Onboard signal recognition system for railway and control method

Abstract

The purpose of the present invention is to provide an onboard signal recognition system for a railway, with which stable train operation can be realized by not recognizing that there are no signals only when a traffic light temporarily cannot be captured in the field of view of a camera, while reliably recognizing that there are no signals due to all lamps of the traffic light being off.　For this purpose, an onboard signal recognition system for a railway according to the present invention is characterized by comprising a determination information output device that outputs determination information indicating that a traffic light to be recognized is outside of the field of view of an imaging device, and a signal aspect recognition device that recognizes a signal aspect of a traffic light in front of a train using the determination information. For example, in recognition of the signal aspect of the traffic light, with reference to an acceleration sensor output value, the aspect recognition process is suspended while a predetermined threshold value is exceeded, and the aspect recognition process is restarted after the acceleration sensor output value returns to a specified value or lower.

Description

On-board signal recognition system and control method for railways

[0001] The present invention relates to a signal recognition system and a control method that is mounted on a train and recognizes the signal aspects of traffic signals.

[0002] There is a growing need for automated train operation in the railway industry. To realize an automated train operation system for railways, a function to recognize the signal aspects of traffic lights installed along the tracks is required. More specifically, it is necessary to recognize the signal aspects by comparing images of traffic lights acquired by cameras, etc., based on information such as the position of the train itself and the location and type of traffic lights.

[0003] A similar technology to this type of signal aspect recognition technology is described in, for example, Japanese Patent Laid-Open Publication No. 2011-201426 (Patent Document 1), which states, "The train is characterized by including an imaging device that captures images of the outside of the train, a GPS receiver that performs positioning using a satellite navigation system, a train position detection unit that obtains the train position based on the positioning results of the GPS receiver, a wayside equipment data storage unit that stores data on the positions and images of wayside equipment installed along the track, and a wayside equipment detection unit that detects the train's approach to the equipment position, captures images taken by the imaging device at different approach positions, detects the equipment images from the multiple images, and compares the detection results to confirm the operation of the wayside equipment" (paragraph 0008).

[0004] JP 2011-201426 A

[0005] Railway signals always display some kind of signal aspect, and when all lights on a signal are out, it is considered an abnormal condition called a no signal, and trains must stop immediately as they cannot run safely. In conventional signal systems, a no signal means that all lights are out and the information that the signal in question should show cannot be recognized. In systems that use camera images to recognize signal aspects, even if a signal that should exist cannot be found, it is natural to treat it as a no signal, since the information that the signal in question should show cannot be recognized, just as when all lights are out.

[0006] In automated train driving systems for railways, a camera is mounted near the driver's cab to capture the view ahead, but if the front of the train temporarily swings significantly to the left or right when passing through a switch, for example, the target signal may fall out of the camera's field of view. If the inability to find the target signal is treated as a no-signal in this case, the train may have to stop once every time it passes a switch, hindering stable train operation. On the other hand, if the system cannot correctly recognize a signal with all its lights off as a no-signal, it will not be able to operate as safely as before.

[0007] Patent Document 1 is for monitoring the operating status of railway line facilities, but does not consider the above-mentioned problem, i.e., how to reliably recognize a traffic light with all its lamps turned off as a no-signal, while realizing recognition processing in the case where the traffic light cannot be temporarily captured in the camera's field of view.

[0008] Therefore, the present invention aims to provide an on-board signal recognition system for railways that can ensure stable train operation by reliably recognizing no signal when all lamps on a traffic light are turned off, while not recognizing no signal only when the traffic light cannot be temporarily captured in the camera's field of view.

[0009] To solve the above problems, one representative example of the present invention is an on-board signal recognition system for railways, which is characterized by comprising a determination information output device that outputs determination information indicating that a traffic light to be recognized is out of the field of view of a photographing device, and a signal aspect recognition device that uses the determination information to recognize the signal aspect of a traffic light ahead of the train. For example, when recognizing the signal aspect of a traffic light, the system refers to the output value of an acceleration sensor, suspends the signal aspect recognition process while the output value exceeds a predetermined threshold, and resumes the signal aspect recognition process after the acceleration sensor output value returns to a specified value or below.

