JP2024072513A - Signal, recognition device, signal system, and program - Google Patents

Abstract

[Problem] A system for recognizing the current state of a traffic light from a remote location at a lower cost than when using wireless communication devices. [Solution] An acquisition unit 111 acquires video captured at a specified frame rate from an image capture unit 17. A recognition unit 112 extracts flicker from the video acquired by the acquisition unit 111 and identifies its period. The recognition unit 112 uses the determined period of the flicker and a known frame rate to determine the blinking frequency of the light source causing the flicker in the video. If the determined frequency is one of the frequencies applied to the blinking of a signal light unit 21, the recognition unit 112 determines that the light source blinking at this frequency is a signal light unit 21, and recognizes the current state of the signal light unit 21. [Selected Figure] Figure 5

Description

The present invention relates to a technology for recognizing the type of traffic light indication.

When a signal light is recorded using a digital video camera or other device installed in the driver's seat of a railway vehicle, the lighting state and color of the light may be affected by weather, sunlight, etc. and may not be recognizable. Furthermore, in recorded videos, the light emitted by the signal light may be indistinguishable from the light emitted by light-emitting objects other than the signal light, such as the taillights of an automobile.

As a way to recognize the lighting status and color of signal lamps in the driver's cab of a railway vehicle, a method is being considered that uses wireless communication in parallel with the lighting of the signal lamps.

However, a communication system that uses wireless communication in addition to lighting requires dedicated antennas and communication circuits for each transmitting and receiving device, which increases the initial cost.

On the other hand, a method of transmitting information from a traffic signal to a railway vehicle or the like that uses the light emitted by the traffic signal lamp itself is also being considered. For example, Patent Document 1 discloses a vehicle communication system in which a fixedly-placed light-emitting device emits light with a predetermined signal superimposed thereon, and a light-receiving device on the vehicle receives the light and reads out the signal.

JP 2004-13401 A

The technology described in Patent Document 1 superimposes complex and voluminous information, such as information about traffic regulations, onto the light emitted by a traffic light. As a result, this technology must acquire this light in a state that allows it to be demodulated on the vehicle side, which requires a light-receiving element with a higher time resolution than a digital video camera, etc. In addition, this technology requires modulation and demodulation equipment for AM, FM, etc. on the transmitting and receiving devices.

One of the objectives of the present invention is to enable remote recognition of the signal state at a lower cost than using wireless communication devices.

In a first aspect, the present invention provides a traffic light that flashes at a frequency that causes flicker in video captured at a specified frame rate, the frequency being unique for each light aspect.

The first aspect of the traffic light makes it possible to have a device in a remote location recognize the type of light at a lower cost than if wireless communication equipment were used.

In the first embodiment of the traffic light, a second embodiment may be adopted in which the traffic light has two or more light sources that flash at a common frequency.

According to the second aspect of the traffic light, even if any of the two or more light sources cannot reach the vehicle, a device in a remote location can recognize the common signal type.

In the second embodiment of the traffic light, the two or more light sources may be configured to flash synchronously as a third embodiment.

The third aspect of the traffic light can prevent the blinking of two or more light sources from being mixed together and mistakenly perceived as a continuous light.

As a fourth aspect, the present invention provides a traffic light having two or more light sources that each flash at different frequencies, all of which are frequencies that cause flicker in a video captured at a predetermined frame rate, and the combination of the different frequencies is unique for each light aspect.

The fourth aspect of the traffic light can output more information about the current display type than when the multiple light sources of the traffic light flash at a common frequency.

In the fourth aspect of the traffic light, a fifth aspect may be adopted in which the two or more light sources flash at different frequencies for each color.

According to the fifth aspect of the traffic light, the different colors of two or more light sources can be represented by corresponding frequencies.

In a sixth aspect, the present invention provides a recognition device that recognizes the type of a traffic light indication based on the period of flicker caused by a light source contained in a video captured at a predetermined frame rate.

