiment, the blinking period of the marker light 4m in the blinking marker 4 is adjusted using a different configuration from that shown in the second embodiment.

FIG. 7 is a diagram showing the configuration of the video transmission delay time measuring system according to the third embodiment.
As shown in Figure 7, in addition to the configuration of the above-mentioned video transmission delay time measurement system 1A, the video transmission delay time measurement system 1C further includes a transmitting side time information display device 200, a time difference acquisition unit 300, and a blinking period adjustment unit 26B.

The transmitting side time information display device 200 is provided in the transmitting unit 2. The transmitting side time information display device 200 displays shooting location time information Tp at the shooting location. The transmitting side time information display device 200 is, for example, a smartphone, tablet terminal, personal computer, etc., and is capable of acquiring time information distributed from an external time information output unit, for example, time information distributed from an NTP (Network Time Protocol) server, as a synchronization signal with a larger synchronization error than a GPS signal. The transmitting side time information display device 200 displays the acquired time information on a monitor screen or the like provided in the transmitting side time information display device 200 as shooting location time information Tp at the shooting location. The transmitting side time information display device 200 is positioned within the field of view of the shooting device 3.
The photographing device 3 then photographs an image including the subject T, the marker light 4m of the blinking marker 4, and the photographing location time information Tp displayed on the transmitting side time information display device 200. As a result, the display device 6 displays the photographing location time information Tp in addition to the images of the subject T and the marker light 4m.

The time difference acquisition unit 300 is provided in the receiving unit 5. The time difference acquisition unit 300 is, for example, a smartphone, tablet terminal, or personal computer, and is capable of acquiring time information distributed from an external time information output unit, such as time information distributed from an NTP server. This allows the time difference acquisition unit 300 to acquire, at the remote location, remote location time information that is substantially synchronized with the shooting location time information Tp.

The time difference acquisition unit 300 also includes a camera 301 capable of capturing the shooting location time information Tp displayed on the display device 6. The time difference acquisition unit 300 reads the time displayed as the shooting location time information Tp captured by the camera 301 using appropriate character recognition processing. The time difference acquisition unit 300 acquires the difference between the read shooting location time information Tp and the separated location time information acquired at the separated location.

The difference between the shooting location time information Tp and the separated location time information acquired at the separated location includes the video transmission delay time until the shooting location time information Tp captured by the shooting device 3 is displayed on the display device 6. The time difference acquisition unit 300 determines whether the difference acquired in this manner is equal to or greater than one cycle of the receiving side reference signal Sg2 (one second in the above example). If the acquired difference is equal to or greater than one cycle of the receiving side reference signal Sg2, the time difference acquisition unit 300 notifies the blinking cycle adjustment unit 26B of the transmission unit 2 of the difference between the shooting location time information Tp and the separated location time information acquired at the separated location via the network 100, etc., using the communication function of the time difference acquisition unit 300.

Based on notification from the time difference acquisition unit 300, the blinking cycle adjustment unit 26B adjusts the blinking cycle of the marker light 4m of the blinking marker 4 according to the difference between the shooting location time information Tp and the separated location time information acquired at the separated location.

In addition to the same effects as the first and second embodiments, the video transmission delay time measurement system 1C described above has the following advantages: when the photographing device 3 photographs video including the photographing location time information Tp displayed on the transmitting side time information display device 200, the time difference acquisition unit 300 acquires the difference between the photographing location time information Tp displayed on the transmitting side time information display device 200 and the distant location time information acquired at the distant location. If the difference between the acquired photographing location time information Tp and the distant location time information is large, the blinking cycle adjustment unit 26B adjusts the blinking cycle of the marker light, allowing the video transmission delay time Td to be accurately determined.