[0010] According to the present invention, when signal aspects are recognized using camera images, even if the front of the train swings significantly to the left or right when passing a switch, temporarily removing the target signal from the camera's field of view, it is possible to detect that the signal has temporarily left the camera's field of view by referring to the acceleration sensor output value, and the signal aspect recognition process is suspended while the acceleration sensor output value exceeds a predetermined threshold, and can be resumed when the acceleration sensor output value falls below the threshold. This makes it possible to achieve both no-signal recognition when all lamps are turned off, as in conventional signaling systems, and stable train operation by not recognizing a no-signal when the relevant signal is temporarily removed from the camera's field of view. Issues, configurations, and effects other than those described above will be made clear in the description of the embodiment below.

[0011] FIG. 1 is a diagram showing a first embodiment of the present invention; FIG. 2 is an example of the time course of acceleration sensor output when passing through a junction; FIG. 3 is a diagram showing a second embodiment of the present invention; FIG. 4 is a diagram showing a fourth embodiment of the present invention; and FIG. 5 is an example of the angle at which a traffic light is visible relative to the central axis of the photographing area of ​​the photographing device 1100 when passing through a junction.

[0012]

[0023] Hereinafter, embodiments will be described with reference to the drawings. [Embodiment 1] Fig. 1 is a diagram showing a first embodiment of the present invention. In this embodiment, an on-board signal recognition system 1000 according to the present invention includes an imaging device 1100, an on-board database device 1200, a train position detection device 1300, a determination information output device 1400, an acceleration sensor 1600, and a signal aspect recognition device 1500, and is mounted on a train.

[0013] The imaging device 1100 captures images of the road ahead using an optical camera mounted on the train and outputs the captured images. The on-board database device 1200 stores and outputs information (traffic light information) on the locations of traffic lights and the type of traffic light. The train position detection device 1300 detects and outputs the current position of the train (train position). The acceleration sensor 1600 outputs the acceleration of the imaging device 1100. As a specific example, it outputs acceleration in the lateral direction (horizontal to the ground) relative to the direction of train travel. The determination information output device 1400 uses the output value of the acceleration sensor 1600 to determine whether the front of the train is temporarily swinging to the left or right when passing a switch, for example, and outputs determination information if it determines that the traffic light to be recognized is outside the field of view of the imaging device 1100.

[0014] The signal aspect recognition device 1500 performs a process of recognizing the aspect of the signal ahead of the train using the captured image output by the imaging device 1100, the installation location and signal information of the signal to be recognized output by the on-board database device 1200, the train position output by the train position detection device 1300, and the judgment information output by the judgment information output device 1400, and outputs the results.

[0015] The signal aspect recognition device 1500 determines that there is no signal when all the lamps of the traffic light to be recognized are off or when a traffic light corresponding to the traffic light to be recognized cannot be recognized from the captured image, but does not determine that there is no signal even if the traffic light to be recognized cannot be recognized from the captured image while the judgment information is being output.

[0016] In this case, the signal aspect recognition device 1500 may retain the signal recognition result before the determination information was output and output the same signal recognition result while the determination information is being output, or may output a signal recognition result indicating that the signal recognition process has been suspended. If the signal aspect recognition process is retained, it can be easily resumed, and if it is suspended, it is possible to separately decide how to handle the process during that time. Which is more preferable depends on the specifications of another device (not mentioned in this specification) that receives the signal recognition result of the signal aspect recognition device 1500. As described above, in this embodiment, a control method including a process of outputting determination information from the determination information output device and a process of using the determination information to recognize the signal aspect of a signal ahead of the train is executed on board, thereby ensuring stable and safe train operation.

[0017] Figure 2 shows an example of the acceleration sensor output over time when the train passes through a turnout. In this figure, the horizontal axis represents the elapsed time, and the vertical axis represents the lateral acceleration of the image capture device 1100. The area above the vertical axis indicates, for example, acceleration to the left relative to the train's direction of travel, and the area below the vertical axis indicates acceleration to the right.

[0018] If the vehicle enters a switch at time T0 and then enters the left-hand track, the camera 1100 is temporarily accelerated to the left, then after time T1 it swings back and temporarily accelerates to the right, and at time T2 it passes the switch, with lateral acceleration reaching nearly zero. At this time, it can be determined from the acceleration that the camera 1100 is temporarily swung to the left in the T0-T1 section, and a threshold value Th21 at which the traffic light falls out of the field of view is determined in advance, and if the acceleration exceeds Th21, judgment information is output. Similarly, for the T1-T2 section, a threshold value Th22 is determined, and if the acceleration exceeds Th22, judgment information is output.

[0019] As shown in Figures 1 and 2, by performing recognition processing including judgment information when recognizing signal aspects, it is possible to provide an on-board signal recognition system for railways that can ensure stable train operation without signaling even when the signal cannot be recognized temporarily from the captured image.

