JP7641866B2 - Vehicle detector, vehicle detection method, and program - Google Patents

Description

This disclosure relates to a vehicle detector, a vehicle detection method, and a program.

As a technology for detecting vehicles traveling on a lane, for example, Patent Document 1 describes a reflective vehicle detector. A reflective vehicle detector projects laser light toward the lane and detects the presence or absence of a vehicle by receiving reflected light from the vehicle, which is the object to be detected.

A vehicle may also be towing a towed vehicle connected by a towbar. If the vehicle detector detects the presence of a towbar, it will recognize the towing vehicle and towed vehicle as a single vehicle.

JP 2015-181011 A

Exhaust gas (water vapor) emitted from vehicles has the property of reflecting light. For this reason, if there is exhaust gas between two vehicles traveling consecutively, the vehicle detector will receive the light reflected by the exhaust gas and erroneously detect the presence of a tow bar between the vehicles, which could result in the two vehicles traveling consecutively being mistaken for a combined vehicle (towing vehicle and towed vehicle).

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.

According to one aspect of the present disclosure, the vehicle detector includes an acquisition unit that acquires scan information from a laser scanner that scans a scanning range set at a vehicle detection position on a lane, a vehicle body detection unit that identifies a detection range in the height direction of a detection object present at the vehicle detection position based on the scan information and detects the tail of a vehicle traveling on the lane, a contact determination unit that, after detecting the tail, determines whether or not a detection object on the lane is in contact with the road surface of the lane at the vehicle detection position based on the scan information, and a coupling determination unit that determines whether the vehicle is a coupled vehicle consisting of a towing vehicle and a towed vehicle based on a determination result of the contact determination unit.

According to one aspect of the present disclosure, the vehicle detection method includes the steps of acquiring scan information from a laser scanner that scans a scanning range set at a vehicle detection position on a lane, identifying a detection range in the height direction of a detection object present at the vehicle detection position based on the scan information and detecting the tail of a vehicle traveling on the lane, determining whether or not a detection object on the lane is in contact with the road surface of the lane at the vehicle detection position based on the scan information after detecting the tail, and determining whether or not the vehicle is a combination vehicle consisting of a towing vehicle and a towed vehicle based on the determination result of whether or not the detection object is in contact with the road surface.

According to one aspect of the present disclosure, the program causes a computer of a vehicle detector to execute the following steps: acquiring scan information from a laser scanner that scans a scanning range set at a vehicle detection position on a lane; identifying a detection range in the height direction of a detection object present at the vehicle detection position based on the scan information, and detecting the tail of a vehicle traveling on the lane; after detecting the tail, determining based on the scan information whether or not a detection object on the lane is in contact with the road surface of the lane at the vehicle detection position; and determining whether or not the vehicle is a combination vehicle consisting of a towing vehicle and a towed vehicle based on the determination result of whether or not the detection object is in contact with the road surface.

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.

1 is a diagram showing an overall configuration of a vehicle detection system according to a first embodiment of the present disclosure; 2 is a diagram illustrating a functional configuration of a vehicle detector according to the first embodiment of the present disclosure. FIG. 4 is a flowchart illustrating an example of a process of the vehicle detector according to the first embodiment of the present disclosure. FIG. 2 is a first diagram for explaining a function of a vehicle body detection unit according to the first embodiment of the present disclosure. FIG. 2 is a second diagram for explaining the function of the vehicle body detection unit according to the first embodiment of the present disclosure. FIG. 13 is a third diagram for explaining the function of the vehicle body detection unit according to the first embodiment of the present disclosure. FIG. 4 is a first diagram for explaining a process of a contact determination unit according to the first embodiment of the present disclosure. FIG. 13 is a second diagram for explaining the process of the contact determination unit according to the first embodiment of the present disclosure. FIG. 13 is a third diagram for explaining the process of the contact determination unit according to the first embodiment of the present disclosure. FIG. 4 is a fourth diagram for explaining the process of the contact determination unit according to the first embodiment of the present disclosure. FIG. 4 is a diagram showing a first characteristic of the distribution of reflection intensity according to the first embodiment of the present disclosure. FIG. 11 is a diagram showing a second characteristic of the distribution of reflection intensity according to the first embodiment of the present disclosure. FIG. 11 is a diagram illustrating an overall configuration of a vehicle detection system according to a second embodiment of the present disclosure. FIG. 11 is a diagram illustrating a functional configuration of a vehicle detector according to a second embodiment of the present disclosure. 10 is a flowchart illustrating an example of a process of a vehicle detector according to a second embodiment of the present disclosure. FIG. 11 is a first diagram for explaining a function of a connection determination unit according to a second embodiment of the present disclosure. FIG. 11 is a second diagram for explaining the function of the connection determination unit according to the second embodiment of the present disclosure. FIG. 2 is a diagram illustrating an example of a hardware configuration of a vehicle detector according to an embodiment of the present disclosure.

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. 1 to 12. FIG.

(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)".

As shown in FIG. 1, the vehicle detector 10 is installed at a vehicle detection position X1 in the lane direction on the roadside (on island I) of lane L at the toll booth. The vehicle detector 10 detects whether vehicle A is present at vehicle detection position X1. The vehicle detector 10 also outputs a vehicle detection signal (a signal indicating "vehicle detected" or "vehicle not detected") indicating the presence or absence of vehicle A to another device (not shown). Examples of other devices include a vehicle type discrimination device that discriminates the type of vehicle A, and 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.