The recognition device of the sixth aspect allows the type of traffic light indication to be recognized remotely at a lower cost than when using wireless communication devices.

In the sixth aspect of the recognition device, if the video includes two or more light sources that each produce flicker with a different cycle, the seventh aspect may be configured to recognize the display type based on a combination of the cycles.

The seventh aspect of the recognition device allows more information about the current display type to be recognized than with multiple light sources that change at a common cycle.

In the recognition device of the sixth aspect, a configuration may be adopted as an eighth aspect in which it is determined whether the measured approach speed to the light source is within the range indicated by the recognized indication type.

The recognition device of the eighth aspect can determine whether a vehicle or the like is approaching a light source at a speed outside the allowable range indicated by the traffic light current.

In the recognition device of the eighth aspect, a configuration may be adopted as a ninth aspect in which a warning is issued when it is determined that the approach speed is not within the range.

The recognition device of the ninth aspect can warn when a vehicle or the like is approaching a light source at a speed outside the allowable range.

The present invention provides, as a tenth aspect, a traffic light system having a traffic light that flashes at a frequency that causes flicker in a video captured at a predetermined frame rate, the frequency being unique for each indication type, a camera that captures the traffic light at the predetermined frame rate, and a recognition device that acquires the video captured by the camera device and recognizes the indication type of the traffic light based on the period of the flicker contained in the video.

According to the signal system of the tenth aspect, the signal type can be recognized remotely at a lower cost than when using wireless communication devices.

In an eleventh aspect, the present invention provides a program for causing a computer to function as an acquisition means for acquiring a video captured at a predetermined frame rate, and a recognition means for recognizing the type of a traffic light indication based on the period of flicker caused by a light source contained in the video.

The program of the eleventh aspect allows the traffic light status to be recognized remotely at a lower cost than when using wireless communication devices.

FIG. 1 is a block diagram showing an example of the configuration of a signaling system 9 according to an embodiment of the present invention. FIG. 1 is a diagram showing an example of the configuration of a recognition device 1. FIG. 2 shows an example of the configuration of a traffic light 2. FIG. 2 is a circuit diagram showing an example of the configuration of a signal lamp unit 21. FIG. 2 is a diagram showing an example of the functional configuration of the recognition device 1. FIG. 13 is a diagram for explaining flicker. FIG. 4 is a flowchart showing an example of the operation flow of the recognition device 1. FIG. 11 is a flowchart showing an example of the operation flow of an instruction process.

<Embodiment>
<Signal system configuration>
Fig. 1 is a block diagram showing an example of the configuration of a signal system 9 according to an embodiment of the present invention. The signal system 9 shown in Fig. 1 includes a recognition device 1, a traffic light 2, a communication line 3, and a management device 4. In the signal system 9, each of these components may be provided in multiple units, or may include only one unit.

The signal system 9 may also use signals emitted from navigation satellites 5, as shown in FIG. 1. The signal system 9 uses at least four navigation satellites 5 to measure its position. The single navigation satellite 5 shown in FIG. 1 is drawn to represent the multiple navigation satellites 5 used by the signal system 9.

The management device 4 is a device that monitors the operation status of railway vehicles and controls and manages the signals 2 on the tracks in accordance with a timetable. The management device 4 is an information processing device, for example a computer. The management device 4 may be composed of a single information processing device, or may be composed of multiple information processing devices working together. The management device 4 controls the signals 2 via the communication line 3.

The communication line 3 is a line that connects the management device 4 and the signal device 2 via wired or wireless communication so that they can communicate with each other. It is preferable that the communication line 3 is a dedicated line in order to ensure the safety of railway operation management.

The signal 2 is communicatively connected to the management device 4 via the communication line 3, and issues instructions (also called indications) to railway vehicles under the control of the management device 4.