<Fourth embodiment>
Next, a fourth embodiment of the video transmission delay time measurement system and video transmission delay time measurement method according to the present disclosure will be described. In the fourth embodiment described below, components common to the first and fourth embodiments will be denoted by the same reference numerals in the drawings, and their description will be omitted. The fourth embodiment differs from the first to third embodiments in that it includes a fault diagnosis function for the video transmission delay time measurement system.

Figure 8 shows that the video transmission delay time measurement system 1D according to the fourth embodiment of the video transmission delay time measurement system and video transmission delay time measurement method can be configured in combination with the video transmission delay time measurement systems 1A to 1C shown in the first to third embodiments. In the configuration shown in Figure 8, the video transmission delay time measurement system 1D includes a fault diagnosis unit 58 in addition to the configuration of the video transmission delay time measurement system 1A shown in the first embodiment above.

In the video transmission delay time measurement system 1D, multiple blinking markers 4 are provided. The camera device 3 is capable of changing its shooting direction using a drive device (not shown). The camera device 3 and the blinking markers 4 are capable of relative movement so as to return to their fixed positions in accordance with the blinking cycle of the blinking markers 4. The multiple blinking markers 4 blink synchronously based on the transmitting side reference signal Sg1 (see Figure 2). The camera device 3 changes its shooting direction so as to sequentially capture the multiple blinking markers 4 at the timing when the multiple blinking markers 4 are lit. As a result, the camera device 3 sequentially captures different blinking markers 4 for each blinking cycle of the multiple blinking markers 4.

As described in the first embodiment above, the receiving controller 50 can obtain the video transmission delay time Td using the blinking signal Sgm, which indicates the blinking state of the blinking marker 4 and is included in the video captured by the imaging device 3.

The fault diagnosis unit 58 is provided in the receiving controller 50. The fault diagnosis unit 58 diagnoses whether or not a fault has occurred in the transmission unit 2 based on the video captured by the imaging device 3. The fault diagnosis unit 58 compares the video captured sequentially at the blinking timing of the multiple blinking markers 4. If there is no change in the captured background video in the video captured sequentially at the blinking timing of the multiple blinking markers 4, the fault diagnosis unit 58 can diagnose that the transmission unit 2 has malfunctioned for some reason and has stopped operating. If the fault diagnosis unit 58 diagnoses that a fault has occurred, it can invalidate the video transmission delay time Td acquired at that time. Furthermore, if the fault diagnosis unit 58 diagnoses that a fault has occurred, it may notify the outside of the occurrence of the fault.

In addition to the same effects as the first to third embodiments, the video transmission delay time measurement system 1D described above moves the camera 3 and the blinking marker 4 relative to each other so that they return to their home positions in sync with the blinking cycle of the blinking marker 4. This means that if at least one of the camera 3 and the blinking marker 4 is not operating normally, the camera 3 will not be able to properly capture the blinking of the blinking marker 4. This makes it easy to determine whether the camera 3 and the blinking marker 4 are operating normally.

In the fourth embodiment, multiple blinking markers 4 are provided and the shooting direction of the camera device 3 is changed, but this is not limited to this. The blinking markers 4 may be moved relative to the camera device 3 without changing the shooting direction of the camera device 3.

Furthermore, although the fault diagnosis unit 58 performs fault diagnosis based on the image captured by the image capturing device 3, the present invention is not limited to this.
For example, if a malfunction occurs in the photographing device 3 or the flashing marker 4 on the transmitting unit 2 side, the flashing period of the marker light 4m in the image captured by the photographing device 3 will become longer than usual (including cases where it stops flashing).
Therefore, it is determined whether the video transmission delay time Td acquired by the delay time information output unit 55 exceeds a preset threshold value, and if the video transmission delay time Td is equal to or greater than the threshold value, it can be determined that a fault has occurred on the transmitting unit 2 side.

In addition, in the blinking signal Sgm, the lighting duration or extinguishing duration of the marker light 4m is set as follows:
It is determined whether or not a preset threshold is exceeded, and if the duration of lighting or lighting out is equal to or greater than the threshold, it can be determined that a failure has occurred on the transmitting unit 2 side.