(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 laser scanner 11, a CPU 12, and a storage medium 13.

The laser scanner 11 projects a laser beam from the light projecting/receiving unit 110 to scan a predetermined scanning range R1 (FIG. 1) set at the vehicle detection position X1 on the lane L, and detects the reflection position of the laser beam in the scanning range R1 based on the reflected light of the laser beam. As shown in FIG. 1, the scanning range R1 of the laser scanner 11 is a plane (YZ plane) perpendicular to the lane L at the vehicle detection position X1. The laser scanner 11 detects the reflection 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 laser scanner 11 also detects the reflection intensity (amount of reflected light) for each of the multiple scanning angles. The laser scanner 11 outputs the distance, YZ coordinate, and reflection intensity of the reflection position detected in one scan to the CPU 12 as scan information.

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 vehicle body detection unit 121, a contact determination unit 122, and a connection determination unit 123 by operating according to a predetermined program.

The acquisition unit 120 acquires scan information from the laser scanner 11.

The vehicle body detection unit 121, based on the scan information, identifies the detection range in the height direction of the detection object present on the lane L, and detects the body (from the front to the rear) of the vehicle A traveling on the lane L. The detection object includes the body of the vehicle A (including the body, tires, etc. of the towing vehicle and towed vehicle, and the tow bar) and the exhaust gas of the vehicle A.

After detecting the tail of vehicle A, the contact determination unit 122 determines whether or not a detection object on the lane is in contact with the road surface of lane L at vehicle detection position X1 based on the scan information.

The coupling determination unit 123 determines whether vehicle A is a coupled vehicle consisting of a towing vehicle and a towed vehicle based on the result of the determination of whether the detected object has come into contact with the road surface.

The storage medium 13 stores information acquired and generated by each part of the vehicle detector 10, information referenced in the processing of each part, etc.

(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.
The flow of processing by the vehicle detector 10 will be described below with reference to FIG.

First, the vehicle body detection unit 121 of the vehicle detector 10 sets the vehicle detection signal to a "vehicle not detected" state as the initial value (step S100).

The laser scanner 11 also constantly scans the vehicle detection position X1 with laser light, and outputs scan information for each scan including the reflection position and reflection intensity of the irradiated laser light relative to the scanning angle. The acquisition unit 120 acquires the scan information output from the laser scanner 11 (step S101).

Next, the vehicle body detection unit 121 determines whether vehicle A is present at vehicle detection position X1 (whether the head of vehicle A has been detected) based on the acquired scan information (step S102). The vehicle body detection unit 121 in this embodiment identifies a detection range in the height direction (Z direction in FIG. 1) of an object (detection target) present in lane L from the scan information, and determines whether this detection range is larger than or equal to a predetermined vehicle head detection threshold (step S102).

For example, the scan result by the laser scanner 11 when vehicle A is not present at the vehicle detection position X1, that is, the reflection position of the laser light on the road surface of the lane L (YZ coordinates, distance from the light projecting and receiving unit 110) is measured in advance and stored in the storage medium 13 as reference information. If the reflection position included in the scan information is higher than the road surface position of the lane L included in the reference information, the vehicle body detection unit 121 determines that a detection object is present at the reflection position. Note that, taking into account the measurement error of the laser scanner 11, the vehicle body 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. In addition, if the detection range in the height direction (Z direction in FIG. 1) of the detected detection object is equal to or larger than a predetermined vehicle head detection threshold, the vehicle body detection unit 121 determines that vehicle A is present at the vehicle detection position X1 (the head of vehicle A has been detected) (step S102: YES) and sets the vehicle detection signal to "vehicle detection" (step S103). This vehicle detection signal is sent to other devices such as a vehicle type discrimination device. This allows the vehicle type discrimination device to know that vehicle A has entered lane L.

On the other hand, if no object is detected, or if the detection range in the height direction of the detected object is less than the vehicle head detection threshold and it is determined that vehicle A is not present (step S102: NO), the vehicle body detection unit 121 returns to step S100 and maintains the vehicle non-detection state.

If the presence of vehicle A is detected (step S102: YES), the acquisition unit 120 further acquires the next scan information (step S104). The vehicle body detection unit 121 determines whether the tail of the towing vehicle has been detected based on the next scan information (step S105).

Specifically, the vehicle body detection unit 121 identifies the detection range in the height direction (Z direction in FIG. 1) of vehicle A from the scan information. If the currently identified detection range is lower than the previous detection range by a predetermined amount or more, the vehicle body detection unit 121 determines that it has detected the tail of the towing vehicle (step S105: YES). At this point, the vehicle body detection unit 121 cannot distinguish whether it has actually detected the tail of the towing vehicle of the articulated vehicle or the tail of the unarticulated vehicle. For this reason, the vehicle body detection unit 121 further determines whether the laser scanner 11 has detected only the road surface of lane L (i.e., whether it has detected the tail of the unarticulated vehicle) (step S106).

On the other hand, if the currently identified detection range is not lower than the previous detection range by a predetermined amount or more, the vehicle body detection unit 121 determines that vehicle A is present at vehicle detection position X1 (vehicle A detected in step S103 is traveling through vehicle detection position X1) (step S105: NO), and returns to step S103.

