Vehicle detector, vehicle detection method, and program

Abstract

To provide a vehicle detector capable of suppressing erroneous recognition of two vehicles traveling in succession as a combination vehicle.SOLUTION: A vehicle detector comprises: an acquisition unit that acquires sensor information from a sensor installed at a first position in a lane direction; a first detection unit that detects a tail of a first vehicle at the first position based on the sensor information; a second detection unit that detects a head of a second vehicle at the first position subsequent to the detection of the tail of the first vehicle; and a determination unit that determines whether the first vehicle and the second vehicle are one connected-vehicle based on an elapsed time from detecting the tail of the first vehicle to detecting the head of the second vehicle.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a vehicle detector, a vehicle detection method, and a program. [Background technology]

[0002] On toll roads, different tolls may be charged depending on the type of vehicle. Also, when a vehicle is a combination vehicle consisting of a towing vehicle and a towed vehicle, a process may be performed to rank the vehicle up to a type that has a higher toll than the towing vehicle.

[0003] As a technology for detecting the presence or absence of a towed vehicle, for example, Patent Document 1 describes a towing determination system that focuses on the fact that the towing vehicle and towed vehicle each have a license plate, and when two license plates are detected on the rear side of a vehicle, determines that the license plates of the towing vehicle and towed vehicle have been detected, and determines that this vehicle is a combination vehicle. Patent Document 2 describes a vehicle detector that uses a reflective laser scanner to detect the coupling (tow bar) that connects the towing vehicle and towed vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-30574 A [Patent Document 2] JP 2019-133241 A Summary of the Invention [Problem to be solved by the invention]

[0005] Exhaust gas (water vapor) emitted from vehicles has the property of reflecting light. Therefore, when there is exhaust gas between two vehicles traveling consecutively, the vehicle detector receives the light reflected by the exhaust gas and erroneously detects the presence of a tow bar between the vehicles, which may result in the two vehicles traveling consecutively being mistaken for a combined vehicle (towing vehicle and towed vehicle).

[0006] The present disclosure has been made in consideration of such problems, and provides a vehicle detector, a vehicle detection method, and a program that can prevent two vehicles traveling consecutively from being mistakenly recognized as a combined vehicle consisting of a towing vehicle and a towed vehicle. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a vehicle detector includes an acquisition unit that acquires sensor information from a sensor installed at a first position in the lane direction, a first detection unit that detects the tail of a first vehicle at the first position based on the sensor information, a second detection unit that detects the head of a second vehicle at the first position following the detection of the tail of the first vehicle, and a determination unit that determines whether the first vehicle and the second vehicle are a single coupled vehicle based on the elapsed time between detecting the tail of the first vehicle and detecting the head of the second vehicle.

[0008] According to one aspect of the present disclosure, a vehicle detection method includes the steps of acquiring sensor information from a sensor installed at a first position in a lane direction; detecting a tail of a first vehicle at the first position based on the sensor information; following detection of the tail of the first vehicle, detecting a head of a second vehicle at the first position; and determining whether the first vehicle and the second vehicle are a connected vehicle based on the elapsed time between detecting the tail of the first vehicle and detecting the head of the second vehicle.

[0009] According to one aspect of the present disclosure, the program causes a computer of a vehicle detector to perform the following steps: acquiring sensor information from a sensor installed at a first position in the lane direction; detecting the tail of a first vehicle at the first position based on the sensor information; detecting the head of a second vehicle at the first position following the detection of the tail of the first vehicle; and determining whether the first vehicle and the second vehicle are a single connected vehicle based on the elapsed time between detecting the tail of the first vehicle and detecting the head of the second vehicle. Effect of the Invention

[0010] The vehicle detector, vehicle detection method, and program disclosed herein can prevent two vehicles traveling consecutively from being mistakenly recognized as a combined vehicle consisting of a towing vehicle and a towed vehicle. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing an overall configuration of a vehicle detection system according to a first embodiment of the present disclosure. [Diagram 2] 1 is a diagram illustrating a functional configuration of a vehicle detector according to a first embodiment of the present disclosure. [Diagram 3] 5 is a flowchart showing an example of processing of the vehicle detector according to the first embodiment of the present disclosure. [Figure 4] FIG. 2 is a diagram for explaining functions of a vehicle detector according to the first embodiment of the present disclosure. [Diagram 5] FIG. 11 is a diagram illustrating an overall configuration of a vehicle detection system according to a second embodiment of the present disclosure. [Figure 6] FIG. 11 is a diagram illustrating a functional configuration of a vehicle detector according to a second embodiment of the present disclosure. [Figure 7] 10 is a first flowchart showing an example of a process of a vehicle detector according to a second embodiment of the present disclosure. [Figure 8] 10 is a second flowchart showing an example of a process of the vehicle detector according to the second embodiment of the present disclosure. [Figure 9]FIG. 11 is a diagram for explaining functions of a vehicle detector according to a second embodiment of the present disclosure. [Figure 10] FIG. 11 is a diagram illustrating an overall configuration of a vehicle detection system according to a third embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram illustrating a functional configuration of a vehicle detector according to a third embodiment of the present disclosure. [Figure 12] FIG. 11 is a diagram for explaining functions of a vehicle detector according to a third embodiment of the present disclosure. [Figure 13] FIG. 2 is a diagram illustrating an example of a hardware configuration of a vehicle detector according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] <First embodiment> Hereinafter, a vehicle detection system 1 and a vehicle detector 10 according to a first embodiment of the present disclosure will be described with reference to FIGS.

[0013] (Overall composition) FIG. 1 is a diagram showing an overall configuration of a vehicle detection system according to a first embodiment of the present disclosure. As shown in FIG. 1, the vehicle detection system 1 includes a vehicle detector 10. The vehicle detector 10 is installed, for example, at a toll booth at the entrance or exit of a toll road. FIG. 1 shows an example in which the vehicle detector 10 is installed at an exit toll booth. At the exit toll booth, a lane L is provided that connects the toll road and a general road. In the following, the direction in which the lane L extends is referred to as the "lane direction (X direction)" and the width direction of the lane L is referred to as the "lane width direction (Y direction)". In addition, the toll road side of the lane L is referred to as the "upstream side (-X side)" and the general road side is referred to as the "downstream side (+X side)".

