Monitoring system

Abstract

The system will automatically adjust the frame rate, bitrate, and compression ratio of the forward-facing camera according to the train's operating conditions. [Solution] When the train starts moving, the system controls the forward camera 13 by increasing its frame rate from "low" to "medium", increasing its bitrate from "low" to "medium", and decreasing its compression ratio from "high" to "low" (state B → state A). Furthermore, if the system analyzes the video footage from the forward camera 13 while the train is moving and detects an obstacle in the video footage from the forward camera 13, it further controls the forward camera 13 by increasing its frame rate from "medium" to "high", increasing its bitrate from "medium" to "high", and decreasing its compression ratio from "medium" to "low" (state A → state S).

Description

Technical Field

[0001] Relates to a monitoring system having a plurality of cameras mounted on a train.

Background Art

[0002] In the operation of railway vehicles, on lines with few passengers and short train formations in operation, single-person operation by a driver is adopted. Amid the trend of a decreasing number of railway employees due to population dynamics associated with a declining working population, each railway operator is adopting a policy of increasing the lines and the number of cars in the formation to which single-person operation is applied. However, increasing the number of cars in the formation increases the burden of safety confirmation work for a single driver, raising concerns that accidents are likely to occur due to oversight.

[0003] In recent years, in order to reduce the burden of safety confirmation work for drivers, monitoring systems have been developed that enable drivers to visually confirm the situation of passengers boarding and alighting from the train by displaying the images of door cameras attached near the doors of each vehicle of the train on a display device in the driver's cab. In addition, monitoring systems have also been developed that enable the monitoring of the situation in the passenger compartment with in-car cameras that photograph the inside of the train. Furthermore, a monitoring system has also been considered that mounts a front camera for photographing the direction of travel of the train on the leading vehicle and records the images of the front camera. The recorded images of the front camera can be used for various purposes, such as post-accident confirmation of obstacles in front of the train and as a reference during maintenance work.

[0004] Examples of the prior art in the technical field to which the present invention pertains are as follows. For example, Patent Document 1 discloses an invention that controls the frame rate and image quality of a door camera that photographs the periphery of a train door according to the speed state of the train or the open / closed state of the door.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In surveillance systems with video recording capabilities, such as those using forward-facing cameras, the storage capacity of the recording device is finite. Therefore, to extend the recording period as much as possible, the video to be recorded must have a low frame rate, low bitrate, and high compression ratio. From the perspective of network load, it is also desirable for the video to be recorded to have a low frame rate, low bitrate, and high compression ratio. However, because sufficient visibility cannot be obtained with video at a low frame rate, low bitrate, and high compression ratio, it may not be possible to properly confirm obstacles in front of the train after they have occurred.

[0007] This invention has been made in view of the above-mentioned conventional circumstances, and aims to enable the automatic adjustment of the frame rate, bitrate, and compression ratio of the forward camera according to the conditions while the train is running. [Means for solving the problem]

[0008] A monitoring system according to one aspect of the present invention is a monitoring system having a plurality of cameras mounted on a train, wherein one of the plurality of cameras is a forward camera mounted on the leading car and taking pictures of the area in front of the car, and the system includes a control device that changes at least one of the frame rate, bit rate, and compression ratio of the forward camera according to the running state of the train.

[0009] In the above-described monitoring system, the control device may be configured to transmit a control signal to the forward camera instructing it to increase the frame rate, increase the bit rate, or decrease the compression ratio of the forward camera in response to the train starting to move.

[0010] Furthermore, in the above-described monitoring system, the control device may be configured to change at least one of the frame rate, bitrate, and compression ratio of the forward camera in accordance with the results of the analysis of the video footage captured by the forward camera obtained while the train is in motion.

[0011] Furthermore, in the above-described monitoring system, the control device may be configured to transmit a control signal to the forward camera instructing it to increase the frame rate, increase the bitrate, or decrease the compression ratio of the forward camera in response to the detection of a predetermined obstacle from the image captured by the forward camera obtained while the train is in motion.

[0012] Furthermore, in the above-described monitoring system, the control device may be configured to transmit a control signal to the forward camera instructing it to increase the frame rate, increase the bitrate, or decrease the compression ratio of the forward camera in response to the detection of another train from the forward camera's video footage obtained while the train is in motion.