FIG. 4 is a first diagram for explaining the function of the vehicle body detection unit according to the first embodiment of the present disclosure.
FIG. 4 shows an example in which two vehicles A (a preceding vehicle A1 and a following vehicle A2) that are non-coupled vehicles run consecutively. As shown in FIG. 4, it is assumed that the tail of the preceding vehicle A1 is detected by the vehicle body detection unit 121 at time t0. At this time, since there is no object blocking the laser light of the laser scanner 11 at the vehicle detection position X1, the vehicle body detection unit 121 detects only the road surface of the lane L from the scan information (step S106: YES). In this case, the coupling determination unit 123 determines that the vehicle A (the preceding vehicle A1) detected in steps S103 to S105 is a non-coupled vehicle (step S107), and executes processing in the case where there is no towed vehicle (step S108). The processing in the case where there is no towed vehicle is similar to the processing in a conventional vehicle detector. For example, in step S108, the coupling 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 vehicle A (the preceding vehicle A1) has passed the vehicle detection position X1. After completing the process of step S108, the vehicle detector 10 executes the steps of FIG. 3 again for the following vehicle A2.

FIG. 5 is a second diagram for explaining the function of the vehicle body detection unit according to the first embodiment of the present disclosure.
Fig. 5 shows an example in which vehicle A, an unconnected vehicle, is emitting exhaust gas G. As shown in Fig. 5, it is assumed that the tail of vehicle A is detected by the vehicle body detection unit 121 at time t1. At this time, the laser light of the laser scanner 11 is reflected by exhaust gas G present at vehicle detection position X1, so that the vehicle body detection unit 121 detects a detection target, which is an object other than the road surface, at time t0 (step S106: NO).

FIG. 6 is a third diagram for explaining the function of the vehicle body detection unit according to the first embodiment of the present disclosure.
Fig. 6 shows an example in which vehicle A is traveling as a combined vehicle consisting of towing vehicle A1 and towed vehicle A3. As shown in Fig. 6, it is assumed that the tail of towing vehicle A1 is detected by the vehicle body detection unit 121 at time t2. At this time, the laser light of the laser scanner 11 is reflected by the tow bar B connecting towing vehicle A1 and towed vehicle A3, so that the vehicle body detection unit 121 detects a detection target that is an object other than the road surface at time t2 (step S106: NO).

As in the examples of Figures 5 and 6, if the laser scanner 11 detects an object other than the road surface (step S106: NO), the vehicle detector 10 proceeds to the next step (S109) because vehicle A detected in steps S103 to S105 may be an articulated vehicle.

Next, the contact determination unit 122 determines whether the object detected by the vehicle body detection unit 121 in step S106 has come into contact with the road surface (step S109).

FIG. 7 is a first diagram for explaining the process of the contact determination unit according to the first embodiment of the present disclosure.
FIG. 7 shows an example of the scan information at time t1 shown in FIG. 5. For example, the contact determination unit 122 divides the scanning range R1 (YZ plane) of the laser scanner 11 into areas of a size according to the pitch and measurement error of the laser scanner 11, and plots the reflection positions M included in the scan information in each of the divided areas. At this time, if the divided areas in which the reflection positions M are plotted are continuous up, down, left, right, and diagonally, the contact determination unit 122 labels these continuous reflection positions M as belonging to one object. From the scan information shown in FIG. 7, the contact determination unit 122 assigns different labels to the areas R2 and R3 and detects that objects exist in each of these areas. Among these, the reflection position M in the area R3 is plotted in the divided area representing the road surface, so the contact determination unit 122 detects that the object existing in the area R3 is the road surface. Furthermore, since a label different from that for region R3 is assigned to region R2, the contact determination unit 122 determines that the detection object present in region R2 is not in contact with the road surface (step S109: NO).

If it is determined that the object to be detected is not in contact with the road surface (step S109: NO), the vehicle detector 10 repeatedly acquires scan information (step S110), determines whether only the road surface has been detected (step S111), and determines whether the object to be detected has come into contact with the road surface (step S109) until the object to be detected comes into contact with the road surface or is no longer detected (only the road surface is detected). Note that the process of step S111 is the same as the process of step S106.

For example, suppose that exhaust gas G does not come into contact with the road surface. Or, suppose that vehicle A is equipped with a tow bar B but is not towing a towed vehicle A3. In this case, the contact determination unit 122 detects only the road surface without detecting the contact of the detection object with the road surface (step S109: NO and step S111: YES). In this case, the coupling determination unit 123 determines that this vehicle A is not a coupled vehicle (step S112). Then, the vehicle detector 10 executes processing for the case where there is no towed vehicle (step S113). The processing for the case where there is no towed vehicle is the same as the processing in a conventional vehicle detector. For example, in step S113, the coupling 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 to execute processing to discriminate the vehicle type of vehicle A.

