WO2018180200A1

WO2018180200A1 - Monitoring system and monitoring method

Info

Publication number: WO2018180200A1
Application number: PCT/JP2018/008015
Authority: WO
Inventors: 辰行澤野
Original assignee: 株式会社日立国際電気
Priority date: 2017-03-28
Filing date: 2018-03-02
Publication date: 2018-10-04
Also published as: JP6781822B2; JPWO2018180200A1

Abstract

The present invention relates to technology for staggering the exposure times of each of a plurality of cameras, thereby preventing photographing omission of an event that occurs outside the exposure time, and the purpose thereof is to enable an event occurring in an instant to be more reliably photographed. This monitoring system is characterized by being provided with: a plurality of cameras that photograph an object to be monitored; a control unit that controls the plurality of cameras such that the exposure times of the plurality of cameras are continuous without omission; and a video recording unit that records, as continuous videos, videos taken by the plurality of cameras on the basis of time information.

Description

Monitoring system and monitoring method

The present invention relates to a technique for shifting the exposure time of each camera in a plurality of cameras and preventing an omission of shooting of an event occurring outside the exposure time.

In recent years, the number of objects to be monitored by a surveillance camera is increasing due to the improvement of camera performance and the improvement of video processing technology. Among them, there is a need to monitor wheels and pantographs as the state of the train.
When monitoring a pantograph abnormality by installing a camera on a running train, it is also necessary to take an image of the arc generated between the pantograph and the overhead line. Since an excessive arc is a manifestation of an abnormality, it is required to image the arc when monitoring a pantograph.
In the following prior art document, in order to accurately photograph a subject with a large gradation width between bright and dark portions, the signal level from the image sensor of the camera changes temporally and periodically regardless of subject illuminance. Thus, a technique for changing the aperture and shutter speed is described.

Japanese Patent Laid-Open No. 2005-094814

Here, since the arc of the pantograph is instantaneous, it may not be possible to shoot depending on the timing of the occurrence, and it is now known that the arc was generated for the first time when the shoot was possible. The reason why photography is not possible is that an arc occurred outside the exposure time of the camera.
Describing in detail with reference to FIG. 8, the camera repeats the operation of closing the shutter after a predetermined exposure time and moving to the next exposure time. Since the arc indicated by symbol A emitted during the exposure time, it can be taken with a camera. On the other hand, the arc indicated by the symbol B emits light outside the exposure time and cannot be photographed by the camera. As described above, according to the conventional technique, when an excessive arc occurs outside the exposure time, the excessive arc may not be photographed and may be overlooked. As a result, damage to the pantograph is not noticed, leading to an influence on the running of the train.
Although the pantograph arc was given as an example of an event that occurs instantaneously, this is not the only case, and there are sparks between the train wheels and rails, not only in the train but also in situations where sparks occur when metals touch each other, A similar problem occurs when monitoring a scene where a spark is generated due to a potential difference between two objects or various scenes where an electric discharge is generated between two poles and an arc is generated.
Accordingly, an object of the present invention is to make it possible to more reliably capture an event that occurs in an instant as described above.

The monitoring system of the present invention includes a plurality of cameras that shoot a monitoring target, a control unit that controls the plurality of cameras so that the exposure times of the plurality of cameras are continuous and continuous, and images of the plurality of cameras as time information. And a video recording unit that records the video as a continuous video.

In addition, the image processing unit further includes an image processing unit that calculates an average luminance value of a predetermined region of the images of the plurality of cameras and notifies the control unit of alarm information when the predetermined luminance is equal to or greater than a preset threshold, and the control unit receives the received alarm It is preferable to record the information together with the video in the video recording unit.

Further, it is preferable that the image processing unit transmits the calculated average luminance value to the control unit, and the control unit records the average luminance value together with the video in the video recording unit.

Further, it is preferable to further include a display unit that displays the video recorded in the video recording unit together with information on the average luminance value.

In addition, it is preferable that a plurality of cameras are installed on the train so as to photograph a pantograph of the train.

Also, it is preferable that the control unit obtains the train position information when the video is shot and records it in the video recording unit together with the video.

Furthermore, the monitoring method of the present invention is a monitoring method for monitoring a pantograph of a train, wherein the exposure times of a plurality of cameras are controlled so that the exposure times of a plurality of cameras are continuous and photographed by the plurality of cameras. The recorded video is recorded in the video storage unit as a continuous video based on the time information.