The recognition device 1 is a device that recognizes the indication type of the traffic light 2 by using a video captured remotely of the traffic light 2. The indication type is the type of indication of the traffic light 2. Examples of the indication types are high speed proceed, proceed, decelerate, caution, alert, stop, etc. The recognition device 1 is an information processing device, such as a smartphone, tablet PC, or slate PC. The recognition device 1 is mounted on, for example, a railway vehicle.

<Configuration of the recognition device>
2 is a diagram showing an example of the configuration of the recognition device 1. The recognition device 1 has a processor 11, a memory 12, a communication unit 13, an operation unit 14, a display unit 15, an alarm unit 16, an imaging unit 17, a positioning unit 18, and an inertial measurement unit 19. These are connected to each other via a bus so as to be able to communicate with each other.

The memory 12 is a storage means for storing the operating system, various computer programs (hereinafter simply referred to as programs), data, etc., that are loaded into the processor 11. The memory 12 has a RAM (Random Access Memory) and a ROM (Read Only Memory). The memory 12 may also have a solid state drive, a hard disk drive, etc.

The processor 11 controls the recognition device 1 by reading and executing a program from the memory 12. The processor 11 is, for example, a CPU (Central Processing Unit). The processor 11 may also be, for example, an FPGA (Field Programmable Gate Array), or may include an FPGA. The processor may also have an ASIC (Application Specific Integrated Circuit) or other programmable logic device, and may perform control by using these.

The communication unit 13 is a communication circuit that communicatively connects the recognition device 1 to an external device (also called an external device) via a wired or wireless connection. The external device to which the recognition device 1 connects is, for example, a control device that controls the operation of a railway vehicle.

The operation unit 14 includes operators such as operation buttons and a touch panel for issuing various instructions. The operation unit 14 receives an operation from a user and sends a signal corresponding to the operation to the processor 11. The operation unit 14 may include a keyboard and a mouse as operators.

The display unit 15 has a display screen such as a liquid crystal display, and displays images under the control of the processor 11. A transparent touch panel of the operation unit 14 may be placed on top of the display screen.

The alarm unit 16 is a device that notifies the user of the recognition device 1 when a dangerous or abnormal situation is detected by the recognition device 1. The alarm unit 16 is, for example, a speaker or a Patlite (registered trademark), and warns the user of the dangerous or abnormal situation by emitting sound or light.

The imaging unit 17 is a device that captures the scenery along the railway line, including the traffic signals 2, at a predetermined frame rate and generates a video. The imaging unit 17 includes an optical system, such as a lens, a mirror, a prism, and an imaging element, such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor. The imaging unit 17 is, for example, a digital video camera. The frame rate of the video captured by the imaging unit 17 is, for example, 60 fps (frames per second).

The positioning unit 18 is a receiver that constitutes a satellite positioning system such as the Global Navigation Satellite System (GNSS). The positioning unit 18 measures (i.e., positions) the position of the aircraft using signals emitted from the navigation satellites 5 shown in FIG. 1.

The inertial measurement unit 19, also known as an IMU (inertial measurement unit), is a device that measures angular velocity and acceleration in three-dimensional space. This inertial measurement unit 19 includes, for example, a three-axis gyroscope and a three-directional acceleration sensor. This inertial measurement unit 19 measures the angular velocity and acceleration of the recognition device 1, and determines the operating speed (hereinafter simply referred to as speed) of the railway vehicle or the like on which the recognition device 1 is mounted based on these measured values.

<Traffic Signal Configuration>
Fig. 3 is a diagram showing an example of the configuration of the traffic light 2. The traffic light 2 shown in Fig. 3 is a three-light traffic light.

This traffic light 2 has three signal lights 21G, 21Y, and 21R (hereinafter, when there is no need to distinguish between them, they will simply be referred to as "signal lights 21") that emit green, yellow, and red lights, respectively. The signal lights 21 may have lenses.