FIG. 8 is a second diagram for explaining the process of the contact determination unit according to the first embodiment of the present disclosure.
FIG. 9 is a third diagram for explaining the process of the contact determination unit according to the first embodiment of the present disclosure.
FIG. 8 shows an example of the vehicle A and the exhaust gas G at a time point (time t1+n1) after the time n1 has elapsed from FIG. 5. The exhaust gas G is highly dense and concentrated immediately after being discharged from the muffler of the vehicle A, but tends to diffuse over time and come into contact with the road surface. As shown in FIG. 8, it is assumed that the exhaust gas G comes into contact with the road surface at the vehicle detection position X1 at time t1+n1. FIG. 9 shows an example of scan information measured at time t1+n1, in which the reflection position M included in the scan information is plotted in each divided area of the scanning range R1 (YZ plane). As shown in FIG. 8 and FIG. 9, since the exhaust gas G comes into contact with the road surface, the reflection position on the lower side (-Z side) of the exhaust gas G is plotted in a divided area adjacent to the divided area in which the road surface is detected. The contact determination unit 122 labels the area R4 consisting of these adjacent divided areas and detects that an object exists in this area R4. Since region R4 includes a divided region representing the road surface, the contact determination unit 122 determines that the detection object present in region R4 is in contact with the road surface (step S109: YES).

FIG. 10 is a fourth diagram for explaining the process of the contact determination unit according to the first embodiment of the present disclosure.
10 shows an example of combination vehicles A (towing vehicle A1 and towed vehicle A3) at a time point (time t2+n2) after a time n2 has elapsed from FIG. 6. As shown in FIG. 10, it is assumed that the tire T of the towed vehicle A3 comes into contact with the road surface at vehicle detection position X1 at time t2+n2. In this case, similar to the example in FIG. 9, the reflection position on the lower side (-Z side) of the tire T is plotted in a divided area adjacent to the divided area in which the road surface is detected. In this way, even when the tire T of the towed vehicle A3 reaches vehicle detection position X1, the contact determination unit 122 determines that the detection object detected from the scan information is in contact with the road surface (step S109: YES).

Next, the connection determination unit 123 determines whether the time from when the tail of vehicle A is detected (step S105: YES) until it is determined that the detected object has come into contact with the road surface is equal to or less than a predetermined threshold (step S114).

After being discharged from vehicle A, exhaust gas G may come into contact with the road surface within a very short time. On the other hand, when vehicle A is towing towed vehicle A3, it is assumed that the distance from the tail of towing vehicle A1 to the tire T of towed vehicle A3 is at least 2 m. Also, if vehicle A is traveling at a speed of 40 km/h, it takes about 0.18 seconds from when the tail of towing vehicle A1 passes vehicle detection position X1 until the tire T of towed vehicle A3 reaches vehicle detection position X1. Based on these assumptions, the coupling determination unit 123 sets the threshold to, for example, "0.18 seconds." Note that the coupling determination unit 123 may arbitrarily change the threshold depending on various conditions such as the speed limit of lane L and the average speed calculated from statistical data.

Let us assume that the time n1 from time t1 when the tail of vehicle A shown in FIG. 8 was detected to time t1+n1 when it was determined that the detected object (exhaust gas G) had come into contact with the road surface was less than or equal to the threshold value (step S114: YES). In this case, the coupling determination unit 123 determines that this detected object is exhaust gas G. Then, the coupling determination unit 123 determines that vehicle A detected in steps S103 to S105 is an uncoupled vehicle (step S116), and executes processing for the case where there is no towed vehicle (step S117). The processing content of step S117 is the same as that of step S108.

On the other hand, suppose that the time n2 from time t2 when the tail of the towing vehicle A1 shown in FIG. 10 was detected to time t2+n2 when it was determined that the detected object (tire T of the towed vehicle A3) had come into contact with the road surface exceeds the threshold (step S114: NO). Also suppose that it took some time for the exhaust gas G shown in FIG. 8 to come into contact with the road surface, and that the time n1 exceeds the threshold (step S114: NO). In these cases, the coupling determination unit 123 further determines whether the detected object is the exhaust gas G or the tire T of the towed vehicle A3 based on the scan information at the time when it was determined that the detected object had come into contact with the road surface (step S115).

FIG. 11 is a diagram showing a first characteristic of the distribution of reflection intensity according to the first embodiment of the present disclosure.
FIG. 11 shows an example in which the laser beam of the laser scanner 11 is irradiated onto the tire T (black portion) of the towed vehicle A3. For example, as shown in FIG. 11, among the multiple laser beams irradiated from the light emitting/receiving unit 110 of the laser scanner 11, the laser beams P1 to P3 are irradiated onto the black portion of the tire T. Since black objects absorb laser beams, the light emitting/receiving unit 110 of the laser scanner 11 cannot receive reflected light from the optical axis irradiated onto the black portion of the tire T, or receives very weak reflected light. Therefore, as in the example of FIG. 11, when the laser beams P1 to P3 are irradiated onto the black portion of the tire T, a feature (first feature) appears in which the light amount of the reflected beams P1' to P3' is extremely small (below a predetermined light amount). Note that, as shown in FIG. 4, when the leading vehicle A1 and the following vehicle A2 are running continuously, when the laser beam of the laser scanner 11 is irradiated onto the tire of the following vehicle A2, the reflected light feature as shown in FIG. 11 is also obtained.