[0013] Furthermore, in the above-described monitoring system, the control device may be configured to transmit a control signal to the forward camera instructing it to increase the frame rate, increase the bitrate, or decrease the compression ratio of the forward camera in response to the detection of a moving object in a direction crossing the direction of travel of the train from the image captured by the forward camera obtained while the train is in motion.

[0014] Furthermore, in the above-described monitoring system, the control device may be configured to transmit a control signal to the forward camera instructing it to increase the frame rate, increase the bitrate, or decrease the compression ratio of the forward camera in response to an abnormality detected by comparing the image captured by the forward camera obtained while the train is running with a pre-prepared reference image. [Effects of the Invention]

[0015] According to the present invention, it becomes possible to automatically adjust the frame rate, bit rate, and compression ratio of the front camera according to the situation during the train's operation.

Brief Description of the Drawings

[0016] [Figure 1] It is a diagram showing a configuration example of a monitoring system according to an embodiment of the present invention. [Figure 2] It is a diagram showing an example of the transition of the operating state of the camera during normal operation. [Figure 3] It is a diagram showing an example of the transition of the operating state of the camera when an obstacle is detected during train operation. [Figure 4] It is a diagram showing an example of the transition of the operating state of the camera when a dangerous event is detected during boarding and alighting. [Figure 5] It is a diagram showing an example of the transition of the operating state of the camera when the emergency reporting button is pressed during train operation.

Modes for Carrying Out the Invention

[0017] An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration example of a monitoring system according to an embodiment of the present invention. The train shown in FIG. 1 is composed of four cars, cars 10-1 to 10-4, but the number of cars in the train formation is arbitrary.

[0018] Each car 10-1 to 10-4 of the train is provided with a door camera 11, an in-car camera 12, a relay device 14, and an emergency reporting device 18. In addition, the front camera 13, the display device 15, the control device 16, and the recording device 17 are further provided in the cars 10-1 and 10-4 at both ends of the train.

[0019] The relay device 14 is a communication device for constructing an in-train network. For example, a switching hub is used. The relay devices 14 in each car 10-1 to 10-4 are communicably connected to the devices and apparatuses mounted on that car by cables or the like, and are also communicably connected to the relay devices 14 of adjacent cars by cables or the like.

[0020] The door camera 11 is an imaging device provided outside the vehicle so as to photograph the vehicle door and its surroundings from outside the vehicle. In FIG. 1, there are a door camera 11(A) installed on the rear side of the vehicle facing the train running direction and a door camera 11(B) installed on the front side of the vehicle facing the opposite direction of the train running direction, but this is merely an example.

[0021] The in-vehicle camera 12 is an imaging device provided inside the vehicle so as to photograph the interior of the passenger compartment. The in-vehicle camera 12 may be arranged so as to easily photograph the vicinity of the door in the passenger compartment, or may be arranged so as to easily photograph the state of the passengers in the passenger compartment.

[0022] The front camera 13 is an imaging device provided on the leading vehicle 10-1 (and the trailing vehicle 10-4) so as to photograph the front in the train running direction. The front camera 13 may be provided outside the vehicle so as to directly photograph the state in front of the leading vehicle, or may be provided inside the vehicle so as to photograph the state in front of the leading vehicle through the windshield from the driver's cab.

[0023] The display device 15 displays the images of the door cameras 11 of each vehicle while the train is stopped at a station. Therefore, the train driver can visually confirm the state of the passengers boarding and alighting the train on the spot. The display device 15 may further display the images of the door cameras 11 of each vehicle even when the train is running through the section of the station platform (hereinafter simply referred to as "platform"). In this example, it is assumed that only the display device 15 of the leading vehicle (for example, vehicle 10-1) in the train running direction is operated, but it is also possible to additionally operate the display device 15 of the trailing vehicle 10-4 and let another crew member confirm it. <00001​​

[0025] The control device 16 performs various controls related to the display of the display device 15, such as turning the display ON / OFF and switching the camera images to be displayed, based on vehicle information obtained from the vehicle or a higher-level system. Examples of vehicle information include speed information indicating the train's running speed and location information indicating the train's current position. For location information, mileage information or GPS (Global Positioning System) information can be used. Vehicle information may be provided to the control device 16 via contact input or via LAN input. The control device 16 can also perform various controls related to the display of the display device 15 in response to instructions from the driver to the operation unit of the display device 15.