[0014] As shown in FIG. 1, the vehicle detector 10 has a sensor 11 (hereinafter also referred to as a reflective sensor) installed at a first position X1 in the lane direction on the roadside (on island I) of lane L of the toll gate. The vehicle detector 10 acquires sensor information from the reflective sensor 11 to detect whether or not vehicle A is present at the first position X1. The vehicle detector 10 also outputs a vehicle detection signal (a signal indicating "vehicle detection" or "vehicle non-detection") indicating whether or not vehicle A is present to another device (not shown). The other device may be, for example, a vehicle type discrimination device that discriminates the vehicle type of vehicle A, an electronic toll collection system (ETC (registered trademark), also called "automatic toll collection system") that collects tolls by wirelessly communicating with an on-board device mounted on vehicle A, or the like. Note that, in this embodiment, an aspect in which the sensor 11 is a reflective sensor will be described, but the present invention is not limited to this. The sensor 11 according to other embodiments may be another type of sensor, such as a transmission sensor.

[0015] (Functional configuration) FIG. 2 is a diagram illustrating a functional configuration of the vehicle detector according to the first embodiment of the present disclosure. As shown in FIGS. 1 and 2, the vehicle detector 10 includes a reflective sensor 11, a CPU 12, and a storage medium 13.

[0016] The reflective sensor 11 is, for example, a laser scanner. The reflective sensor 11 projects a laser beam from one light projecting / receiving unit 110 while changing the scanning angle, scans a predetermined target range R1 (FIG. 1) set at a first position X1 on the lane L, and detects the reflected position of the laser beam in the target range R1 based on the reflected light of the laser beam. The target range R1 of the reflective sensor 11 is a plane (YZ plane) perpendicular to the lane L at the first position X1, as shown in FIG. 1. The reflective sensor 11 detects the reflected position (YZ coordinate) of the laser beam in the lane width direction (Y direction) and height direction (Z direction) based on the scanning angle at which the laser beam is projected and the distance from the light projecting / receiving unit 110 to the object that reflected the laser beam, which is calculated based on the reflected light of the laser beam. The reflective sensor 11 outputs the distance and YZ coordinate of the reflected position for each scanning angle detected in one scan to the CPU 12 as sensor information.

[0017] In another embodiment, the reflective sensor 11 may be a single-optical axis multi-stage laser sensor. In this case, the reflective sensor 11 has a plurality of light projecting and receiving units 110 arranged in the height direction (Z direction in FIG. 1). Each light projecting and receiving unit 110 projects a laser beam in the horizontal direction (Y direction in FIG. 1) and detects the reflection position of the laser beam within the target range R1. In this case, the reflective sensor 11 outputs the distance and YZ coordinates of the reflection position detected by each of the light projecting and receiving units 110 from the top to the bottom as sensor information to the CPU 12.

[0018] The CPU 12 is a processor that controls the overall operation of the vehicle detector 10. The CPU 12 performs the functions of an acquisition unit 120, a first detection unit 121, a second detection unit 122, and a determination unit 123 by operating according to a predetermined program.

[0019] The acquisition unit 120 acquires sensor information from the reflective sensor 11 .

[0020] The first detection unit 121 detects the head and tail of the first vehicle A1 at the first position X1 based on the sensor information. The first vehicle A1 indicates the preceding vehicle traveling downstream in the lane direction (+X side in FIG. 1) among two vehicles traveling consecutively. The first vehicle A1 also indicates the towing vehicle among the combination vehicles consisting of a towing vehicle and a towed vehicle.

[0021] After detecting the tail of the first vehicle A1, the second detection unit 122 detects the head of the second vehicle A2 at the first position X1. The second vehicle A2 is the following vehicle that is traveling upstream in the lane direction (the -X side in FIG. 1) of two vehicles traveling consecutively. The second vehicle A2 is the towed vehicle of a combination of vehicles consisting of a towing vehicle and a towed vehicle.

[0022] The determination unit 123 determines whether the first vehicle A1 and the second vehicle A2 are a single coupled vehicle based on the elapsed time from when the tail of the first vehicle A1 is detected to when the head of the second vehicle A2 is detected.

[0023] The storage medium 13 stores information acquired and generated by each section of the vehicle detector 10, information referenced in the processing of each section, and the like.

[0024] (Processing flow) FIG. 3 is a flowchart illustrating an example of processing of the vehicle detector according to the first embodiment of the present disclosure. Hereinafter, the flow of processing by the vehicle detector 10 will be described with reference to FIG.

[0025] First, the determination unit 123 of the vehicle detector 10 sets the vehicle detection signal to a "vehicle not detected" state as an initial value (step S100).

[0026] The reflective sensor 11 constantly projects and receives laser light at the first position X1, and outputs sensor information including the distance and YZ coordinates of the reflected position of the laser light. The acquisition unit 120 acquires the sensor information output from the reflective sensor 11 (step S101).

[0027] Next, the first detection unit 121 determines whether or not the first vehicle A1 is present at the first position X1 based on the acquired sensor information. The first detection unit 121 according to this embodiment specifies a detection range in the height direction (Z direction in FIG. 1) of an object (detection target object) present at the first position X1 on the lane L from the sensor information, and determines whether or not this detection range has a size equal to or larger than a predetermined first threshold (step S102).

[0028] For example, the scan result by the reflective sensor 11 when the vehicle A is not present at the first position X1, i.e., the reflection position of the laser light on the road surface of the lane L (YZ coordinates, distance from the light projector / receiver 110) is measured in advance and stored as reference information in the storage medium 13. When the reflection position included in the sensor information is higher than the position of the road surface of the lane L included in the reference information, the first detection unit 121 determines that a detection target is present at the reflection position. Note that, taking into account the measurement error of the reflective sensor 11, the first detection unit 121 may determine that an object is present at the reflection position when the position in the height direction of the reflection position is higher than the position of the road surface by a measurement error range or more. Furthermore, if the detection range (size) of the detected object in the height direction (Z direction in FIG. 1) is equal to or larger than a predetermined first threshold (step S102: YES), the first detection unit 121 determines that the first vehicle A1 is present at the first position X1 (the head of the first vehicle A1 has been detected), and sets the vehicle detection signal to "vehicle detection" (step S103). This vehicle detection signal is notified to other devices such as a vehicle type discrimination device. This allows the vehicle type discrimination device, etc. to know that the first vehicle A1 has entered the lane L.