Based on these characteristics, when there is a continuous light axis where the reflection intensity is less than a predetermined light amount (step S115: YES), the coupling determination unit 123 determines that the detected object is the tire T of the towed vehicle A3 or the tire of the following vehicle A2. In this case, the coupling determination unit 123 determines that the vehicle A detected in steps S103 to S105 is a coupled vehicle or a vehicle whose coupling or unconfirmed nature is unknown (step S118), and executes processing in the case where a towed vehicle is present or unknown (step S119). For example, in step S119, the coupling determination unit 123 notifies the vehicle type discrimination device, the monitoring panel of the toll booth office, etc. of a signal indicating that a vehicle whose coupling or unconfirmed nature is detected has been detected. When the vehicle type discrimination device is notified that a vehicle whose coupling or unconfirmed nature is detected has been detected, it transmits an image of the vehicle A taken by the camera, along with an instruction to confirm the presence or absence of a towed vehicle to the monitoring panel of the toll booth office (not shown). 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 appropriately adjust vehicle A's model, toll fee, etc.

FIG. 12 is a diagram showing a second characteristic of the distribution of reflection intensity according to the first embodiment of the present disclosure.
Fig. 12 shows an example in which the laser beam of the laser scanner 11 is irradiated onto the exhaust gas G. For example, as shown in Fig. 12, it is assumed that, of the multiple laser beams irradiated from the light projecting and receiving unit 110 of the laser scanner 11, the laser beams P1 to P3 are irradiated onto the exhaust gas G. Since the exhaust gas G reflects the laser beam, the light projecting and receiving unit 110 of the laser scanner 11 receives reflected light with a larger amount of light for the optical axis irradiated onto the exhaust gas G than when the optical axis is irradiated onto the black portion of the tire T. Therefore, when the laser beams P1 to P3 are irradiated onto the exhaust gas G as in the example of Fig. 12, a feature (second feature) appears in which the light amounts of the reflected beams P1' to P3' are equal to or greater than a predetermined light amount.

Considering these characteristics, if there is no point where there are consecutive light axes where the reflection intensity is less than the predetermined light amount (step S115: NO), the coupling determination unit 123 determines that the detected object is exhaust gas G. If this is the case, the coupling determination unit 123 determines that the vehicle A detected in steps S103 to S105 is a coupled vehicle (step S116), and executes processing for the case where there is no towed vehicle (step S117).

(Action and Effect)
As described above, the vehicle detector 10 according to this embodiment comprises an acquisition unit 120 that acquires scan information from the laser scanner 11, a vehicle body detection unit 121 that detects the tail of vehicle A based on the scan information, a contact determination unit 122 that, after detecting the tail, determines whether or not the detected object is in contact with the road surface of lane L, and a coupling determination unit 123 that determines that vehicle A is not a coupled vehicle based on the determination result of the contact determination unit 122.

In this way, the vehicle detector can estimate whether the detected object behind the tail of the vehicle is exhaust gas or part of the vehicle (tires) based on whether the detected object is in contact with the road surface. This makes it possible for the vehicle detector to prevent the presence of exhaust gas from mistakenly identifying two vehicles traveling consecutively as a combined vehicle (as one vehicle).

In addition, if the contact determination unit 122 does not determine that the detection object has come into contact with the road surface during the period from when the tail of the vehicle is detected until when the detection object is no longer detected, the coupling determination unit 123 determines that vehicle A is not a coupled vehicle.

By doing this, the vehicle detector 10 can determine that the vehicle A is not a combination vehicle even if the exhaust gas G does not come into contact with the road surface, or even if the vehicle A has a tow bar B attached but is not towing the towed vehicle A3.

In addition, the coupling determination unit 123 determines that vehicle A is not a coupled vehicle when it is determined that the detected object has come into contact with the road surface and the time from when the tail of the vehicle is detected until the detected object comes into contact with the road surface is equal to or less than a predetermined threshold value.

If vehicle A is a combined vehicle, it takes at least longer than the threshold time from when the tail of towing vehicle A1 is detected until it is determined that the tire T of towed vehicle A3 has come into contact with the road surface at vehicle detection position X1. On the other hand, exhaust gas G may diffuse and come into contact with the road surface in a short time less than the threshold. Based on this knowledge, if the vehicle detector 10 determines that the detected object has come into contact with the road surface after detecting the tail of vehicle A is less than the threshold time, that is, if it is certain that the detected object is exhaust gas G, it determines that vehicle A is not a combined vehicle. This makes it possible for the vehicle detector 10 to prevent the presence of exhaust gas G from causing the erroneous recognition of two vehicles traveling in succession as a combined vehicle (one vehicle).

The coupling determination unit 123 also determines that vehicle A is an uncoupled vehicle if the time from when the tail of the vehicle is detected until the detected object comes into contact with the road surface exceeds a predetermined threshold, and if there is no point in which the reflected light from the detected object contained in the scan information has a reflection intensity less than a predetermined light amount along a continuous optical axis.

In this way, if there are no consecutive optical axes where the reflection intensity is less than a predetermined amount of light, the vehicle detector 10 can determine that the object to be detected is exhaust gas, not a tire. This allows the vehicle detector 10 to accurately determine that vehicle A is a combined vehicle.

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. 13 to Fig. 17. Components common to the first embodiment will be denoted by the same reference numerals and detailed description will be omitted.

(Overall composition)
FIG. 13 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. 13 , the vehicle detection system 1 according to the present embodiment further includes a load measuring device 20 .