The diagnosis by the fault diagnosis unit 58 shown in the fourth embodiment above may be performed at the discretion of the person in charge of the receiving unit 5.

In addition, in each of the above embodiments, the photography control unit 21 controls the operation of the photography device 3, but this is not limited to this. For example, an existing camera or the like may be used as the photography device 3, and the photography device 3 may be operated by a person in charge, with the photography operation being controlled by the photography device 3 itself.
Furthermore, the encoding process of the data of the video captured by the imaging device 3 may be performed by a separate encoder or the like, rather than by the imaging control unit 21 .

<Additional Notes>
The video transmission delay time measuring systems 1A to 1D and the video transmission delay time measuring methods described in the respective embodiments can be understood, for example, as follows.

(1) The video transmission delay time measurement systems 1A to 1D according to the first aspect include a transmission unit 2 disposed at a shooting location and a receiving unit 5 installed at a remote location away from the shooting location. The transmission unit 2 includes a transmission-side GPS signal receiving unit 23 that receives a GPS signal at the shooting location, a transmission-side reference signal transmitting unit 24 that transmits a transmission-side reference signal Sg1 synchronized with the GPS signal received by the transmission-side GPS signal receiving unit 23, a blinking marker 4 that periodically blinks a marker light based on the transmission-side reference signal Sg1, a shooting device 3 that captures video including a subject and the blinking marker 4 at the shooting location, and a data transmitting unit 25 that transmits data of the video captured by the shooting device 3. The receiving unit 5 transmits the video. a display device 6 that displays an image based on the received image data; a first blinking detection unit 7 that detects blinking of the marker light in the image displayed on the display device 6; a receiving GPS signal receiving unit 53 that receives a GPS signal at the separated location; a receiving reference signal transmitting unit 54 that transmits a receiving reference signal Sg2 synchronized with the GPS signal received by the receiving GPS signal receiving unit 53; and a delay time information output unit 55 that outputs information regarding the image transmission delay time Td from when the image is captured by the imaging device 3 to when it is displayed on the display device 6, based on the blinking signal Sgm that indicates the blinking state of the marker light detected by the first blinking detection unit 7 and the receiving reference signal Sg2.

In these video transmission delay time measurement systems 1A to 1D, a video of a subject is captured by a camera 3 of a transmission unit 2 arranged at a shooting location, and the video data is transmitted to a receiving unit 5 by a data transmission unit 25. The receiving unit 5 displays an image based on the received video data on a display device 6.
The transmitting unit 2 transmits a transmitting-side reference signal Sg1 synchronized with the GPS signal received by the transmitting-side GPS signal receiving section 23. Meanwhile, the receiving unit 5 transmits a receiving-side reference signal Sg2 synchronized with the GPS signal received by the receiving-side GPS vibration receiving section. As a result, the transmitting-side reference signal Sg1 and the receiving-side reference signal Sg2 synchronized in time are transmitted between the shooting location and a remote location separated from the shooting location.
In the transmitting unit 2, the marker light of the blinking marker 4 blinks periodically based on the transmitting-side reference signal Sg1. The photographing device 3 photographs an image including the blinking marker 4 along with the subject to be photographed. The display device 6 of the receiving unit 5 displays an image of the subject and the blinking marker light of the blinking marker 4. The first blinking detection unit 7 detects the blinking of the marker light in the image displayed on the display device 6. Therefore, the delay time information output unit 55 outputs information regarding the image transmission delay time Td from when the image is photographed by the photographing device 3 to when the image is displayed on the display device 6, based on the blinking signal Sgm indicating the blinking state of the marker light detected by the first blinking detection unit 7 and the receiving-side reference signal Sg2.
Here, the receiving-side reference signal Sg2 is synchronized with the transmitting-side reference signal Sg1, and the blinking of the marker light is performed based on the transmitting-side reference signal Sg1. In other words, the time difference between the blinking signal Sgm indicating the blinking state of the marker light detected by the first blink detection unit 7 and the receiving-side reference signal Sg2 is the time difference between the blinking of the marker light at the shooting location and the blinking of the marker in the video displayed at a distant location, i.e., the video transmission delay time Td.
Here, the delay time information output unit 55 may output (display) information regarding the video transmission delay time Td, such as the time difference between the flashing signal Sgm indicating the flashing state of the marker light detected by the first flashing detection unit 7 and the receiving side reference signal Sg2, using visible waveform information, etc.
In addition, the delay time information output unit 55 may calculate the time difference between the blinking signal Sgm indicating the blinking state of the marker light detected by the first blinking detection unit 7 and the receiving side reference signal Sg2 as information regarding the video transmission delay time Td, and output the calculated numerical value as the video transmission delay time Td.
In this way, the video transmission delay time Td can be obtained based on the blinking of the marker light of the blinking marker 4 displayed together with the subject in the video captured by the imaging device 3. Therefore, the video transmission delay time can be measured while actually capturing the video.