According to the present invention, an event that occurs in an instant, such as the occurrence of an arc, can be captured more reliably.

It is a figure for demonstrating the principle of the monitoring system which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the monitoring system which concerns on one Embodiment of this invention. It is a figure for demonstrating the process of the image processing control part of the monitoring system which concerns on one Embodiment of this invention. It is a figure for demonstrating the process of the monitoring system which concerns on one Embodiment of this invention. It is a figure which shows the example of a screen display of the monitoring system which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the monitoring system which concerns on other one Embodiment of this invention. It is a figure for demonstrating the process of the monitoring system which concerns on other one Embodiment of this invention. It is a figure for demonstrating the conventional problem.

An embodiment of the present invention will be described below with reference to the drawings.
Example 1
First, the principle of a monitoring system according to an embodiment of the present invention will be described. As shown in FIG. 1, the arc A can be taken with one camera 1, but the arc B outside the exposure time cannot be taken. Therefore, by assigning the time outside the exposure time of the camera 1 to the exposure time of another camera 2, the time outside the exposure time seen in the entire system is eliminated. This makes it possible to always take a pantograph.

FIG. 2 shows a configuration example of a monitoring system as one embodiment of the present invention.
Cameras 1 to 3 are installed on the upper part of the roof of the train and photograph the contact portion between the pantograph and the overhead line. The cameras 1 to 3 preferably shoot the entire pantograph. The cameras 1 to 3 may be arranged in the same direction with respect to the pantograph, or may be installed so as to shoot from different directions.

The HUB 11 is a device that relays / transfers data on a network to devices connected by a LAN (Local Area Network) cable.
The encoders 12 to 14 are devices that convert communication between the cameras 1 to 3 and other devices and convert the video of the camera into a network, respectively.
The image processing control unit 15 is a device that detects the occurrence of an excessive arc by recognizing the luminance in the screen by image processing when an arc is generated in the pantograph being photographed.

As shown in FIG. 3, the image processing control unit 15 presets a region of interest X in which the contact portion between the pantograph and the overhead line in the photographed image is photographed for each of the cameras 1 to 3. A luminance value for each pixel is detected, and an average luminance value of the region of interest X is calculated for each frame or for each predetermined frame. When the calculated average luminance value is equal to or greater than a preset threshold value, the image processing control unit 15 determines that an excessive arc has occurred and notifies the control unit 16 of alarm information.
In addition, the image processing control unit 15 transmits the calculated average luminance value to the control unit 16.

The control unit 16 is a control unit that controls the entire monitoring system, and controls a synchronization signal generator 17 (to be described later) so as to shift the exposure times of a plurality of cameras installed. That is, the control unit 16 controls the plurality of cameras 1 to 3 so that the exposure times of the plurality of cameras 1 to 3 are continuous with no omission. Specifically, the control signal is transmitted to the synchronization signal generator 18.
Further, the control unit 16 receives alarm information (excessive arc detection information) from the image processing control unit 15 and issues a recording instruction to the network digital recorder 17 described later. The control unit 16 is realized by a CPU or a personal computer, for example.

A network digital recorder (NDR in the figure, registered trademark) 17 receives the alarm of occurrence of an excessive arc from the control unit 16 and records the images of the cameras 1 to 3. Further, the NDR 17 rearranges the frames of the cameras 1 to 3 in order of time and composes them into one video. That is, the NDR 17 records the videos from the plurality of cameras 1 to 3 as continuous videos based on the time information.
Further, the NDR 17 always records video from the cameras 1 to 3, and when receiving an alarm of occurrence of an excessive arc from the control unit 16, a storage unit for recording the synthesized video from a preset predetermined time before Write to. The storage unit for recording may be, for example, a removable storage device, such as a solid state drive (SSD) or a hard disk drive (HDD).

The synchronization signal generator 18 receives control from the control unit 16 and controls the plurality of cameras 1 to 3 so that the exposure time is shifted. Specifically, signals for controlling the exposure time, shutter timing, etc. are transmitted to the cameras 1 to 3, respectively.
The office PC (Personal computer) 19 extracts the recorded data from the NDR from the NDR using the removable storage device or an external medium such as a USB (Universal Serial Bus) memory, and records the excessive data. This is to check the video when the arc occurs.