The number of signal lamps 21 that the traffic light 2 has is not limited to three as described above, but may be one, two, or four or more. In other words, the traffic light 2 is not limited to a three-lamp type, but may be, for example, a one-lamp type, two-lamp type, four-lamp type, five-lamp type, six-lamp type, etc.

In addition to the signal lamp 21, the traffic light 2 also has a housing 20 and a control panel 22. The housing 20 houses and fixes the signal lamp 21.

The control panel 22 includes a processor and a controller that controls the signal lights 21. This control panel 22 controls each of the signal lights 21 to turn them on or off.

The indication type of the traffic light 2 is represented by a combination of the on and off states of each of the signal lamps 21. For example, the traffic light 2 shown in Figure 3 indicates "proceed" when only the green signal lamp 21G of the three signal lamps 21 is turned on and the others are turned off. The traffic light 2 shown in Figure 3 also indicates "caution" and "stop" when only the signal lamp 21Y or only the signal lamp 21R is turned on, respectively.

The control panel 22 also causes one or more of the signal lamps 21 to be turned on to flash at a specific frequency according to the current state of the traffic light 2. This specific frequency is selected from a frequency band that causes flickering in the video captured by the image capture unit 17 of the recognition device 1. In other words, this traffic light 2 is an example of a traffic light that flashes at a specific frequency for each current state, at a frequency that causes flickering in the video captured at a predetermined frame rate.

The control panel 22 shown in FIG. 3 determines the frequency at which each signal lamp 21 flashes for each color (also called light color) of that signal lamp 21. The indication type of the traffic light 2 is determined by the combination of the on and off states of the signal lamps 21. Therefore, if the signal lamps 21 are made to flash at a frequency specific to each light color, the indication type expressed by the entire traffic light 2 is determined by the combination of these specific frequencies.

The signal lamps 21G, 21Y, and 21R each have a transformer 211G, 211Y, and 211R (hereinafter, when there is no need to distinguish between them, they will simply be referred to as "transformers 211") and a light-emitting unit 212G, 212Y, and 212R (hereinafter, when there is no need to distinguish between them, they will simply be referred to as "light-emitting units 212").

Figure 4 is a circuit diagram showing an example of the configuration of the signal lamp 21. The transformer 211 transforms the 100-V AC light color signal supplied from the control panel 22 and supplies the output signal to the light-emitting unit 212.

The light-emitting unit 212 is a device that flashes at a frequency specific to each display type under the control of the control panel 22. The light-emitting unit 212 has a rectifying smoothing circuit 2121, a non-contact relay 2122, a light source 2123, and a modulation unit 2124.

The rectifying and smoothing circuit 2121 converts the AC voltage that has passed through the transformer 211 into a DC voltage. The modulation unit 2124 supplies a signal (called a frequency signal) indicating the frequency at which the light source 2123 blinks to the non-contact relay 2122 in accordance with instructions from the control panel 22. The frequency indicated by this frequency signal is a frequency specific to each of the above-mentioned indication types.

The non-contact relay 2122 opens and closes the circuit in response to the frequency signal received from the modulation unit 2124. The light source 2123 has a light emitting element such as an LED (light emitting diode). The light source 2123 shown in FIG. 4 has multiple rows of light emitting elements connected in series, which are further connected in parallel. The number of rows of light emitting elements connected in parallel is, for example, six. The light source 2123 is turned on only when the circuit is closed by the non-contact relay 2122, and is turned off otherwise.

The three signal lamps 21 of this traffic light 2 each light up in a different color. When lit, these three signal lamps 21 blink their light sources 2123 at a frequency corresponding to each color under the control of the control panel 22.

Therefore, this traffic light 2 is an example of a traffic light that has two or more light sources that each flash at a different frequency, all of which are frequencies that cause flicker in a video captured at a predetermined frame rate, and the combination of these different frequencies is unique for each indication type. In addition, the three signal lamps 21 of this traffic light 2 are an example of two or more light sources that flash at different frequencies for each color.