[0026] The control device 16 is implemented, for example, by a computer equipped with hardware resources such as a processor and memory, and is configured to realize functions and processes related to the present invention by reading a predetermined program from memory and executing it using the processor. The control device 16 may be implemented by a single computer, or by multiple computers operating in cooperation.

[0027] The recording device 17 records video footage (i.e., records video data) captured by the cameras in each vehicle (door camera 11, interior camera 12, and front camera 13). The video footage recorded by the recording device 17 can be used for various purposes, such as post-incident safety checks of train operations and as reference during maintenance work.

[0028] The main feature of the monitoring system in this example is that the control device 16 is configured to control the shooting parameters of the cameras in each vehicle according to the train's running status, etc. Examples of shooting parameters include frame rate, bitrate, and compression ratio. The control of the shooting parameters of the cameras in each vehicle will be explained below with reference to Figures 2 to 5.

[0029] Here, the operating status of the cameras on each vehicle will be managed in three stages: "A," "B," and "S." Operating status A is the standard medium-quality video shooting mode, with settings of "medium" frame rate, "medium" bitrate, and "medium" compression ratio. Operating status B is the low-quality video shooting mode, with settings of "low" frame rate, "low" bitrate, and "high" compression ratio. Operating status S is the high-quality video shooting mode, with settings of "high" frame rate, "high" bitrate, and "low" compression ratio.

[0030] First, the changes in the camera's operating state during normal operation will be explained with reference to Figure 2. In Figure 2, the train's running state is divided into four categories: "running," "approaching the platform," "stopped," and "moving out of the platform." "Running" is the state when the train is running in a section outside the station platform. "Approaching the platform" is the state when the train is approaching the station platform and decelerating. "Stopped" is the state when the train is stopped at the station platform (including during passenger boarding and alighting and before the train departs). "Moving out of the platform" is the state when the train has started moving and is moving out of the station platform.

[0031] These running conditions can be determined using platform detection sensors (front) installed on the leading car, platform detection sensors (rear) installed on the last car, a speed signal indicating whether the train speed is 5 km / h or less, a door signal indicating whether the doors are open or closed, and operation signals from the master controller that controls the train's power (acceleration) and braking. For example, the period before the station platform is detected by the platform detection sensor (front) is defined as "running," the period from when the station platform is detected until the train speed is 5 km / h or less and the doors are open is defined as "approaching the platform," the period from when the train speed is 5 km / h or less and the doors are open until the doors are closed and the notch is turned on (acceleration begins) is defined as "stopped," the period from when the doors are closed and the notch is turned on until the station platform is no longer detected by the platform detection sensor (rear) is defined as "approaching the platform," and the period after the station platform is no longer detected is defined as "running." Note that the above classification of running conditions and the method of determining them are examples and are not limited to these.

[0032] Door camera 11 applies operating state B (low frame rate, low bitrate, high compression ratio) to capture low-quality video when the train is "in motion," and applies operating state A (medium frame rate, medium bitrate, medium compression ratio) to capture medium-quality video otherwise. In-car camera 12 applies operating state B (low frame rate, low bitrate, high compression ratio) to capture low-quality video regardless of the train's movement. Front camera 13 applies operating state B (low frame rate, low bitrate, high compression ratio) to capture low-quality video when the train is "stopped," and applies state A (medium frame rate, medium bitrate, medium compression ratio) to capture medium-quality video otherwise.

[0033] Such control can be achieved, for example, by the control device 16 sending a control signal to each vehicle's camera that includes setting values ​​for shooting parameters such as frame rate, bitrate, and compression ratio, and by each vehicle's camera changing the shooting parameters according to the control signal. Alternatively, the setting values ​​for the shooting parameters to be applied in each of the operating states A, B, and S can be stored in advance in each camera, and the control device 16 can send a control signal to each vehicle's camera instructing it to switch operating states, and by each vehicle's camera switching operating states (changing shooting parameters) according to the control signal.