(2) The video transmission delay time measurement systems 1A to 1D according to the second aspect are the video transmission delay time measurement systems 1A to 1D of (1), in which the transmitting side reference signal Sg1 and the receiving side reference signal Sg2 are pulse signals whose signal state changes at predetermined time intervals, and the blinking signal Sgm is a waveform signal that indicates the switching of the signal state in response to the lighting and extinguishing of the blinking marker 4.

As a result, since the transmitting side reference signal Sg1 and the receiving side reference signal Sg2 are pulse signals and the blinking signal Sgm is a waveform signal that indicates the switching of the signal state in response to the lighting and extinguishing of the blinking marker 4, the video transmission delay time Td can be easily determined by comparing the receiving side reference signal Sg2 and the blinking signal Sgm.

(3) The video transmission delay time measurement systems 1A to 1D according to the third aspect are the video transmission delay time measurement systems 1A to 1D of (2), in which the delay time information output unit 55 is an oscilloscope that displays the receiving side reference signal Sg2 and the blinking signal Sgm side by side.

This allows the receiving side reference signal Sg2 and the blinking signal Sgm to be displayed side by side on an oscilloscope, making it easy to visually grasp the video transmission delay time Td.

(4) The video transmission delay time measurement systems 1A to 1D according to the fourth aspect are the video transmission delay time measurement systems 1A to 1D according to (2) or (3), and the delay time information output unit 55 outputs information about the video transmission delay time Td based on the timing at which the signal state of the receiving side reference signal Sg2 changes and the timing at which the signal state of the blinking signal Sgm changes.

As a result, the delay time information output unit 55 can easily determine the video transmission delay time Td based on the timing at which the signal state of the receiving side reference signal Sg2 changes and the timing at which the signal state of the blinking signal Sgm changes.

(5) The video transmission delay time measurement systems 1A to 1D according to the fifth aspect are the video transmission delay time measurement systems 1A to 1D of (4), in which the delay time information output unit 55 calculates the video transmission delay time Td based on the timing at which the signal state of the receiving side reference signal Sg2 changes and the timing at which the signal state of the blinking signal Sgm changes, and outputs the calculated value of the video transmission delay time Td.

As a result, the delay time information output unit 55 can easily and accurately determine the video transmission delay time Td by calculating the video transmission delay time Td based on the timing at which the signal state of the receiving side reference signal Sg2 changes and the timing at which the signal state of the blinking signal Sgm changes.

(6) The sixth aspect of the video transmission delay time measurement system 1A-1D is any one of the video transmission delay time measurement systems 1A-1D described in (1) to (5), and further includes a fixing member 31 that fixes the blinking marker 4 and the image capture device 3.