The load measuring device 20 is installed on the road surface of the lane L, extending in the lane width direction. The installation position of the load measuring device 20 in the lane direction is the same position (vehicle detection position X1) as the vehicle detector 10. The load measuring device 20 measures the load of the detection object at the vehicle detection position X1 and outputs it to the vehicle detector 10 as a load detection signal. The load measuring device 20 is, for example, a tread plate that detects the pressure (load) applied by the tires of the vehicle A (including the towing vehicle A1 and the towed vehicle A3). In another embodiment, the load measuring device 20 may be an axle load gauge that measures the load for each axle.

(Functional configuration)
FIG. 14 is a diagram illustrating a functional configuration of a vehicle detector according to the second embodiment of the present disclosure.
As shown in FIG. 14, the acquisition unit 120 according to this embodiment further acquires, from the load measuring device 20, a load detection signal capable of detecting the load of a detection object in contact with the road surface.

In addition, the coupling determination unit 123 determines that vehicle A is a coupled vehicle when the contact determination unit 122 determines that the detection object has come into contact with the road surface and the load of the detection object based on the load detection signal is equal to or greater than a predetermined value.

(Processing flow)
FIG. 15 is a flowchart illustrating an example of processing of the vehicle detector according to the second embodiment of the present disclosure.
The flow of processing by the vehicle detector 10 will be described below with reference to Fig. 15. The vehicle detector 10 according to this embodiment executes the processing of steps S215 to S216 instead of step S115 in the first embodiment (Fig. 3). The contents of the processing of steps S200 to S213 are similar to steps S100 to S113 in the first embodiment, respectively, and therefore will not be described. Unlike the first embodiment, this embodiment does not execute step S114 (processing for determining whether the time until the detection of contact of the detection object with the road surface is equal to or less than a threshold value) in the first embodiment.

After the tail of the towing vehicle is detected (step S205: YES), the acquisition unit 120 detects a detection object other than the road surface (step S206: NO) and, if this detection object comes into contact with the road surface at the vehicle detection position X1 (step S209: YES), acquires a load measurement signal from the load measuring device 20 at the time when it is determined that the detection object comes into contact with the road surface (step S215). This allows the acquisition unit 120 to acquire a load detection signal capable of detecting the load of the detection object that has come into contact with the road surface.

Next, the connection determination unit 123 determines whether the load of the detection object is equal to or greater than a predetermined value based on the acquired load measurement signal (step S216).

FIG. 16 is a first diagram for explaining the function of the connection determination unit according to the second embodiment of the present disclosure.
16 shows an example of vehicle A and exhaust gas G at a time point (time t1+n1) after a time n1 has elapsed from FIG. 5. In the example of FIG. 16, it is assumed that exhaust gas G is determined to have come into contact with the road surface at time t1+n1. Since exhaust gas G has no load, the load of the detection object at time t1+n1 when exhaust gas G comes into contact with the road surface (and load measuring device 20) is close to zero. Therefore, in the example of FIG. 16, the load of the detection object at time t1+n1 is less than a predetermined value (step S216: NO).

FIG. 17 is a second diagram for explaining the function of the connection determination unit according to the second embodiment of the present disclosure.
Figure 17 shows an example of combination vehicles A (towing vehicle A1 and towed vehicle A3) at a time (time t2+n2) after a time n2 has elapsed from Figure 6. As shown in Figure 17, it is assumed that a tire T of the towed vehicle A3 comes into contact with the road surface at vehicle detection position X1 at time t2+n2. At this time, a load corresponding to the axle load of the tire T of the towed vehicle A3 is applied to the load measuring device 20. Therefore, in the example of Figure 17, the load of the detection object at time t2+n2 is equal to or greater than a predetermined value (step S216: YES).

When the load of the detected object based on the load detection signal is less than a predetermined value (step S216: NO), the coupling determination unit 123 determines that the detected object is exhaust gas G. In this case, the coupling determination unit 123 determines that the vehicle A detected in steps S203 to S205 is an uncoupled vehicle (step S217), and executes processing for the case where there is no towed vehicle (step S218). The processing content of steps S217 to S218 is the same as S116 to S117 in the first embodiment (Figure 3), respectively.

On the other hand, if the load of the detected object based on the load detection signal is equal to or greater than a predetermined value (step S216: YES), the coupling determination unit 123 determines that the detected object is a tire of the towed vehicle A3. If so, the coupling determination unit 123 determines that the vehicle A detected in steps S203 to S205 is a coupled vehicle (step S219), and executes processing for when a towed vehicle is present (step S220). The processing content of steps S219 to S220 is the same as S118 to S119 in the first embodiment (Figure 3), respectively.

(Action and Effect)
As described above, in the vehicle detector 10 according to this embodiment, the acquisition unit 120 further acquires a load detection signal capable of detecting the load of the detection object that has come into contact with the road surface from the load measuring device 20, and the coupling determination unit 123 determines that vehicle A is a coupled vehicle when it is determined that the detection object has come into contact with the road surface and when the load of the detection object based on the load detection signal is equal to or greater than a predetermined value.

In this way, the vehicle detector 10 can accurately identify whether the detection object in contact with the road surface is exhaust gas G or the tires T of the towed vehicle A3 based on whether the detection object has a load equal to or greater than a predetermined value. This makes it possible for the vehicle detector 10 to prevent the two vehicles from being mistakenly identified as a combined vehicle due to the influence of exhaust gas G.