[0034] Figure 3 shows an example of the camera state transition when an obstacle is detected while the train is in motion. As explained with reference to Figure 2, when the train is "in motion," the forward camera 13 is in operating state A and is capturing medium-quality video. During this time, the control device 16 analyzes the video captured by the forward camera 13 and determines whether or not an obstacle exists in front of the train. If an obstacle is detected in front of the train as a result, the control device 16 controls the forward camera 13 to switch to operating state S (high frame rate, high bitrate, low compression ratio) so that high-quality video of the obstacle in front of the train can be captured, as shown in Figure 3. Then, for example, after a predetermined time has elapsed, the control device 16 controls the forward camera 13 to automatically return to its original operating state. This allows high-quality video of the obstacle in front of the train (smooth and clear video) to be recorded in the recording device 17, making it easier to perform tasks such as post-incident situation confirmation.

[0035] Here, the video footage captured by the forward camera 13 can be analyzed using various methods. For example, by processing the video footage from the forward camera 13 to detect images of obstacles that have been registered in advance, it is possible to determine that an obstacle exists in front of the train if an object with a similarity to the registered obstacles that exceeds a certain threshold is detected. Alternatively, it is also possible to determine that an obstacle exists in front of the train by analyzing the video footage from the forward camera 13 using a learning model that has been pre-trained on obstacles.

[0036] Furthermore, the forward camera 13 may be switched to operating state S even in situations other than those described above. For example, if another train is detected in the video footage captured by the forward camera 13 while the train is in motion, the forward camera 13 may be switched to operating state S to capture high-quality video. This allows high-quality video footage of the situation when passing another train to be recorded in the recording device 17.

[0037] Furthermore, if a moving object crossing the direction of the train's movement is detected from the video footage captured by the forward camera 13 while the train is in motion, the forward camera 13 is switched to operating state S to capture high-quality video. This allows high-quality video of the object that obstructed the train's movement, or an object that potentially obstructed it, to be recorded in the recording device 17.

[0038] Furthermore, if an abnormality is detected by comparing the video footage captured by the forward camera 13 while the train is in motion with a pre-prepared reference video, the forward camera 13 is switched to operating state S to capture high-quality video. In this case, multiple reference videos corresponding to shooting conditions such as the time of day, season, and weather when the train is running may be prepared, and the reference video to be used may be switched based on the comparison according to the shooting conditions during operation. This makes it possible to record high-quality video in the recording device 17 in the event of any unexpected abnormality.

[0039] Figure 4 shows an example of the camera state transition when a dangerous event is detected during boarding or alighting. As explained with reference to Figure 2, when the train is "stopped", the door camera 11 is in operating state A and is capturing medium-quality video. During this time, the control device 16 analyzes the video captured by the door camera 11 and determines whether or not a dangerous event has occurred near the door. If a dangerous event is detected near the door (for example, when a passenger rushes to board), the control device 16 controls the door camera 11 that captured the video of the dangerous event to operating state S (high frame rate, high bitrate, low compression ratio) so that it can capture high-quality video of the dangerous event. Then, for example, after a predetermined time has elapsed, the control device 16 controls the door camera 11 to automatically return to its original operating state. This allows the high-quality video of the dangerous event to be displayed on the display device 15, and the high-quality video to be recorded on the recording device 17.

[0040] Figure 5 shows an example of the camera state transition when an emergency call button is pressed while the train is in motion. As explained with reference to Figure 2, regardless of the train's running state, the in-car camera 12 is recording low-quality video in operating state B. When the emergency call device 18 in any car is operated by a passenger or crew member, the control device 16 switches the in-car camera 12 in that car to operating state S (high frame rate, high bitrate, low compression ratio) in order to record high-quality video of the passenger compartment, as shown in Figure 5. Therefore, it becomes possible to understand the situation inside the car when the emergency call device 18 is operated, and to check, for example, whether there are any injured people or people who are shaken or confused due to a sudden stop such as an emergency stop. Then, for example, after a predetermined time has elapsed, the control device automatically returns the operating state of the in-car camera 12 to its original state. This allows the high-quality video of the emergency call to be displayed on the display device 15, and the high-quality video to be recorded on the recording device 17.