As a result, in the image captured by the camera device 3, for example, when the camera device 3 and flashing marker 4 are mounted on a moving object such as a ship or vehicle, or on various machines, the flashing marker 4 is prevented from moving relative to the camera device 3 due to vibrations, etc. Therefore, the position of the flashing marker 4 is prevented from shifting in the image displayed on the display device 6, allowing the first flashing detection unit 7 to effectively detect the flashing of the marker light.

(7) The video transmission delay time measurement system 1B, 1C according to the seventh aspect is any one of the video transmission delay time measurement systems 1B, 1C described in (1) to (6), in which the transmission unit 2 further includes a blinking cycle adjustment unit 26A, 26B that can adjust the blinking cycle of the marker light in the blinking marker 4.

As a result, for example, in cases where the video transmission delay time Td is longer than the blinking period of the marker light in the blinking marker 4, the blinking period of the marker light can be made longer than the video transmission delay time Td. This makes it easier to grasp the video transmission delay time Td.

(8) The video transmission delay time measuring system 1B according to the eighth aspect is the video transmission delay time measuring system 1B of (7), wherein the receiving unit 5 further includes a receiving-side blinking marker 8 that periodically blinks a marker light 8m based on the receiving-side reference signal Sg2, and a second blinking detection unit 72 that detects the blinking of the marker light 8m in the receiving-side blinking marker 8, wherein the blinking marker 4 and the receiving-side blinking marker 8 are each capable of blinking multiple types of marker lights 4m and 8m in the same order, and the blinking cycle adjustment unit 26A adjusts the blinking cycle of the marker light in the blinking marker 4 based on the type of marker light in the blinking marker 4 detected by the first blinking detection unit 7 and the type of marker light in the receiving-side blinking marker 8 detected by the second blinking detection unit 72.

As a result, the second blinking detection unit 72 detects the periodic blinking of the marker light of the receiving-side blinking marker 8 based on the receiving-side reference signal Sg2. The blinking cycle adjustment unit 26A adjusts the blinking cycle of the marker light of the blinking marker 4 based on the marker light of the blinking marker 4 detected by the first blinking detection unit 7 and the marker light of the receiving-side blinking marker 8 detected by the second blinking detection unit 72. For example, if the type of marker light of the blinking marker 4 detected by the first blinking detection unit 7 differs from the type of marker light of the receiving-side blinking marker 8 detected by the second blinking detection unit 72, it can be determined that the video transmission delay time Td is longer than the blinking cycle of the marker light of the blinking marker 4. Therefore, by adjusting the blinking cycle of the marker light of the blinking marker 4 using the blinking cycle adjustment unit 26A, the video transmission delay time Td can be accurately determined.

(9) A video transmission delay time measurement system 1C according to a ninth aspect is the video transmission delay time measurement system 1C of (7), wherein the transmitting unit 2 further includes a transmitting side time information display device 200 that displays shooting location time information Tp at the shooting location, the shooting device 3 captures the video including the shooting location time information Tp displayed on the transmitting side time information display device 200, the receiving unit 5 includes a time difference acquisition unit 300 that acquires the difference between the shooting location time information Tp displayed on the display device 6 and remote location time information synchronized with the shooting location time information Tp acquired at the remote location, and the blinking cycle adjustment unit 26B adjusts the blinking cycle of the marker light of the blinking marker 4 based on the acquired difference.

As a result, when the photographing device 3 photographs video including the photographing location time information Tp displayed on the transmitting side time information display device 200, the time difference acquisition unit 300 can acquire the difference between the photographing location time information Tp displayed on the transmitting side time information display device 200 and the separated location time information acquired at the separated location. If the difference between the acquired photographing location time information Tp and the separated location time information is large, the blinking cycle adjustment unit 26B can adjust the blinking cycle of the marker light to accurately determine the video transmission delay time Td.