<Functional Configuration of Recognition Device>
Fig. 5 is a diagram showing an example of the functional configuration of the recognition device 1. The processor 11 of the recognition device 1 reads and executes a program stored in the memory 12, thereby functioning as an acquisition unit 111, a recognition unit 112, a determination unit 113, and a warning unit 114. Note that the memory 12 is omitted in Fig. 6.

The acquisition unit 111 acquires video captured at a predetermined frame rate from the imaging unit 17. The recognition unit 112 extracts portions of flickering brightness from the video acquired by the acquisition unit 111, and identifies the period of the flicker.

Figure 6 is a diagram for explaining flicker. The signal light 21 blinks at a specified frequency in accordance with instructions from the control panel 22. The image capture unit 17 of the recognition device 1 captures the signal light 21 at a specified frame rate. At this time, the light of the signal light 21 appears to flicker in the video. This flickering of light is called flicker. The frequency of the flicker can be calculated as the greatest common denominator of the blinking frequency of the signal light 21 and the frame rate of the image capture by the image capture unit 17, when both are expressed as integers. The period of the flicker is the reciprocal of the calculated frequency.

As shown in FIG. 6(a), when the signal light 21 repeatedly flashes at 108 Hz, the flashing period is approximately 9.26 ms (milliseconds). When the image capture unit 17 captures video at a frame rate of 60 fps, the period between frames of the video is approximately 16.7 ms. At this time, the light intensity of the signal light 21 appears as flicker in the video and fluctuates at 12 Hz, which is the greatest common denominator of 108 Hz and 60 Hz. The period of this flicker is 83.3 ms.

When the blinking frequency of the signal light 21 changes, the flicker period also changes. For example, as shown in FIG. 6(b), when a signal light 21 blinking at 105 Hz is filmed at a frame rate of 60 fps, the light of the signal light 21 fluctuates at 15 Hz in the video. The flicker period is 66.7 ms. Also, as shown in FIG. 6(c), when a signal light 21 blinking at 102 Hz is filmed at a frame rate of 60 fps, the light of the signal light 21 fluctuates at 6 Hz in the video. The flicker period is 166.7 ms.

Therefore, the recognition unit 112 identifies the blinking parts in the acquired video, i.e., the flicker cycle. The recognition unit 112 then uses the determined flicker cycle and the known frame rate to determine the blinking frequency of the light source that is causing the flicker in the video.

Then, if the obtained frequency is one of the frequencies applied to the blinking of the signal light unit 21, the recognition unit 112 determines that the light source blinking at this frequency is a signal light unit 21, and recognizes the indication type of this signal light unit 21.

Therefore, the recognition device 1 having the processor 11 functioning as the recognition unit 112 is an example of a recognition device that recognizes the type of traffic light indication based on the period of flicker caused by a light source contained in a video captured at a predetermined frame rate.

The recognition unit 112 may also correct the determined flicker frequency using the speed of the recognition device 1 measured by the inertial measurement unit 19.

The determination unit 113 uses the speed of the recognition device 1 measured by the inertial measurement unit 19 and the position of the recognition device 1 measured by the positioning unit 18 to determine the speed at which the railway vehicle equipped with the recognition device 1 approaches the signal 2 (hereinafter also referred to as the approach speed). In addition, based on the indication type of the signal 2 recognized by the recognition unit 112, the determination unit 113 determines the range of approach speeds permitted for the railway vehicle, which is indicated by the indication type.

Then, the determination unit 113 determines whether the approach speed of the railway vehicle to the signal 2 (including the light source 2123) is within the range indicated by the recognized indication type. In other words, the recognition device 1 having the processor 11 functioning as this determination unit 113 is an example of a recognition device that determines whether the measured approach speed to the light source is within the range indicated by the recognized indication type.