[0029] On the other hand, if no object is detected, or if the height direction size of the detected object is less than the first threshold (step S102: NO), the first detection unit 121 returns to step S100 and maintains the vehicle non-detection state.

[0030] If the head of the first vehicle A1 is detected (step S102: YES), the acquisition unit 120 further acquires the next sensor information (step S104). The first detection unit 121 determines whether the tail of the first vehicle A1 is detected at the first position X1 based on the next sensor information (step S105).

[0031] Specifically, the first detection unit 121 identifies a detection range in the height direction (Z direction in Figure 1) of vehicle A from the sensor information, and if this detection range is equal to or greater than a predetermined second threshold (step S105: NO), it determines that the first vehicle A1 is present at the first position X1 (the first vehicle A1 detected in step S103 is traveling at the first position X1), and returns to step S103.

[0032] On the other hand, when the detection range in the height direction of the first vehicle A1 is less than the second threshold value (step S105: YES), the first detection unit 121 determines that the tail of the first vehicle A1 has been detected.

[0033] Next, the first detection unit 121 judges whether only the road surface of the lane L has been detected based on the sensor information of the reflection sensor 11 (step S106). If the sensor information includes only information indicating the reflection position from the road surface (distance, YZ coordinates), the first detection unit 121 judges that only the road surface has been detected (step S106: YES). In this case, the determination unit 123 judges that the first vehicle A1 is an unconnected vehicle (step S107) and executes processing for the case where there is no towed vehicle (step S108). The processing for the case where there is no towed vehicle is similar to the processing in a conventional vehicle detector. For example, in step S108, the determination unit 123 sets the vehicle detection signal to "vehicle not detected" and notifies other devices such as a vehicle type discrimination device. This allows the vehicle type discrimination device and the like to know that the first vehicle A1 has passed the first position X1. After completing the process of step S108, the vehicle detector 10 executes the steps of FIG. 3 again for the second vehicle A2, which is the following vehicle.

[0034] On the other hand, if a tow bar is connected to the tail of the first vehicle A1, or if exhaust gas is being discharged from the first vehicle A1, the sensor information includes information that does not match the reflection position on the road surface (for example, the height position is a position that is a measurement error or more from the road surface). In this case, the first detection unit 121 determines that an object other than the road surface has been detected (step S106: NO).

[0035] Furthermore, if something other than the road surface is detected following the detection of the tail of the first vehicle A1 (step S106: NO), the acquisition unit 120 further acquires the next sensor information (step S109).Then, the second detection unit 122 determines whether the head of the second vehicle A2 (the following vehicle or the towed vehicle) has been detected at the first position X1 based on the next sensor information (step S110).

[0036] Here, the second detection unit 122 performs the same process as in step S102. If the detection range in the height direction of an object other than the road surface, which is identified from the sensor information, is less than a predetermined first threshold (step S110: NO), the second detection unit 122 returns to step S106.

[0037] On the other hand, if the detection range in the height direction is equal to or greater than the first threshold value (step S110: YES), the second detection unit 122 determines that it has detected the head of the second vehicle A2 at the first position X1.

[0038] When the second detection unit 122 detects the head of the second vehicle A2, the determination unit 123 determines whether the first vehicle A1 and the second vehicle A2 are combined vehicles or each is a single uncombined vehicle.

[0039] FIG. 4 is a diagram for explaining the function of the vehicle detector according to the first embodiment of the present disclosure. As shown in Fig. 4, when the first vehicle A1 and the second vehicle A2 are combined vehicles connected by a tow bar B, they travel without much distance between them, so that the second vehicle A2 reaches the first position in a short time after the first vehicle A1 passes the first position X1. On the other hand, when the first vehicle A1 and the second vehicle A2 are not combined and each travels independently, the first vehicle A1 and the second vehicle A2 travel with a certain distance between them for safety, so that the time from when the first vehicle A1 passes the first position X1 until when the second vehicle A2 reaches the first position X1 is longer than when they are combined vehicles. Therefore, it is assumed that when the detection time difference between the first vehicle A1 and the second vehicle A2 is short, it is highly likely that these vehicles are combined vehicles, and when it is long, it is highly likely that these vehicles are uncombined vehicles. Based on this assumption, the judgment unit 123 judges whether the elapsed time t1 from the time ts1 when the tail of the first vehicle A1 is detected at the first position X1 to the time ts2 when the head of the second vehicle A2 is detected at the first position X1 is less than or equal to a predetermined time tn (step S111).

[0040] The determination unit 123 sets the predetermined time tn according to the travel speed of the vehicle on the lane L and the towing length (the distance between the towing vehicle and the towed vehicle). The travel speed may be the speed limit set for the lane L, or may be the average speed measured on the lane L. For example, assume that the average speed is 30 km per hour (approximately 8 m per second). If the preset towing length is 500 mm, the head of the towed vehicle will be detected within approximately 60 msec after the tail of the towing vehicle is detected. In this case, the predetermined time tn is set to "60 msec."

[0041] If the elapsed time t1 is equal to or shorter than the predetermined time tn (step S111: YES), the determination unit 123 determines that the first vehicle A1 and the second vehicle A2 are combined vehicles (step S114) and executes the process for the case where a towed vehicle is present (step S115). The process for the case where a towed vehicle is present is similar to the process in a conventional vehicle detector. For example, in step S115, the determination unit 123 further repeatedly executes the processes in steps S103 to S108 until the first vehicle A1 (towing vehicle) and the second vehicle A2 (towed vehicle) are no longer detected. Furthermore, the vehicle detector 10 notifies the vehicle type discrimination device or the like of a vehicle detection signal indicating that one combined vehicle is continuing to travel until the second vehicle A2 (towed vehicle) passes the first position X1.