<Hardware Configuration>
FIG. 18 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. 18, a computer 900 includes a CPU 901 , a main memory device 902 , an auxiliary memory device 903 , and an interface 904 .

The vehicle detector 10 according to each of the above-mentioned embodiments is implemented in a computer 900. The operation of each of the above-mentioned processing units is 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, expands it in the main storage device 902, and executes the above-mentioned processing according to the program. The CPU 901 also secures memory areas in the main storage device 902 corresponding to each of the above-mentioned memory units according to the program.

The program may be for implementing part of the functions to be performed by the computer 900. For example, the program may be implemented by combining it with other programs already stored in the auxiliary storage device 903 or other programs implemented in other devices. In other embodiments, 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, part or all of the functions implemented by the CPU 901 may be implemented by the integrated circuit.

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 an external storage device 910 connected to the computer 900 via an interface 904 or a communication line. In addition, when this program is distributed to the computer 900 via a communication line, the computer 900 that receives the program may expand the program in 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.

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.

The CPU 901 in FIG. 18 corresponds to the CPU 12 (FIGS. 2 and 14) of the vehicle detector 10 according to each of the above-described embodiments. The auxiliary storage device 903 in FIG. 19 corresponds to the storage medium 13 (FIGS. 2 and 14) of the vehicle detector 10 according to the above-described embodiments.

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 variations are included in the spirit and technical scope of the invention.

For example, in the first embodiment described above, when the detection object comes into contact with the road surface (step S109: YES), it is determined that the time until the detection object comes into contact with the road surface exceeds a threshold (step S114: NO), and then a process of determining whether the detection object is a tire T or exhaust gas G based on the characteristics of the distribution of the reflection intensity of the detection object (step S115) is executed, but this is not limited to the above. In other embodiments, the process of step S114 may be omitted. At this time, when it is determined that the detection object has come into contact with the road surface (step S109: YES), the coupling determination unit 123 determines whether the detection object is an uncoupled vehicle, a coupled vehicle, or unknown based on the distribution of the reflection intensity of the detection object (step S115).

<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.

According to a first aspect of the present disclosure, a vehicle detector (10) includes an acquisition unit (120) that acquires scan information from a laser scanner (11) that scans a scanning range set at a vehicle detection position on a lane, a vehicle body detection unit (121) that identifies a detection range in the height direction of a detection object present at the vehicle detection position based on the scan information and detects the tail of a vehicle traveling on the lane, a contact determination unit (122) that, after detecting the tail, determines whether or not a detection object on the lane is in contact with the road surface of the lane at the vehicle detection position based on the scan information, and a coupling determination unit (123) that determines whether the vehicle is a coupled vehicle consisting of a towing vehicle and a towed vehicle based on the determination result of the contact determination unit (122).

In this way, the vehicle detector can estimate whether the detected object behind the tail of the vehicle is exhaust gas or part of the vehicle (tires) based on whether the detected object is in contact with the road surface. This makes it possible for the vehicle detector to prevent the presence of exhaust gas from mistakenly identifying two vehicles traveling consecutively as a combined vehicle (as one vehicle).

According to the second aspect of the present disclosure, in the vehicle detector (10) according to the first aspect, if the coupling determination unit (123) does not determine that the detection object has come into contact with the road surface during the period from when the tail of the vehicle is detected until when the detection object is no longer detected, the coupling determination unit determines that the vehicle is not a coupled vehicle.

In this way, the vehicle detector can determine that the vehicle is not a combination vehicle even if the exhaust gas does not come into contact with the road surface, or if the vehicle has a towbar attached but is not towing a towed vehicle.

According to a third aspect of the present disclosure, in the vehicle detector (10) according to the first or second aspect, the coupling determination unit (123) determines that the vehicle is not a coupled vehicle when it is determined that the detection object has come into contact with the road surface and the time from when the tail of the vehicle is detected until the detection object comes into contact with the road surface is equal to or less than a predetermined threshold.

In this way, if the time between detecting the tail of a vehicle and determining that the detected object has come into contact with the road surface is equal to or less than the threshold, that is, if it is certain that the detected object is exhaust gas, the vehicle detector will determine that the vehicles are not combined vehicles. This makes it possible to prevent the vehicle detector from mistakenly identifying two vehicles traveling consecutively as a combined vehicle (as one vehicle) due to the presence of exhaust gas.

According to a fourth aspect of the present disclosure, in the vehicle detector (10) according to any one of the first to third aspects, the coupling determination unit (123) determines that the vehicle is not a coupled vehicle when it is determined that the detection object has come into contact with the road surface and when there is no location in which the light axis at which the reflection intensity of the reflected light from the detection object included in the scan information is less than a predetermined light amount is continuous.

In this way, if there are no consecutive optical axes where the reflection intensity is less than a predetermined amount of light, the vehicle detector can determine that the object being detected is exhaust gas rather than a tire. This allows the vehicle detector to accurately determine that the vehicle is not an articulated vehicle.

According to a fifth aspect of the present disclosure, in the vehicle detector (10) according to any one of the first to third aspects, the coupling determination unit (123) determines that the vehicle is not a coupled vehicle if the time from when the tail of the vehicle is detected until when it is determined that the detected object has come into contact with the road surface exceeds a predetermined threshold, and if there is no point in which the light axis in which the reflection intensity of the reflected light from the detected object included in the scan information is less than a predetermined light amount is continuous.