[0020] [Embodiment 2] Figure 3 is a diagram showing a second embodiment of the present invention. In this embodiment, an illuminance sensor 3600 measures the brightness outside the train and outputs the measured brightness to a determination information output device 3400. The determination information output device 3400 detects the train's entry into or exit from a tunnel based on changes in illuminance (bright → dark, dark → bright), and outputs determination information for a predetermined period of time. The rest of the configuration is the same as in embodiment 1, so a description thereof will be omitted.

[0021] When an optical camera is used as the imaging device 1100 and automatic exposure control is performed, it takes time for the camera to track changes in brightness as the illuminance changes, resulting in a period of time when the image is temporarily overexposed or underexposed and the traffic light cannot be recognized from the captured image. Therefore, the signal aspect recognition device 1500 uses determination information to prevent the recognition of a no-signal state. For example, when the amount of change in illuminance exceeds a predetermined threshold, the determination information output device outputs determination information. This makes it possible to provide an on-board signal recognition system for railways that can ensure stable train operation without declaring a no-signal state even when the traffic light cannot be recognized temporarily after passing through a tunnel entrance or exit.

[0022] [Embodiment 3] Figure 4 is a diagram showing a third embodiment of the present invention. In this embodiment, the on-board database 4200 stores and outputs, in addition to the signal installation locations and signal information, exclusion section information indicating that in certain sections it is difficult for the imaging device 1100 to photograph the signals due to, for example, trackside structures or trees. The determination information output device 4400 uses the exclusion section information output by the on-board database device 4200 and the train position output by the train position detection device 1300, and outputs determination information when it detects that a train is currently located within the section indicated by the exclusion section information. The other configurations are the same as those of embodiments 1 and 2, so a description thereof will be omitted.

[0023] The signal aspect recognition device 1500 can provide an on-board signal recognition system for railways that can achieve stable train operation without signaling by performing signal recognition processing using the determination information, even when a traffic light is partially or entirely hidden by trackside structures or trees and cannot be photographed by the imaging device 1100. The excluded section information can also be used when the imaging device 1100 cannot photograph a traffic light due to the influence of curved sections or track gradients.

[0024] [Embodiment 4] Figure 5 is a diagram showing a fourth embodiment of the present invention. In this embodiment, the on-board database device 1200 outputs the location of traffic signals, and the train position detection device 1300 outputs the train position to the determination information output device 5400. The determination information output device 5400 estimates the direction of the train from the latest train position value and the value from one cycle ago, and outputs determination information if the traffic signal cannot be photographed by the photographing device 1100 based on the estimated values ​​of the location of the traffic signals, the current train position, and the train direction. The rest of the configuration is the same as in embodiments 1 to 3, so a description thereof will be omitted.

[0025] The signal aspect recognition device 1500 can provide an on-board signal recognition system for railways that can achieve stable train operation without signal non-operation by performing signal recognition processing using judgment information even when it is temporarily not possible to photograph traffic lights from the imaging device 1100, such as when passing through a switch or traveling on a curved section.

[0026] 6 shows an example of the angle at which a traffic light is visible relative to the central axis of the image capturing area of ​​the image capturing device 1100 when the train passes a switch. In this figure, the horizontal axis represents the elapsed time, and the vertical axis represents the angle at which the traffic light is visible relative to an axis extending vertically forward from the center of the image capturing area of ​​the image capturing device 1100. The upper side of the vertical axis represents, for example, the fact that the traffic light is visible to the left of the train's direction of travel and the estimated angle at which the traffic light is visible, and the lower side of the vertical axis represents the fact that the traffic light is visible to the right of the train's direction of travel and the estimated angle at which the traffic light is visible.

[0027] For example, if a vehicle enters a switch at time T0 and then enters the left-hand track, the camera 1100 will temporarily face left after T0, then swing back to face right after time T1, and when it passes the switch at time T2, it will face roughly toward the traffic light, and so on. The orientation of the camera 1100 changes over time. At this time, it can be determined from the estimated angle that the camera 1100 is temporarily swinging significantly to the left in the T0-T1 section. A threshold value Th61 at which the traffic light falls out of the field of view is determined in advance, and if the estimated angle exceeds Th61, determination information is output. Similarly, for the T1-T2 section, a threshold value Th62 is determined, and if the estimated angular acceleration exceeds Th62, determination information is output.