[0042] On the other hand, when the elapsed time t1 is greater than the predetermined time (step S111: NO), the determination unit 123 determines that the first vehicle A1 and the second vehicle A2 are uncoupled vehicles or are unknown (step S112). The vehicle detector 10 executes processing for the case where there is no towed vehicle or processing for the case where the towed vehicle is unknown (step S113). For example, in step S113, the determination unit 123 sets the vehicle detection signal to "vehicle not detected" and notifies other devices such as a vehicle type discrimination device. In addition, in step S113, the determination unit 123 may notify the vehicle type discrimination device, a monitoring panel at the toll gate office, and the like of a signal indicating that a vehicle that is unknown whether it is a coupled vehicle has been detected, together with the vehicle detection signal indicating "vehicle not detected". For example, when the vehicle type discrimination device is notified that a vehicle that is unknown whether it is a coupled vehicle has been detected, it transmits an image of the vehicle A captured by a camera to the monitoring panel at the toll gate office (not shown) with an instruction to confirm the presence or absence of a towed vehicle. This allows the toll booth attendant to check via the monitoring panel whether or not there is a vehicle being towed by vehicle A, and to take appropriate action to correct the type of vehicle A, the toll fee, etc.

[0043] (Action and effect) As described above, the vehicle detector 10 of this embodiment comprises an acquisition unit 120 that acquires sensor information from the reflective sensor 11, a first detection unit 121 that detects the tail of the first vehicle A1 at the first position X1 based on the sensor information, a second detection unit 122 that detects the head of the second vehicle A2 at the first position X1 following the detection of the tail of the first vehicle A1, and a determination unit 123 that determines whether the first vehicle A1 and the second vehicle A2 are a single coupled vehicle based on the elapsed time from detecting the tail of the first vehicle A1 to detecting the head of the second vehicle A2.

[0044] Conventional vehicle detectors may erroneously recognize the first and second vehicles as one coupled vehicle when exhaust gas is present between the first and second vehicles. However, the vehicle detector 10 according to the present embodiment has the above-mentioned features, and therefore, even if an object is detected between the first and second vehicles A1 and A2, it can appropriately determine whether the vehicles are coupled from the detection time difference between the first and second vehicles A1 and A2. As a result, the vehicle detector 10 can suppress erroneous recognition of two vehicles traveling consecutively as coupled vehicles.

[0045] In addition, the determination unit 123 determines that the first vehicle A1 and the second vehicle A2 are a single coupled vehicle if the elapsed time between detecting the tail of the first vehicle A1 and detecting the head of the second vehicle A2 is less than a predetermined time.

[0046] If the first vehicle A1 and the second vehicle A2 are single vehicles that are not coupled, they should travel with a safe distance between them. In this case, it is assumed that the time from detecting the tail of the first vehicle A1 to detecting the head of the second vehicle A2 will be longer than in the case of coupled vehicles. Based on this assumption, when the first vehicle A1 and the second vehicle A2 are detected consecutively at an interval of a predetermined time or less, the vehicle detector 10 can appropriately determine that there is a higher possibility that these vehicles are coupled vehicles than that they are uncoupled vehicles. This allows the vehicle detector 10 to reduce the possibility of misidentifying uncoupled vehicles and coupled vehicles.

[0047] <Second embodiment> Next, a vehicle detection system 1 and a vehicle detector 10 according to a second embodiment of the present disclosure will be described with reference to Fig. 5 to Fig. 9. Components common to the first embodiment will be denoted by the same reference numerals and detailed description will be omitted.

[0048] (Overall composition) FIG. 5 is a diagram showing an overall configuration of a vehicle detection system according to the second embodiment of the present disclosure. As shown in FIG. 5, in the vehicle detection system 1 according to this embodiment, the vehicle detector 10 includes two reflective sensors: a first reflective sensor 11 (first sensor) and a second reflective sensor 14 (second sensor).

[0049] The first reflective sensor 11 is the same as the reflective sensor 11 according to the first embodiment. The first reflective sensor 11 is installed at a first position X1 in the lane direction (X direction).

[0050] The second reflective sensor 14 uses the same equipment (for example, a laser scanner) as the first reflective sensor 11. The second reflective sensor 14 is installed at a second position X2 downstream (+X side) in the lane direction from the first position X1. Also, the distance d1 in the lane direction from the first position X1 to the second position X2 is measured in advance and stored in the storage medium 13 of the vehicle detector 10. The second reflective sensor 14 projects laser light from the light projecting / receiving unit 140, scans a predetermined second target range R2 set at the second position X2 on the lane L, and detects the reflection position of the laser light in the second target range R2 based on the reflected light of the laser light. The second reflective sensor 14 outputs the distance and YZ coordinates of the reflection position for each scanning angle detected in one scan to the CPU 12 as sensor information.

[0051] (Functional configuration) FIG. 6 is a diagram illustrating a functional configuration of a vehicle detector according to the second embodiment of the present disclosure. As shown in FIG. 6, the CPU 12 of the vehicle detector 10 further includes a vehicle speed calculation unit 124.

[0052] The first detection unit 121 according to this embodiment detects the head and tail of the first vehicle A1 at the first position X1 based on the sensor information of the first reflective sensor 11. The first detection unit 121 further detects the head of the first vehicle A1 at the second position X2 based on the sensor information of the second reflective sensor 14.

[0053] The vehicle speed calculation unit 124 calculates the vehicle speed of the first vehicle A1 or the second vehicle based on the sensor information of the first reflective sensor 11 and the second reflective sensor 14.

[0054] In addition, the determination unit 123 in this embodiment determines that the first vehicle A1 and the second vehicle A2 are combined vehicles when the elapsed time from detecting the tail of the first vehicle A1 to detecting the head of the second vehicle A2, and the distance from the tail of the first vehicle A1 to the head of the second vehicle A2 calculated from the vehicle speed of the first vehicle A1 or the second vehicle, is less than a predetermined distance.

[0055] (Processing flow) FIG. 7 is a first flowchart illustrating an example of processing of the vehicle detector according to the second embodiment of the present disclosure. FIG. 8 is a second flowchart illustrating an example of the process of the vehicle detector according to the second embodiment of the present disclosure. FIG. 9 is a diagram for explaining functions of the vehicle detector according to the second embodiment of the present disclosure. Hereinafter, the flow of processing by the vehicle detector 10 will be described with reference to Fig. 7 to Fig. 9. The vehicle detector 10 according to this embodiment executes the processing of steps S211 to S213 instead of step S111 in the first embodiment (Fig. 3). Note that the contents of the processing of steps S200 to S210 in Fig. 7 are similar to steps S100 to S110 in the first embodiment, respectively, and therefore description thereof will be omitted.