Here, the processing operation of the present monitoring system will be described with reference to FIG.
The control unit 16 controls the synchronization signal generator 17 so that the exposure time of the installed cameras 1 to 3 is shifted so that the cameras 1 to 3 do not overlap each other and the synchronization signal is transmitted.
Under the control of the control unit 16, the synchronization signal generator 17 transmits a synchronization signal to the cameras 1 to 3 so that the exposure time is shifted. Here, the exposure time is set to 1/100 sec (every 10 ms) at 1/30 sec (about 33.3 ms) of the video, and the exposure times of the cameras 1 to 3 are set so as not to overlap each other within about 33.3 ms. As a result of this processing, the exposure times of the cameras 1 to 3 do not overlap, so that the system loses the time outside the exposure time and does not fail to record the moment of arc occurrence. That is, the arc A cannot be taken by the

cameras

1 and 3, but can be taken by the camera 2. The arc B cannot be taken by the

cameras

1 and 2, but can be taken by the camera 3.

Time information is added to the images taken by the cameras 1 to 3 by the encoders 12 to 14, respectively. The NDR 17 rearranges the images based on the time information of the videos and combines them into one video. Thereby, for example, when the recorded video of the NDR 17 is browsed by the control unit 16, it is displayed as one video. When the recorded video is extracted by an external medium and viewed on the office PC 19, it is displayed as one video in the same manner.

Further, the control unit 16 can store the average brightness value calculated by the image processing control unit 15, information about the train as train operation information, GPS (Global Positioning System) position information, and the like in the NDR 17 together with the video. preferable. As a result, the average luminance value at the time of video shooting and the interval information are linked and stored in the NDR 17. Therefore, when displaying the video of the NDR 17 directly or taking out, the time, average luminance value, interval information, and GPS position information stored in association with the video can be displayed together with the video. Furthermore, it is possible to search for an image based on the time, average luminance value, interval information, and GPS position information.

Next, a display example on the office PC 19 will be described with reference to FIG. FIG. 5 shows an example in which the video taken out from the NDR 17 is displayed on the display unit 19a of the office PC 19. A video is displayed in the center of the screen 17a, and the search condition 17c when the search is performed with the operation icon 17b is displayed together with the video. Further, the screen 17a is provided with a luminance value display area 17d for displaying an average luminance value of the displayed video with an indicator. Thus, the user can grasp not only the actual video but also the average luminance value at this time by the indicator, and can easily recognize the abnormal state. Note that the display method of the average luminance value information is not limited to the example of FIG. 5, and the value itself may be displayed.

As described above, according to the present embodiment, since the occurrence of an excessive arc of a pantograph can be reliably photographed, damage to the pantograph and the overhead line can be inspected in advance. Thereby, the safety state of the train can be maintained.

Note that when the controller 16 changes the exposure time (shutter speed) of the cameras 1 to 3 from 1/100 sec to 1/30 sec (33.3 ms) in FIG. 4, exposure is performed for the time of one frame of video. The other two cameras no longer need to compensate outside the exposure time. The next frame is shot by another camera, and the camera is switched. If the shutter speed is 1/60 sec (16.7 ms), one frame of video can be shot with two cameras. Thus, the control unit 16 may change the setting of the exposure time (shutter speed) of the cameras 1 to 3. In this case, the control unit 16 controls the NDR 17 to change the number of cameras to be recorded from three to one or two. That is, the control unit 16 controls the number of cameras that record video on the NDR 17 in accordance with the exposure time (shutter speed) set for the cameras 1 to 3. As a result, the number of cameras to be recorded can be reduced, the storage period of the recorded video can be extended, and the network load can be reduced.

(Example 2)
Next, another embodiment of the present invention will be described with reference to FIGS.
FIG. 6 shows a configuration example of a monitoring system as another embodiment of the present invention.
6 differs from FIG. 2 in the camera 1a and the camera 3a.
The camera 1a is equipped with an image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) that has a short time from the exposure until the video signal is output. It has a function of outputting a signal.
The camera 3a can capture a high brightness subject such as an arc without saturating the signal by inputting the high brightness detection signal output from the camera 1a as an exposure signal.

Here, the processing operation of another embodiment of the monitoring system will be described with reference to FIG.
When the exposure is started, the camera 1a starts outputting a video signal after 1H (scanning line), and outputs an exposure signal as a high-intensity detection signal to the camera 3a when a high-intensity signal such as an arc is detected.
The camera 3a performs exposure based on the exposure signal output from the camera 1a, and outputs an image signal after one field. The camera 3a does not output an image signal unless an exposure signal is input.
If the level of a high luminance signal such as an arc is known to some extent, the exposure time may be determined in advance using the exposure signal output from the camera 1a as a trigger signal.
The monitoring system of this example can shoot a subject including high luminance with the camera 1a, and can shoot a high luminance subject such as an arc without saturating the signal with the camera 3a.