[0041] As described above, the monitoring system in this example has a forward-facing camera 13 mounted on the leading vehicle 10-1, which captures images in front of the vehicle, and the control device 16 is configured to change the frame rate, bit rate, and compression ratio of the forward-facing camera 13 according to the train's running state. More specifically, as shown in Figure 3, when the train starts moving, the control device performs a control (state B → state A) that increases the frame rate of the forward-facing camera 13 from "low" to "medium", increases the bit rate from "low" to "medium", and decreases the compression ratio from "high" to "low". Furthermore, if an obstacle is detected in the images captured by the forward-facing camera 13 as a result of analyzing the images captured by the forward-facing camera 13 while the train is running, the control device performs a control (state A → state S) that further increases the frame rate of the forward-facing camera 13 from "medium" to "high", increases the bit rate from "medium" to "high", and decreases the compression ratio from "medium" to "low". Thus, according to the monitoring system in this example, it is possible to automatically adjust the frame rate, bitrate, and compression ratio of the forward camera 13 according to the conditions while the train is running.

[0042] In the above explanation, the control device 16 instructs the forward camera 13 to increase the frame rate, increase the bit rate, and decrease the compression ratio when the train starts moving. However, it is also possible to instruct the forward camera 13 to increase at least one of the following: increase the frame rate, increase the bit rate, and decrease the compression ratio. This also makes it possible to suppress the storage capacity of the recording device 17 and reduce the network load.

[0043] Although embodiments of the present invention have been described above, these embodiments are merely illustrative and do not limit the technical scope of the present invention. The present invention can take many other embodiments, and various modifications such as omissions and substitutions can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention as described herein, and are included in the scope of the invention and its equivalents as described in the claims.

[0044] Furthermore, the present invention can be provided not only as the devices described above or as systems composed of such devices, but also as methods executed by these devices, programs for a processor to realize the functions of these devices, and storage media for storing such programs in a computer-readable manner. [Industrial applicability]

[0045] It can be used in surveillance systems equipped with multiple cameras mounted on trains. [Explanation of symbols]

[0046] 10-1~10-4: Vehicle, 11: Door camera, 12: Interior camera, 13: Front camera, 14: Relay device, 15: Display device, 16: Control device, 17: Recording device, 18: Emergency notification device

Claims

1. In a surveillance system with multiple cameras mounted on a train, One of the aforementioned multiple cameras includes a forward-facing camera mounted on the lead vehicle, which captures the area in front of that vehicle. A monitoring system characterized by comprising a control device that changes at least one of the frame rate, bitrate, and compression ratio of the forward camera according to the running state of the train.

2. In the monitoring system described in claim 1, The control device is characterized by transmitting a control signal to the forward camera instructing it to increase the frame rate, increase the bit rate, or decrease the compression ratio of the forward camera in response to the train starting to move.

3. In the monitoring system according to claim 1 or claim 2, The control device is further characterized in that it changes at least one of the frame rate, bitrate, and compression ratio of the forward camera according to the results of the analysis of the forward camera's captured video obtained while the train is in motion.

4. In the monitoring system described in claim 3, The control device is characterized by transmitting a control signal to the forward camera instructing it to increase the frame rate, increase the bitrate, or decrease the compression ratio of the forward camera in response to the detection of a predetermined obstacle from the image captured by the forward camera obtained while the train is in motion.

5. In the monitoring system described in claim 3, The control device is characterized by transmitting a control signal to the forward camera instructing it to increase the frame rate, increase the bitrate, or decrease the compression ratio of the forward camera in response to the detection of another train from the forward camera's video footage obtained while the train is in motion.

6. In the monitoring system described in claim 3, The monitoring system is characterized in that the control device transmits a control signal to the forward camera instructing it to increase the frame rate, increase the bitrate, or decrease the compression ratio of the forward camera in response to the detection of a moving object crossing the direction of travel of the train from the image captured by the forward camera obtained while the train is in motion.

7. In the monitoring system described in claim 3, The control device is characterized by transmitting a control signal to the forward camera instructing at least one of the following to increase the frame rate, increase the bitrate, or decrease the compression ratio, in response to the detection of an abnormality by comparing the image captured by the forward camera obtained while the train is running with a pre-prepared reference image.

Images