[0028] As shown in Figures 5 and 6, when recognizing signal aspects, by performing recognition processing including judgment information, it is possible to provide an on-board signal recognition device for railways that can ensure stable train operation without signaling even when the signal cannot be recognized from the captured image temporarily.

[0029] The present invention is not limited to the above-described embodiments and includes various modifications. The above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. In the above-described embodiments, the imaging device 1100 can also be applied to or used in combination with an optical camera in the visible light range, an optical camera in the non-visible light range (e.g., an infrared camera), etc.

[0030] The following are examples of aspects that may be included in the present invention, but the present invention is not limited to these. (Aspect 1) An on-board signal recognition system for railways, comprising: a determination information output device that outputs determination information indicating that a traffic light to be recognized is out of the field of view of a photographing device (1100); and a signal aspect recognition device (1500) that uses the determination information to recognize the signal aspect of a traffic light ahead of the train. (Aspect 2) The on-board signal recognition system for railways described in Aspect 1 is a system comprising: an acceleration sensor (1600) that measures the acceleration of the photographing device (1100); and the determination information output device (1400) outputs determination information when an output value of the acceleration sensor exceeds a predetermined threshold. (Aspect 3) The on-board signal recognition system for railways described in Aspect 1 or 2 is a system comprising: an illuminance sensor (3600) that measures the brightness outside the train; and the determination information output device (3400) outputs determination information when a change in the output value of the illuminance sensor exceeds a predetermined threshold. (Aspect 4) The railway on-board signal recognition system according to any one of Aspects 1 to 3, comprising: an on-board database device (4200) storing excluded section information indicating that a section in which a signal to be recognized is not within the field of view of the photographing device; and a train position detection device (1300), wherein the determination information output device (4400) outputs determination information using the excluded section information and the train position output by the train position detection device. (Aspect 5) The railway on-board signal recognition system according to any one of Aspects 1 to 4, comprising: an on-board database device (1200) and a train position detection device (1300), wherein the determination information output device (5400) outputs determination information using the signal installation positions output by the on-board database device and the train position output by the train position detection device. (Aspect 6) In the on-board signal recognition system for railways described in any one of Aspects 1 to 5, the signal aspect recognition device (1500) suspends signal recognition processing while the determination information is being output.(Aspect 7) The railway on-board signal recognition system according to any one of Aspects 1 to 5, wherein the signal aspect recognition device (1500) holds and continues to output the signal recognition result before the determination information is output while the determination information is being output. (Aspect 8) The railway on-board signal recognition system according to any one of Aspects 1 to 5, wherein the signal aspect recognition device (1500) suspends signal recognition processing while the determination information is being output, and resumes signal recognition processing after the determination information is no longer being output. (Aspect 9) The railway on-board signal recognition system according to any one of Aspects 1 to 5, wherein the signal aspect recognition device (1500) suspends signal recognition processing when the determination information is output, and resumes signal recognition processing after a predetermined suspension time has elapsed. (Aspect 10) A railway on-board signal recognition control method comprising the steps of: outputting, by a determination information output device, determination information indicating that a traffic light to be recognized is out of the field of view of a photographing device (1100); and using the determination information to perform signal aspect recognition of a traffic light ahead of the train by a signal aspect recognition device (1500). (Aspect 11) A railway on-board signal recognition control method according to Aspect 10, wherein the determination information is output when acceleration of the photographing device exceeds a predetermined threshold. (Aspect 12) A railway on-board signal recognition control method according to Aspect 10 or 11, wherein the determination information is output when a change in illuminance outside the train exceeds a predetermined threshold. (Aspect 13) A railway on-board signal recognition control method according to any one of Aspects 10 to 12, wherein the determination information is output based on excluded section information indicating that a section in which the traffic light to be recognized is out of the field of view of the photographing device, and the train position. (Aspect 14) The method for controlling on-board signal recognition for a railway vehicle according to any one of Aspects 10 to 13, wherein the determination information is output based on the installation position of a signal and the position of a train.(Aspect 15) The method for controlling on-board signal recognition for railways according to any one of Aspects 10 to 14, characterized in that signal recognition processing is suspended while the determination information is being output. (Aspect 16) The method for controlling on-board signal recognition for railways according to any one of Aspects 10 to 14, characterized in that signal recognition results before the determination information was output are held and output while the determination information is being output. (Aspect 17) The method for controlling on-board signal recognition for railways according to any one of Aspects 10 to 14, characterized in that signal recognition processing is suspended while the determination information is being output, and the signal recognition processing is resumed after the determination information is no longer being output. (Aspect 18) The method for controlling on-board signal recognition for railways according to any one of Aspects 10 to 14, characterized in that signal recognition processing is suspended when the determination information is output, and the signal recognition processing is resumed after a predetermined suspension time has elapsed.