[0056] As shown in FIG. 9, it is assumed that the first detection unit 121 detects the head of the first vehicle A1 at the first position X1 based on the sensor information of the first reflective sensor 11 at time ts1 (step S202 in FIG. 7: YES).

[0057] After that, the vehicle detector 10 according to the present embodiment further executes a process of detecting the head of the first vehicle A1 at the second position X2 in parallel with the process of FIG. 7. Specifically, as shown in FIG. 8, the acquisition unit 120 acquires sensor information from the second reflective sensor 14 (step S220). Then, the first detection unit 121 determines whether or not the first vehicle A1 is present at the second position X2 based on the acquired sensor information. This process is the same as step S202 in FIG. 7. That is, the first detection unit 121 determines whether or not an object whose size in the height direction (Z direction in FIG. 5) is equal to or larger than a first threshold value is present at the second position X2 of the lane L based on the sensor information (step S221).

[0058] If no object is detected at the second position X2, or if the size in the height direction of the detected object to be detected is less than the first threshold (step S221: NO), the first detection unit 121 returns to step S220.

[0059] 9, the first detection unit 121 detects an object having a size equal to or larger than the first threshold from the sensor information of the second reflective sensor 14 acquired at time ts2 (step S221: YES). In this case, the first detection unit 121 determines that it has detected the head of the first vehicle A1 at the second position X2 at time ts2 (step S223).

[0060] Also, the vehicle detector 10 continues the process of Fig. 7 in parallel with the process of Fig. 8. For example, as shown in Fig. 9, it is assumed that the first detection unit 121 detects the tail of the first vehicle A1 at the first position X1 at time ts3 (step S205: YES). Subsequently, it is assumed that the second detection unit 122 detects the head of the second vehicle A2 at the first position X1 at time ts4 without detecting the road surface after detecting the tail of the first vehicle A1 (step S210: YES). In this case, the vehicle speed calculation unit 124 calculates the vehicle speed of the first vehicle A1 (step S211). The vehicle speed calculation unit 124 calculates the vehicle speed v1 of the first vehicle A1 using the distance d1 (Figures 5 and 9) from the first position X1 to the second position X2 and the time t1 from the time ts1 when the head of the first vehicle A1 is detected at the first position X1 to the time ts2 when it is detected at the second position X2, according to the following equation (1).

[0061] v1 = d1 / t1 (1)

[0062] In step S211, the vehicle speed calculation unit 124 may calculate the vehicle speed v1 of the second vehicle A2 based on the above formula (1). In this case, the time t1 in formula (1) is the time from the time when the head of the second vehicle A2 is detected at the first position X1 to the time when it is detected at the second position X2.

[0063] Next, the determination unit 123 obtains the inter-vehicle distance between the first vehicle A1 and the second vehicle A2 based on the vehicle speed v1 of the first vehicle A1, and determines whether the inter-vehicle distance is equal to or less than a predetermined distance dn (for example, 500 mm) (step S213). The predetermined distance dn may be set, for example, in consideration of the minimum inter-vehicle distance when the lane L is congested. Specifically, first, the determination unit 123 calculates the inter-vehicle distance d2 from the tail of the first vehicle A1 to the head of the second vehicle A2 by the following formula using the vehicle speed v1 of the first vehicle A1 and the time t2 from the time ts3 when the tail of the first vehicle A1 is detected at the first position X1 to the time when the head of the second vehicle A2 is detected.

[0064] d2 = v1 × t2 (2)

[0065] When the vehicle speed v1 of the second vehicle A2 is calculated in step S211, the determination unit 123 determines the inter-vehicle distance based on the vehicle speed of the second vehicle A2.

[0066] If the vehicle distance d2 is equal to or less than the predetermined distance dn (step S213: YES), the determination unit 123 determines that the first vehicle A1 and the second vehicle A2 are articulated vehicles (step S216) and executes the process for when a towed vehicle is present (step S217). This process is the same as step S115 in the first embodiment (FIG. 3).

[0067] On the other hand, if the vehicle distance d2 is greater than the predetermined distance dn (step S213: NO), the determination unit 123 determines that the first vehicle A1 and the second vehicle A2 are uncoupled vehicles or are unknown (step S214). The vehicle detector 10 executes processing for the case where there is no towed vehicle or processing for the case where the towed vehicle is unknown (step S215). This processing is the same as step S113 in the first embodiment (FIG. 3).

[0068] (Action and effect) As described above, the vehicle detector 10 of this embodiment further includes a vehicle speed calculation unit 124 that calculates the vehicle speed v1 of the first vehicle A1, and the determination unit 123 determines that the first vehicle A1 and the second vehicle A2 are combined vehicles when the distance (inter-vehicle distance) from the tail of the first vehicle A1 to the front of the second vehicle A2 based on the vehicle speed v1 of the first vehicle A1 is less than a predetermined distance.

[0069] In this way, the vehicle detector 10 can calculate the inter-vehicle distance between the first vehicle A1 and the second vehicle A2 from the speed of the first vehicle A1 and the detection time difference between the first vehicle A1 and the second vehicle A2, and can more accurately determine whether these vehicles are combined vehicles. Even if the flow of traffic in the lane L slows down due to congestion, for example, the inter-vehicle distance should be maintained to some extent. Therefore, the vehicle detector 10 can suppress a decrease in the accuracy of the determination due to the influence of the fluctuation in the detection time difference between the first vehicle A1 and the second vehicle A2 according to the flow speed of the lane L by determining whether the vehicles are combined vehicles based on the inter-vehicle distance.