(10) A video transmission delay time measurement system 1D according to a tenth aspect is any one of the video transmission delay time measurement systems 1D described in (1) to (9), in which the image capture device 3 and the blinking marker 4 are movable relative to each other so as to return to their fixed positions in accordance with the blinking cycle of the blinking marker 4.

As a result, when the camera device 3 and the blinking marker 4 are moved relative to each other so that they return to their home positions in sync with the blinking cycle of the blinking marker 4, if the camera device 3 and the blinking marker 4 are operating normally, the camera device 3 positioned in its home position can capture the blinking of the blinking marker 4. If at least one of the camera device 3 and the blinking marker 4 is not operating normally, the camera device 3 will not be able to capture the blinking of the blinking marker 4 normally. Therefore, it is easy to determine whether the camera device 3 and the blinking marker 4 are operating normally.

(11) The video transmission delay time measurement method according to the eleventh aspect includes step S11 of receiving a GPS signal at a shooting location, step S12 of transmitting a transmitting side reference signal Sg1 synchronized with the received GPS signal, step S13 of periodically flashing a marker light based on the transmitting side reference signal Sg1, step S14 of shooting a video including the subject and the flashing marker 4 at the shooting location, step S15 of transmitting data of the shot video, step S21 of receiving the video data at a remote location away from the shooting location, and step S22 of transmitting the received video data. The method includes step S22 of displaying an image based on the detected data, step S23 of detecting blinking of the marker light in the displayed image, step S24 of receiving a GPS signal at the remote location, step S25 of transmitting a receiving-side reference signal Sg2 synchronized with the GPS signal received at the remote location, and step S26 of outputting information regarding the image transmission delay time Td from when the image is captured by the image capturing device 3 to when it is displayed on the display device 6, based on the detected blinking signal Sgm indicating the blinking state of the marker light and the receiving-side reference signal Sg2.

This video transmission delay time measurement method makes it possible to measure the video transmission delay time while actually shooting video.

DESCRIPTION OF SYMBOLS 1A to 1D...Video transmission delay time measuring system 2...Transmitting unit 3...Photographing device 3a...Range 4...Blinking markers 4m, 4mB, 4mG, 4mR...Marker light 5...Receiving unit 6...Display device 7...First blinking detection unit 8...Receiving side blinking markers 8m, 8mB, 8mG, 8mR...Marker light 20...Transmitting side controller 21...Photographing control unit 22...Marker control unit 23...Transmitting side GPS signal receiving unit 24...Transmitting side reference signal transmitting unit 25...Data transmitting units 26A, 26B...Blinking period adjusting unit 31...Fixing member 50 ...Receiving side controller 51...Data receiving unit 52...Display control unit 53...Receiving side GPS signal receiving unit 54...Receiving side reference signal transmitting unit 55...Delay time information output unit 56A...Delay time abnormality determination unit 58...Fault diagnosis unit 72...Second blinking detection unit 100...Network 200...Transmitting side time information display device 300...Time difference acquisition unit 301...Camera Sg1...Transmitting side reference signal Sg2...Receiving side reference signal Sgm...Blinking signal Sgr...Blinking signal T...Photographed object Td...Video transmission delay time Tp...Photographing location time information

Claims (11)