The warning unit 114 controls the alarm unit 16 to issue a warning when the determination unit 113 determines that the approach speed of the railway vehicle to the signal 2 is not within the range indicated by the recognized indication type. In other words, the recognition device 1 having the processor 11 functioning as this warning unit 114 is an example of a recognition device that issues a warning when it determines that the measured approach speed to the light source is not within the range indicated by the recognized indication type.

<Operation of the recognition device>
<Overall operation>
7 is a flow diagram showing an example of the flow of the operation of the recognition device 1. The processor 11 of the recognition device 1 measures the approach speed of the railway vehicle equipped with the recognition device 1 to the signal 2 using the inertial measurement unit 19 and the positioning unit 18 (step S101). The processor 11 also acquires a video from the imaging unit 17 (step S102).

When the video is acquired, the processor 11 determines whether or not the video contains flicker (step S103). If the processor 11 determines that the video does not contain flicker (step S103; NO), the processor 11 returns the process to step S101.

On the other hand, if it is determined that the video has flicker (step S103; YES), the processor 11 identifies the period of the flicker (step S104).

Then, the processor 11 determines the blinking frequency of the light emitted by the signal lamp 21 in the traffic light 2 from the determined flicker period and the frame rate of the image capture unit 17 (step S105). At this time, the processor 11 may correct the blinking frequency using the above-mentioned approach speed.

When the frequency of the flashing light is identified, the processor 11 recognizes the signal type of the traffic light 2 based on this frequency (step S106), and performs instruction processing to issue an instruction to an external device via the display unit 15 or the communication unit 13 according to the recognized signal type (step S200).

When the instruction process is completed, the processor 11 determines whether or not a condition for terminating the recognition device 1 (also called a termination condition) has been satisfied (step S107). If the processor 11 determines that the termination condition has not been satisfied (step S107; NO), the processor 11 returns the process to step S101. If the processor 11 determines that the termination condition has been satisfied (step S107; YES), the processor 11 terminates the process.

<Operation of instruction processing>
Fig. 8 is a flow diagram showing an example of the operation flow of the instruction process. This instruction process is the process shown in step S200 in Fig. 7. As shown in Fig. 8, the processor 11 determines whether the recognized indication type is "proceed" (step S201).

When it is determined that the recognized indication type is "proceed" (step S201; YES), the processor 11 displays a proceeding indication on the display unit 15 indicating that the railway vehicle may proceed (step S202). The processor 11 then determines whether the approach speed of the railway vehicle equipped with the recognition device 1 to the signal 2 is 0 (step S203).

When it is determined that the approach speed is 0 (step S203; YES), the processor 11 instructs the control device of the railway vehicle to proceed via the communication unit 13 (step S204). On the other hand, when it is determined that the approach speed is not 0 (step S203; NO), the processor 11 ends this instruction process without performing step S204, and returns control to the caller.

If it is determined in step S201 that the recognized indication type is not "proceed" (step S201; NO), the processor 11 determines whether the recognized indication type is "caution" (step S205).

When it is determined that the recognized indication type is "Caution" (step S205; NO), the processor 11 displays a caution on the display unit 15, instructing the train to proceed with caution (step S206). The processor 11 then determines whether the approach speed of the train equipped with the recognition device 1 to the signal 2 exceeds a predetermined threshold (step S207).

When it is determined that the approach speed exceeds the threshold (step S207; YES), the processor 11 instructs the railcar control device to decelerate via the communication unit 13 (step S208). On the other hand, when it is determined that the approach speed does not exceed the threshold (step S207; NO), the processor 11 ends this instruction process without performing step S208, and returns control to the caller.

If it is determined in step S205 that the recognized indication type is not "Caution" (step S205; NO), the processor 11 determines whether the recognized indication type is "Stop" (step S209).

When it is determined that the recognized indication type is "stop" (step S209; NO), the processor 11 displays a stop indication on the display unit 15, indicating that the railway vehicle is to be stopped (step S210). The processor 11 then determines whether the approach speed of the railway vehicle equipped with the recognition device 1 to the signal 2 is 0 (step S211).