[0070] 7 to 9 show an example in which the first detection unit 121 detects the head of the first vehicle A1 at each of the first position X1 and the second position X2, and the vehicle speed calculation unit 124 calculates the vehicle speed v1 of the first vehicle A1 based on the time difference t1 between the detection times of the head, but the present invention is not limited to this. In another embodiment, the first detection unit 121 may detect the tail of the first vehicle A1 at each of the first position X1 and the second position X2, and the vehicle speed calculation unit 124 may calculate the vehicle speed v1 of the first vehicle A1 based on the time difference between the detection times of the tail. When the vehicle speed v1 is calculated based on the time difference t1 between the detection times of the head, there is a possibility that some error occurs due to the acceleration of the vehicle length of the first vehicle A1. Therefore, the vehicle speed calculation unit 124 can reduce the error in the vehicle speed of the first vehicle A1 by calculating the vehicle speed v1 based on the time difference between the detection times of the tail. This allows the vehicle detector 10 to reduce calculation errors in the distance between the first vehicle A1 and the second vehicle A2, thereby suppressing deterioration in accuracy in determining whether the vehicles are combined.

[0071] In still another embodiment, the first detection unit 121 may detect the tail of the second vehicle A2 at each of the first position X1 and the second position X2, and the vehicle speed calculation unit 124 may calculate the vehicle speed v1 of the second vehicle A2 based on the time difference between the detection times of the tail.

[0072] <Third embodiment> Next, a vehicle detection system 1 and a vehicle detector 10 according to a third embodiment of the present disclosure will be described with reference to Fig. 10 to Fig. 12. Components common to the first and second embodiments will be denoted by the same reference numerals and detailed description thereof will be omitted.

[0073] (Overall composition) FIG. 10 is a diagram showing an overall configuration of a vehicle detection system according to the third embodiment of the present disclosure. As shown in FIG. 10, the vehicle detection system 1 according to this embodiment further includes a step board 20.

[0074] The step plate 20 is provided on the road surface of the lane L, extending in the lane width direction (Y direction). The installation position of the step plate 20 in the lane direction (X direction) is the same position (first position X1) as the reflective sensor 11 of the vehicle detector 10. The step plate 20 has multiple (for example, four) pressure sensors 21-24 arranged inside along the lane direction, and each of the pressure sensors 21-24 outputs a detection signal in response to being stepped on by the tires of the first vehicle A1.

[0075] (Functional configuration) FIG. 11 is a diagram illustrating a functional configuration of a vehicle detector according to the third embodiment of the present disclosure. As shown in FIG. 11, the acquisition unit 120 according to this embodiment further acquires detection signals output from the pressure sensors 21 to 24 of the step board 20.

[0076] Further, the vehicle detector 10 according to this embodiment executes the process of Fig. 7 in the same manner as in the second embodiment. In step 211 of Fig. 7, the vehicle speed calculation unit 124 calculates the vehicle speed of the first vehicle A1 based on the difference in output time of a plurality of detection signals related to a tire provided on one axle of the first vehicle A1 and the distance between each of the plurality of pressing sensors 21-24.

[0077] FIG. 12 is a diagram for explaining functions of the vehicle detector according to the third embodiment of the present disclosure. As shown in Fig. 12, after the first detection unit 121 detects the head of the first vehicle A1 at the first position X1 (step S202: YES in Fig. 7), the acquisition unit 120 acquires a detection signal from the tread 20. In the example of Fig. 12, the acquisition unit 120 acquires a detection signal from the pressure sensor 21 of the tread 20 at time ts10. Similarly, the acquisition unit 120 acquires detection signals from the pressure sensors 22, 23, and 24 of the tread 20 at times ts11, ts12, and ts13, respectively. The vehicle speed calculation unit 124 acquires detection signals in order from the pressure sensor 21 on the most upstream side (-X side) of the tread 20 to the pressure sensor 24 on the most downstream side (+X side), and then, when the detection signal is no longer output from the most downstream pressure sensor 24, stores the acquired series of detection signals in the storage medium 13 as tire detection information related to a tire provided on one axle of the first vehicle A1 (tire TY1 of the first axle in the example of FIG. 12).

[0078] 7, the vehicle speed calculation unit 124 calculates the vehicle speed v1 of the first vehicle A1 based on a plurality of detection signals related to the tire TY1 of the first vehicle A1. For example, the vehicle speed calculation unit 124 calculates the vehicle speed v1 of the first vehicle A1 based on the output time difference between the detection signals of the respective pressure sensors 21-24 of the tread 20 (time differences t10, t11, t12 in FIG. 12) and the distance between the pressure sensors 21-24.

[0079] The vehicle speed calculation unit 124 may calculate the vehicle speed v1 of the first vehicle A1 based on detection signals related to other tires instead of the tire TY1 of the first axle of the first vehicle A1. For example, the vehicle speed calculation unit 124 may overwrite the tire detection information in the storage medium 13 every time it acquires a series of detection signals related to each tire until the first detection unit 121 detects the tail of the first vehicle A1 (step S205: YES). In this case, the vehicle speed calculation unit 124 can calculate the vehicle speed v1 of the first vehicle A1 based on the tire detection information last detected (i.e., the tire TY2 of the rear end axle) immediately before the first vehicle A1 passes the first position X1.

[0080] Furthermore, the vehicle speed calculation unit 124 may calculate the vehicle speed v1 of the second vehicle A2 based on a detection signal of the tires of the second vehicle A2.

[0081] (Action and effect) As described above, in the vehicle detector 10 according to this embodiment, the acquisition unit 120 further acquires detection signals from the pressure sensors 21-24 of the tread 20. In addition, the vehicle speed calculation unit 124 calculates the vehicle speed v1 of the first vehicle A1 based on the difference in output time between a plurality of detection signals relating to a tire (TY1 or TY2 in FIG. 12) provided on one axle of the first vehicle and the distance between the pressure sensors 21-24.

[0082] In this way, the vehicle detector 10 can calculate the distance between the first vehicle A1 and the second vehicle A2 from the vehicle speed of the first vehicle A1. As a result, as in the second embodiment, it is possible to suppress a decrease in the accuracy of the determination caused by the fluctuation in the detection time difference between the first vehicle A1 and the second vehicle A2 according to the flow speed of the lane. It is possible to suppress a decrease in the accuracy of the determination as to whether the vehicles are combined.

[0083] The vehicle speed calculation unit 124 may also calculate the vehicle speed v1 of the first vehicle A1 based on a detection signal related to a tire TY2 provided on the rear end axle of the first vehicle A1.