The monitoring system according to the embodiment of the present invention can capture an event that occurs in an instant, such as the occurrence of an arc, more reliably.

As mentioned above, although one embodiment of the present invention was described in detail, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the case where the monitoring system captures the contact portion between the pantograph and the overhead line of the vehicle and monitors the arc has been described as an example. However, the present invention is not limited to the application to the arc of a pantograph, and as described in the problem column to be solved by the invention, monitors events that occur instantaneously outside the camera exposure time and cannot be photographed. Can be applied to all.

The present invention can also be provided, for example, as a method or method for executing the processing according to the present invention, a program for realizing such a method or method, or a storage medium for storing the program.
As an example, the image processing control unit 15 and the control unit 16 may be realized by executing a predetermined program on a computer. That is, for example, the processor of the computer constituting the image processing control unit 15 or the control unit 16 reads out a program stored in a data storage device such as a hard disk or a flash memory and executes the program, thereby controlling the image processing. The unit 15 and the control unit 16 may be realized.

As described above, the monitoring system and the monitoring method of the present invention have the following features, for example.
A plurality of cameras that shoot the monitoring target, a control unit that controls the plurality of cameras so that the exposure times of the plurality of cameras are continuous without omissions, and images of the plurality of cameras that are continuous based on time information A surveillance system comprising a video recording unit that records video.

An average luminance value of a predetermined area of the images of the plurality of cameras is calculated, and further includes an image processing unit that notifies the control unit of alarm information when the predetermined luminance is equal to or higher than a preset threshold, and the control unit receives The monitoring system according to claim 1, wherein the alarm information is recorded together with the video in the video recording unit.

The monitoring system, wherein the image processing unit transmits the calculated average luminance value to the control unit, and the control unit records the average luminance value together with the video in the video recording unit.

The monitoring system according to claim 1, further comprising a display unit for displaying the video recorded in the video recording unit together with the information on the average luminance value.

The monitoring system, wherein the plurality of cameras are installed in the train so as to take a pantograph of the train.

The monitoring system according to claim 1, wherein the control unit acquires position information of the train when the video is shot, and records the train information together with the video in the video recording unit.

A monitoring method for monitoring a pantograph of a train, wherein the exposure times of the plurality of cameras are controlled so that the exposure times of the cameras are continuous without omission, and images taken by the plurality of cameras are based on time information It is characterized by being recorded in the video storage unit as a continuous video.

The present invention can be used in a monitoring system that captures an instantaneous event such as an arc.

1, 2, 3, 1a, 3a: camera, 11: HUB, 12, 13, 14: encoder, 15: image processing control unit, 16: control unit, 17: NDR, 18: synchronization signal generator, 19: office work PC.

Claims

A plurality of cameras for shooting the monitoring target;
A controller that controls the plurality of cameras so that the exposure times of the plurality of cameras are continuous without omissions;
A monitoring system comprising: a video recording unit that records video from the plurality of cameras as continuous video based on time information.
An image processing unit that calculates an average luminance value of a predetermined area of the images of the plurality of cameras and notifies the control unit of alarm information if the average luminance value is greater than or equal to a preset threshold;
The monitoring system according to claim 1, wherein the control unit records the received alarm information together with the video in the video recording unit.
The image processing unit transmits the calculated average luminance value to the control unit,
The monitoring system according to claim 2, wherein the control unit records the average luminance value together with the video in the video recording unit.
4. The monitoring system according to claim 3, further comprising a display unit for displaying the video recorded in the video recording unit together with the information on the average luminance value.
The monitoring system according to claim 1, wherein the plurality of cameras are installed in the train so as to photograph a pantograph of the train.
The monitoring system according to claim 5, wherein the control unit acquires position information of the train when the video is shot and records the train information together with the video in the video recording unit.
A monitoring method for monitoring a pantograph of a train,
Controlling the exposure times of the plurality of cameras so that the exposure times of the plurality of cameras are continuous without omissions,
A monitoring method, wherein videos taken by the plurality of cameras are recorded in a video storage unit as continuous videos based on time information.