When it is determined that the approach speed is not 0 (step S211; NO), the processor 11 instructs the railcar control device to stop via the communication unit 13 (step S212). On the other hand, when it is determined that the approach speed is 0 (step S207; YES), the processor 11 ends this instruction process without performing step S212, and returns control to the caller.

By executing the process described above, the recognition device 1 recognizes the indication type of the traffic light 2 from a video captured of the traffic light 2. This recognition device 1 can recognize the indication type without using additional equipment such as a wireless communication circuit, so the initial cost is reduced compared to the case of introducing additional equipment.

The traffic light 2 described above can communicate the current state to the recognition device 1 simply by introducing a circuit that blinks a light source such as an LED at a specified frequency. Therefore, the traffic light 2 of the present invention can be manufactured from an existing traffic light.

The recognition device 1 described above recognizes the indication type of the traffic light 2 from video captured at a general frame rate by the image capture unit 17, which is a general-purpose digital video camera or the like. Therefore, this recognition device 1 is more cost-effective than devices that require modulation and demodulation of the light emitted by the traffic light.

The configuration, shape, size, and layout relationship described in the above embodiments are merely shown in a schematic manner to enable the present invention to be understood and implemented. Therefore, the present invention is not limited to the described embodiments, and can be modified in various forms without departing from the scope of the technical ideas set forth in the claims.

<Modification>
The above is a description of the embodiment, but the contents of this embodiment may be modified as follows. In addition, the following modifications may be combined.

＜1＞
In the above-described embodiment, the control panel 22 of the traffic signal 2 determines the frequency at which each signal lamp 21 flashes for each color of the signal lamp 21. However, the control panel 22 may flash each signal lamp 21 at a frequency that does not correspond to the color of the signal lamp 21.

For example, the control panel 22 may cause all of the signal lamps 21 that are turned on to flash at a unique frequency that corresponds to the indication type represented by the entire traffic signal 2. When two or more signal lamps 21 that are turned on simultaneously are each made to flash at a common frequency, if the common frequency corresponds to one indication type represented by the entire traffic signal 2, the indication type can be determined from the frequency regardless of the light color of each signal lamp 21.

＜2＞
In the above-described embodiment, the traffic light 2 is a three-light traffic light in which only one of the three signal lamps 21 is turned on. However, in the traffic light 2, the number of the signal lamps 21 that are turned on when one aspect is displayed is not limited to one. The traffic light 2 may simultaneously turn on two or more of the multiple signal lamps 21 when one aspect is displayed.

In addition, when one aspect is indicated by simultaneously lighting two or more signal lamps 21, the traffic light 2 may light these signal lamps 21 at a common frequency corresponding to the aspect type. In this case, the traffic light 2 is an example of a traffic light having two or more light sources that flash at a common frequency corresponding to the aspect type.

When two or more signal lights 21 are flashed simultaneously to indicate one indication type, it is desirable for the traffic light 2 to synchronize the flashing of those signal lights 21. This is because if the flashing signal lights 21 are close to each other, the light they emit may be photographed as mixed together and recognized as a single light flashing at different cycles as described above. When the flashing of two or more signal lights 21 is synchronized, the light source 2123 possessed by those signal lights 21 is an example of two or more light sources that flash in sync.

＜3＞
In the above-described embodiment, the recognition device 1 identifies the flicker period from a video captured of a three-light traffic light 2, identifies the blinking frequency of one of the signal lamps 21 that blinks in the traffic light 2, and recognizes the indication type. However, the recognition device 1 can also recognize the indication type of a traffic light 2 in which two or more signal lamps 21 blink simultaneously with different periods. In this case, the recognition device 1 extracts flicker occurring in the video by each of the signal lamps 21 that blink simultaneously with different periods, and identifies the periods of those flicker. The recognition device 1 identifies the blinking frequency of the corresponding signal lamp 21 from the periods of two or more flickers, and recognizes the indication type of the traffic light 2 from the combination of those frequencies. In this case, the recognition device 1 is an example of a recognition device that recognizes the indication type based on the combination of periods when the video includes two or more light sources that each generate flicker with different periods.