[0031] 1000... On-board signal recognition system, 1100... Photography device, 1200, 4200... On-board database device, 1300... Train position detection device, 1400, 3400, 4400, 5400... Determination information output device, 1500... Signal aspect recognition device, 1600... Acceleration sensor, 3600... Illuminance sensor

Claims

1. a determination information output device that outputs determination information indicating that the traffic light to be recognized is temporarily out of the field of view of the photographing device (1100); A signal aspect recognition device (1500) that uses the determination information to recognize the signal aspect of a signal ahead of the train; An on-board signal recognition system for railways, comprising:

2. The on-board signal recognition system for railways according to claim 1 comprises: An acceleration sensor (1600) for measuring the acceleration of the photographing device (1100), An on-board signal recognition system for railways, characterized in that when the output value of the acceleration sensor exceeds a predetermined threshold value, the judgment information output device (1400) outputs judgment information.

3. (delete)

4. The on-board signal recognition system for railways according to claim 1 comprises: The system is provided with an on-board database device (4200) storing excluded section information indicating that the section is one in which a signal to be recognized is not within the field of view of the photographing device, and a train position detection device (1300), The judgment information output device (4400) is an on-board signal recognition system for railways, characterized in that it outputs judgment information using the excluded section information and the train position output by the train position detection device.

5. The on-board signal recognition system for railways according to claim 1 comprises: The system is equipped with an on-board database device (1200) and a train position detection device (1300), The judgment information output device (5400) is an on-board signal recognition system for railways, characterized in that it outputs judgment information using the signal installation location output by the on-board database device and the train position output by the train position detection device.

6. 6. The on-board signal recognition system for railways according to claim 1, 2, 4, or 5, The signal aspect recognition device (1500) suspends signal recognition processing while the judgment information is being output, in accordance with an on-board signal recognition system for railways.

7. 6. The on-board signal recognition system for railways according to claim 1, 2, 4, or 5, The signal aspect recognition device (1500) is an on-board signal recognition system for railways, characterized in that it retains and continues to output the signal recognition results before the determination information is output while the determination information is being output.

8. 6. The on-board signal recognition system for railways according to claim 1, 2, 4, or 5, The signal aspect recognition device (1500) suspends signal recognition processing while the judgment information is being output, and resumes signal recognition processing after the judgment information is no longer being output.

9. 6. The on-board signal recognition system for railways according to claim 1, 2, 4, or 5, The signal aspect recognition device (1500) is an on-board signal recognition system for railways, characterized in that it suspends signal recognition processing when the judgment information is output, and resumes signal recognition processing after a predetermined suspension time has elapsed.

10. a step of outputting, by a determination information output device, determination information indicating that the traffic light to be recognized is temporarily out of the field of view of the photographing device (1100); A step of using the determination information to recognize the signal aspect of a signal ahead of the train by a signal aspect recognition device (1500); A railway on-board signal recognition control method comprising:

11. The on-board signal recognition control method for railways according to claim 10, An on-board signal recognition control method for railways, characterized in that the judgment information is output when the acceleration of the photographing device exceeds a predetermined threshold.

12. (delete)

13. The on-board signal recognition control method for railways according to claim 10, An on-board signal recognition control method for railways, characterized in that the judgment information is output based on excluded section information indicating that the traffic light to be recognized is a section that is not within the field of view of the photographing device, and the train position.

14. The on-board signal recognition control method for railways according to claim 10, An on-board signal recognition control method for railways, characterized in that the judgment information is output based on the installation position of the signal and the train position.

15. a determination information output device that outputs determination information indicating that the traffic light to be recognized is temporarily out of the field of view of the photographing device (1100); a signal aspect recognition device (1500) that uses the determination information to recognize the signal aspect of a signal ahead of the train; The signal aspect recognition device does not recognize the signal as a no-signal while the judgment information is being output.

16. a step of outputting, by a determination information output device, determination information indicating that the traffic light to be recognized is temporarily out of the field of view of the photographing device (1100); and a step of using the determination information to recognize the signal aspect of a signal ahead of the train by a signal aspect recognition device (1500), The signal aspect recognition device does not recognize the signal as a no-signal while the judgment information is being output.