[0084] In this way, the vehicle detector 10 can calculate the vehicle speed immediately before the first vehicle A1 passes the first position X1, and therefore can suppress an increase in error due to acceleration or deceleration of the first vehicle A1. This allows the vehicle detector 10 to reduce a calculation error in the inter-vehicle distance between the first vehicle A1 and the second vehicle A2.

[0085] <Hardware configuration> FIG. 13 is a diagram illustrating an example of a hardware configuration of a vehicle detector according to an embodiment of the present disclosure. As shown in FIG. 13, a computer 900 includes a CPU 901 , a main memory device 902 , an auxiliary memory device 903 , and an interface 904 .

[0086] The vehicle detector 10 according to each of the above-described embodiments is implemented in a computer 900. The operations of each of the above-described processing units are stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903, loads it in the main storage device 902, and executes the above-described processing in accordance with the program. The CPU 901 also secures storage areas in the main storage device 902 corresponding to each of the above-described storage units in accordance with the program.

[0087] 13 corresponds to the CPU 12 of the vehicle detector 10 according to each of the above-mentioned embodiments. Also, the auxiliary storage device 903 of Fig. 13 corresponds to the storage medium 13 of the vehicle detector 10 according to each of the above-mentioned embodiments.

[0088] The program may be for realizing a part of the functions to be performed by the computer 900. For example, the program may be for realizing the functions by combining with other programs already stored in the auxiliary storage device 903 or by combining with other programs implemented in other devices. In another embodiment, the computer 900 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions to be realized by the CPU 901 may be realized by the integrated circuit.

[0089] Examples of the auxiliary storage device 903 include a magnetic disk, a magneto-optical disk, an optical disk, and a semiconductor memory. The auxiliary storage device 903 may be an internal medium directly connected to the bus of the computer 900, or may be an external storage device 910 connected to the computer 900 via an interface 904 or a communication line. In addition, when the program is distributed to the computer 900 via a communication line, the computer 900 that receives the program may load the program into the main storage device 902 and execute the above-mentioned processing. In at least one embodiment, the auxiliary storage device 903 is a non-transitory tangible storage medium.

[0090] Furthermore, the program may be for realizing a part of the above-mentioned functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-mentioned functions in combination with another program already stored in the auxiliary storage device 903.

[0091] As described above, several embodiments of the present invention have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the spirit and technical scope of the invention.

[0092] <Additional Notes> The vehicle detector, the vehicle detection method, and the program described in the above-described embodiments can be understood, for example, as follows.

[0093] According to a first aspect of the present disclosure, a vehicle detector (10) includes an acquisition unit (120) that acquires sensor information from a sensor (11) installed at a first position in the lane direction, a first detection unit (121) that detects the tail of a first vehicle at the first position based on the sensor information, a second detection unit (122) that detects the head of a second vehicle at the first position following the detection of the tail of the first vehicle, and a determination unit (123) that determines whether the first vehicle and the second vehicle are a single coupled vehicle based on the elapsed time from detecting the tail of the first vehicle to detecting the head of the second vehicle.

[0094] Conventional vehicle detectors may erroneously recognize the first and second vehicles as a single coupled vehicle when exhaust gas is present between the first and second vehicles. However, the vehicle detector according to the above-described embodiment can appropriately determine whether the vehicles are coupled from the detection time difference between the first and second vehicles, even if an object is detected between the first and second vehicles. As a result, the vehicle detector can suppress erroneous recognition of two vehicles traveling in succession as a coupled vehicle consisting of a towing vehicle and a towed vehicle.

[0095] According to a second aspect of the present disclosure, in the vehicle detector (10) of the first aspect, the determination unit (123) determines that the first vehicle and the second vehicle are one connected vehicle when the elapsed time is equal to or less than a predetermined time.

[0096] In this way, when the first vehicle and the second vehicle are detected consecutively at an interval equal to or less than a predetermined time, the vehicle detector can appropriately determine that there is a higher possibility that these vehicles are coupled vehicles than that they are uncoupled vehicles, thereby reducing the possibility that the vehicle detector will erroneously distinguish between uncoupled vehicles and coupled vehicles.

[0097] According to a third aspect of the present disclosure, the vehicle detector (10) relating to the first aspect further includes a vehicle speed calculation unit (124) that calculates the vehicle speed of the first vehicle or the second vehicle based on the sensor information, and the determination unit (123) determines that the first vehicle and the second vehicle are a single connected vehicle when the distance from the tail of the first vehicle to the front of the second vehicle calculated from the elapsed time and the vehicle speed is equal to or shorter than a predetermined distance.

[0098] In this way, the vehicle detector can more accurately determine whether the first and second vehicles are combined vehicles by calculating the inter-vehicle distance between the first and second vehicles from the speed of the first or second vehicle and the detection time difference between the first and second vehicles. Even if the flow of traffic in the lane L slows down due to congestion, for example, the inter-vehicle distance should be maintained to some extent. Therefore, by determining whether the vehicles are combined vehicles based on the inter-vehicle distance, the vehicle detector can suppress a decrease in the accuracy of the determination caused by the fluctuation in the detection time difference between the first and second vehicles according to the flow speed of the lane.

[0099] According to a fourth aspect of the present disclosure, the vehicle detector (10) relating to the third aspect further includes, in addition to the first sensor (11) which is the sensor, a second sensor (14) installed at a second position downstream in the lane direction from the first position, and the first detection unit (121) further detects either the head or tail of the first vehicle and the head or tail of the second vehicle at each of the first position and the second position based on sensor information of the first sensor (11) and the second sensor (14), and the vehicle speed calculation unit (124) calculates the vehicle speed of the first vehicle based on the distance from the first position to the second position and the time from when the head or tail of the first vehicle or the second vehicle is detected at the first position to when it is detected at the second position.

[0100] According to a fifth aspect of the present disclosure, in the vehicle detector (10) relating to the third aspect, the acquisition unit (120) further acquires a detection signal output from a footboard (20) that is installed at the first position on the lane and has a plurality of pressure sensors (21-24) arranged along the lane direction, when the pressure sensors (21-24) are stepped on by a tire of the first vehicle, and the vehicle speed calculation unit (124) calculates the vehicle speed of the first vehicle based on the difference in output time of the plurality of detection signals related to a tire mounted on one axle of the first vehicle and the distance between the plurality of pressure sensors.