A transmitting unit is disposed at a photographing location, and a receiving unit is disposed at a remote location away from the photographing location,
The transmitting unit
a transmitting-side GPS signal receiving unit that receives a GPS (Global Positioning System) signal at the photography location;
a transmitter-side reference signal transmitter that transmits a transmitter-side reference signal synchronized with the GPS signal received by the transmitter-side GPS signal receiver;
a blinking marker that periodically blinks a marker light based on the transmitting side reference signal;
a photographing device that photographs an image including a photographing target and the blinking marker at the photographing location;
a data transmission unit that transmits data of the video captured by the imaging device,
The receiving unit:
a data receiving unit that receives the video data;
a display device that displays an image based on the received image data;
a first blinking detection unit that detects blinking of the marker light in the image displayed on the display device;
a receiving-side GPS signal receiving unit that receives a GPS signal at the remote location;
a receiving-side reference signal transmitting unit that transmits a receiving-side reference signal synchronized with the GPS signal received by the receiving-side GPS signal receiving unit;
a delay time information output unit that outputs information regarding the video transmission delay time from when the video is captured by the imaging device to when it is displayed on the display device, based on a blinking signal indicating the blinking state of the marker light detected by the first blinking detection unit and the receiving side reference signal. the transmitting-side reference signal and the receiving-side reference signal are pulse signals whose signal states change at predetermined time intervals,
the blinking signal is a waveform signal that indicates switching of a signal state in response to lighting and extinguishing of the blinking marker;
2. The video transmission delay time measuring system according to claim 1. The delay time information output unit
The video transmission delay time measuring system according to claim 2, further comprising an oscilloscope that displays the receiving side reference signal and the blinking signal side by side. The delay time information output unit
4. The video transmission delay time measuring system according to claim 2, wherein information about the video transmission delay time is output based on a timing at which the signal state of the receiving side reference signal changes and a timing at which the signal state of the blinking signal changes. The delay time information output unit
5. The video transmission delay time measuring system according to claim 4, wherein the video transmission delay time is calculated based on the timing at which the signal state of the receiving side reference signal changes and the timing at which the signal state of the blinking signal changes, and the calculated value of the video transmission delay time is output. The video transmission delay time measuring system according to claim 1 or 2, further comprising a fixing member for fixing the blinking marker and the image capturing device. The transmitting unit
The video transmission delay time measuring system according to claim 1 or 2, further comprising a blinking cycle adjusting unit that adjusts the blinking cycle of the marker light of the blinking marker. The receiving unit:
a receiving-side blinking marker that periodically blinks a marker light based on the receiving-side reference signal;
a second blinking detection unit that detects blinking of the marker light of the receiving side blinking marker,
the blinking marker and the receiving-side blinking marker are each capable of blinking a plurality of types of the marker light in the same sequence,
The video transmission delay time measuring system according to claim 7, wherein the blinking cycle adjustment unit adjusts the blinking cycle of the marker light of the blinking marker based on the type of the marker light of the blinking marker detected by the first blinking detection unit and the type of the marker light of the receiving side blinking marker detected by the second blinking detection unit. the transmitting unit further includes a transmitting-side time information display device that displays the photographing location time information at the photographing location based on external time information distributed from an external time information output unit;
the photographing device photographs the image including the photographing location and time information displayed on the transmitting side time information display device,
The receiving unit:
the photographing location and time information displayed on the display device;
a time difference acquisition unit that acquires a difference between remote location time information based on external time information distributed from an external time information output unit and remote location time information acquired at the remote location,
The video transmission delay time measuring system according to claim 7 , wherein the blinking cycle adjusting unit adjusts the blinking cycle of the marker light of the blinking marker based on the acquired difference. 3. The video transmission delay time measuring system according to claim 1, wherein the image capturing device and the blinking marker are movable relative to each other so as to return to a fixed position in accordance with the blinking cycle of the blinking marker. receiving a GPS signal at a photography location;
transmitting a transmitter reference signal synchronized with the received GPS signal;
a step of periodically blinking a marker light by a blinking marker based on the transmitting side reference signal;
A step in which an image capturing device captures an image including a subject and the blinking marker at the image capturing location;
transmitting data of the video captured by the imaging device;
receiving the image data at a remote location away from the shooting location;
a step of displaying an image based on the received image data by a display device;
detecting blinking of the marker light in the displayed image;
receiving a GPS signal at the remote location;
transmitting a receiver reference signal synchronized with the GPS signal received at the remote location;
and outputting information regarding the video transmission delay time from when the video is captured by the imaging device to when it is displayed on the display device, based on a blinking signal indicating the blinking state of the detected marker light and the receiving-side reference signal.