＜4＞
A signal system 9 having the recognition device 1 and traffic light 2 described in the above-mentioned embodiment and variant example is an example of a signal system having a traffic light that flashes at a frequency specific to each indication type, which frequency causes flicker in a video captured at a predetermined frame rate, a camera that captures the traffic light at the predetermined frame rate, and a recognition device that acquires the video captured by the camera device and recognizes the indication type of the traffic light based on the flicker period contained in the video.

＜5＞
In the above-described embodiment, the operations of the processor 11 may be performed not only by one processor 11 but also by multiple processors located at physically separate locations working together. The order of the operations of the processor 11 is not limited to the above-described order and may be changed as appropriate.

＜6＞
The program executed by the processor 11 of the recognition device 1 may be provided in a state stored in a computer-readable recording medium, such as a magnetic recording medium such as a magnetic tape or a magnetic disk, an optical recording medium such as an optical disk, a magneto-optical recording medium, a semiconductor memory, etc. The program may also be downloaded via a communication line such as the Internet. Note that various devices other than a CPU may be used as the control means exemplified by the processor 11 described above, and for example, a dedicated processor may be used.

The program executed by this processor 11 is an example of a program for causing a computer to function as an acquisition means for acquiring video captured at a predetermined frame rate, and as a recognition means for recognizing the type of traffic light indication based on the period of flicker caused by a light source contained in the video.

1...recognition device, 11...processor, 111...acquisition unit, 112...recognition unit, 113...determination unit, 114...warning unit, 12...memory, 13...communication unit, 14...operation unit, 15...display unit, 16...alarm unit, 17...photographing unit, 18...positioning unit, 19...inertial measurement unit, 2...traffic signal, 20...housing, 21 (21G, 21Y, 21R)...signal lamp, 211 (211G, 211Y, 211R)...transformer, 212 (212G, 212Y, 212R)...light emitting unit, 2121...rectification smoothing circuit, 2122...contactless relay, 2123...light source, 2124...modulation unit, 22...control panel, 3...communication line, 4...management device, 5...navigation satellite, 9...signal system.

Claims (11)

A traffic light that flashes at a frequency that causes flicker in video captured at a specified frame rate, and is unique to each light type. The traffic light of claim 1, having two or more light sources that flash at a common frequency. The traffic light according to claim 2, wherein the two or more light sources flash synchronously. A traffic light having two or more light sources that each flash at different frequencies, all of which cause flicker in video captured at a specified frame rate, and the combination of the different frequencies is unique for each light aspect. The traffic light according to claim 4, wherein the two or more light sources flash at different frequencies for each color. A recognition device that recognizes the type of traffic light indication based on the period of flicker caused by a light source contained in video captured at a specified frame rate. The recognition device according to claim 6, which recognizes the display type based on a combination of the periods when the video includes two or more light sources each producing a flicker with a different period. The recognition device according to claim 6, which determines whether the measured approach speed to the light source is within the range indicated by the recognized indication type. The recognition device according to claim 8 issues a warning when it is determined that the approach speed is not within the range. A traffic signal that flashes at a frequency that causes flicker in a video captured at a predetermined frame rate, the frequency being unique for each indication type;
an image capturing device that captures the traffic light at the predetermined frame rate;
a recognition device that acquires a video captured by the imaging device and recognizes the indication type of the traffic light based on the flicker period included in the video;
A signaling system having: Computer,
An acquisition means for acquiring a video shot at a predetermined frame rate;
A recognition means for recognizing a type of a traffic light based on a period of flicker caused by a light source included in the moving image;
A program to function as a

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