[0101] In this way, the vehicle detector can calculate the distance between the first vehicle A1 and the second vehicle A2 from the vehicle speed of the first vehicle A1. This makes it possible to suppress a decrease in accuracy in determining whether the vehicles are combined, which is influenced by fluctuations in the detection time difference between the first vehicle and the second vehicle according to the flow speed of the lane.

[0102] According to a sixth aspect of the present disclosure, in the vehicle detector (10) relating to the fifth aspect, the vehicle speed calculation unit (124) calculates the vehicle speed of the first vehicle based on the detection signal related to a tire provided on the rear axle of the first vehicle.

[0103] In this way, the vehicle detector can calculate the vehicle speed immediately before the first vehicle passes the first position, and therefore can suppress an increase in error due to acceleration or deceleration of the first vehicle. This allows the vehicle detector to reduce calculation errors in the distance between the first vehicle and the second vehicle.

[0104] According to a seventh aspect of the present disclosure, a vehicle detection method includes the steps of acquiring sensor information from a sensor (11) installed at a first position in a lane direction, detecting a tail of a first vehicle at the first position based on the sensor information, detecting a head of a second vehicle at the first position following the detection of the tail of the first vehicle, and determining whether the first vehicle and the second vehicle are a single coupled vehicle based on the elapsed time from detecting the tail of the first vehicle to detecting the head of the second vehicle.

[0105] According to an eighth aspect of the present disclosure, the program causes a computer (900) of a vehicle detector (10) to execute the following steps: acquiring sensor information from a sensor (11) installed at a first position in the lane direction; detecting the tail of a first vehicle at the first position based on the sensor information; detecting the head of a second vehicle at the first position following the detection of the tail of the first vehicle; and determining whether the first vehicle and the second vehicle are a single connected vehicle based on the elapsed time from detecting the tail of the first vehicle to detecting the head of the second vehicle. [Explanation of symbols]

[0106] 10 Vehicle detector 11 Reflective sensor (first reflective sensor, sensor, first sensor) 110 Light emitter / receiver section 12 CPU 120 Acquisition Department 121 First detection unit 122 Second detection unit 123 Judgment section 124 Vehicle speed calculation section 13 Storage medium 14 Second reflective sensor (second sensor) 140 Light emitter / receiver section 20 Treadboard 21, 22, 23, 24 Pressure sensor 900 Computers 901 CPU 902 Main storage 903 Auxiliary storage device 904 Interface 910 External storage device

Claims

1. an acquisition unit that acquires sensor information from a sensor installed at a first position in a lane direction; a first detection unit that detects a tail of the first vehicle at the first position based on the sensor information, and detects the presence or absence of an object other than a road surface at the first position after detecting the tail of the first vehicle; a second detection unit that detects a head of a second vehicle at the first position when an object other than a road surface is detected following the detection of the tail of the first vehicle; a determination unit that, when the first detection unit detects an object other than a road surface after detecting the tail of the first vehicle, determines whether the first vehicle and the second vehicle are a connected vehicle based on the elapsed time from detecting the tail of the first vehicle to detecting the head of the second vehicle; and A vehicle detector comprising:

2. The determination unit determines that the first vehicle and the second vehicle are a connected vehicle when the elapsed time is equal to or less than a predetermined time.

2. The vehicle detector of claim 1.

3. A vehicle speed calculation unit that calculates a vehicle speed of the first vehicle or the second vehicle based on the sensor information, the determination unit determines that the first vehicle and the second vehicle are a connected vehicle when a distance from a tail of the first vehicle to a head of the second vehicle, which is calculated from the elapsed time and the vehicle speed, is equal to or shorter than a predetermined distance.

2. The vehicle detector of claim 1.

4. In addition to the first sensor, a second sensor is further provided at a second position downstream of the first position in the lane direction, The first detection unit further detects one of a head or a tail of the first vehicle and a head or a tail of the second vehicle at each of the first position and the second position based on sensor information of the first sensor and the second sensor, the vehicle speed calculation unit calculates the vehicle speed of the first vehicle or the second vehicle based on a distance from the first position to the second position and a time from when the head or tail of the first vehicle or the second vehicle is detected at the first position to when it is detected at the second position; 4. A vehicle detector as claimed in claim 3.

5. The acquisition unit further acquires a detection signal output from a step plate that is installed at the first position on a lane and has a plurality of pressure sensors arranged along the lane direction when the pressure sensors are stepped on by tires of the first vehicle, the vehicle speed calculation unit calculates a vehicle speed of the first vehicle or the second vehicle based on a difference in output time of the plurality of detection signals related to a tire provided on one axle of the first vehicle and a distance between the plurality of pressure sensors.

4. A vehicle detector as claimed in claim 3.

6. The vehicle speed calculation unit calculates a vehicle speed of the first vehicle based on the detection signal related to a tire provided on an axle at the rear end of the first vehicle.

6. A vehicle detector as claimed in claim 5.

7. acquiring sensor information from a sensor installed at a first position in a lane direction; detecting a tail of the first vehicle at the first position based on the sensor information, and detecting the presence or absence of an object other than a road surface at the first position after detecting the tail of the first vehicle; detecting a head of a second vehicle at the first position when an object other than a road surface is detected following detection of the tail of the first vehicle; a step of determining whether or not the first vehicle and the second vehicle are a coupled vehicle based on an elapsed time from detecting the tail of the first vehicle to detecting the head of the second vehicle when an object other than the road surface is detected following the detection of the tail of the first vehicle; A vehicle detection method comprising:

8. acquiring sensor information from a sensor installed at a first position in a lane direction; detecting a tail of the first vehicle at the first position based on the sensor information, and detecting the presence or absence of an object other than a road surface at the first position after detecting the tail of the first vehicle; detecting a head of a second vehicle at the first position when an object other than a road surface is detected following detection of the tail of the first vehicle; a step of determining whether or not the first vehicle and the second vehicle are a coupled vehicle based on an elapsed time from detecting the tail of the first vehicle to detecting the head of the second vehicle when an object other than the road surface is detected following the detection of the tail of the first vehicle; A program that causes the vehicle detector's computer to execute the above.

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