By doing this, even in cases where it is difficult to determine whether the detection object is exhaust gas based solely on the time it takes for the detection object to come into contact with the road surface, if the detection object that comes into contact with the road surface can be identified as exhaust gas based on the reflection intensity, the vehicle detector can accurately determine that the vehicle is not an articulated vehicle.

According to a sixth aspect of the present disclosure, in the vehicle detector (10) according to the first or second aspect, the acquisition unit (120) further acquires a load detection signal capable of detecting the load of the detection object in contact with the road surface from a load measuring device (20) provided at the vehicle detection position on the lane, and the coupling determination unit (123) determines that the vehicle is a coupled vehicle when it is determined that the detection object is in contact with the road surface and when the load of the detection object based on the load detection signal is equal to or greater than a predetermined value.

In this way, it is possible to accurately identify whether the object being detected in contact with the road surface is exhaust gas or the tires of a towed vehicle based on whether the object is carrying a load equal to or greater than a predetermined value. This makes it possible for the vehicle detector to prevent the vehicle detector from mistakenly identifying two vehicles traveling in succession as a combined vehicle due to the influence of exhaust gas.

According to a seventh aspect of the present disclosure, the vehicle detection method includes the steps of acquiring scan information from a laser scanner (11) that scans a scanning range set at a vehicle detection position on a lane, identifying a detection range in the height direction of a detection object present at the vehicle detection position based on the scan information, and detecting the tail of a vehicle traveling on the lane, determining whether or not a detection object on the lane is in contact with the road surface of the lane at the vehicle detection position based on the scan information after detecting the tail, and determining whether or not the vehicle is a combination vehicle consisting of a towing vehicle and a towed vehicle based on the determination result of whether or not the detection object is in contact with the road surface.

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 scan information from a laser scanner (11) that scans a scanning range set at a vehicle detection position on a lane; identifying a detection range in the height direction of a detection object present at the vehicle detection position based on the scan information, and detecting the tail of a vehicle traveling on the lane; after detecting the tail, determining based on the scan information whether or not a detection object on the lane is in contact with the road surface of the lane at the vehicle detection position; and determining whether or not the vehicle is a combination vehicle consisting of a towing vehicle and a towed vehicle based on the determination result of whether or not the detection object is in contact with the road surface.

10 Vehicle detector 11 Laser scanner 110 Light projecting and receiving unit 12 CPU
120 Acquisition unit 121 Vehicle body detection unit 122 Contact determination unit 123 Connection determination unit 13 Storage medium 20 Load measurement device 900 Computer 901 CPU
902 Main storage device 903 Auxiliary storage device 904 Interface 910 External storage device

Claims (7)

an acquisition unit that acquires scan information from a laser scanner that scans a scanning range set at a vehicle detection position on a lane;
a vehicle body detection unit that specifies a detection range in a height direction of a detection object present at the vehicle detection position based on the scan information and detects a tail of a vehicle traveling on the lane;
a contact determination unit that, after detecting the tail of the vehicle, determines whether or not a detection object on the lane is in contact with a road surface of the lane at the vehicle detection position based on the scan information;
a coupling determination unit that determines whether the vehicle is a coupled vehicle including a towing vehicle and a towed vehicle based on a determination result of the contact determination unit;
Equipped with
the coupling determination unit determines that the vehicle is not an articulated vehicle when it is not determined that the detection object has come into contact with the road surface during a period from when the tail of the vehicle is detected until when the detection object is no longer detected.
Vehicle detector. the coupling determination unit determines that the vehicle is not an articulated vehicle when a time period from when the tail of the vehicle is detected until when it is determined that the detection object has come into contact with the road surface is equal to or shorter than a predetermined threshold value.
2. The vehicle detector of claim 1 . the coupling determination unit determines that the vehicle is not a coupled vehicle when it is determined that the detection object has come into contact with the road surface and when there is no location where there are consecutive light axes at which the reflection intensity of the reflected light from the detection object included in the scan information is less than a predetermined light amount.
A vehicle detector according to claim 1 or 2 . the coupling determination unit determines that the vehicle is not an articulated vehicle when a time from when the tail of the vehicle is detected until when it is determined that the detection object has come into contact with the road surface exceeds a predetermined threshold value, and when there is no location where there are consecutive light axes at which the reflection intensity of the reflected light from the detection object included in the scan information is less than a predetermined light amount.
A vehicle detector according to claim 1 or 2 . The acquisition unit further acquires a load detection signal capable of detecting a load of the detection object contacting the road surface from a load measuring device provided at the vehicle detection position on the lane,
the coupling determination unit determines that the vehicle is a coupled vehicle when it is determined that the detection object has contacted the road surface and when the load of the detection object based on the load detection signal is equal to or greater than a predetermined value.
2. The vehicle detector of claim 1 . acquiring scan information from a laser scanner that scans a scanning range set at a vehicle detection position on a lane;
determining a detection range in a height direction of an object to be detected that exists at the vehicle detection position based on the scan information, and detecting a tail of a vehicle traveling on the lane;
a step of determining whether or not a detection object on the lane is in contact with a road surface of the lane at the vehicle detection position based on the scan information after detecting the tail of the vehicle;
determining whether the vehicle is a combination vehicle including a towing vehicle and a towed vehicle based on a result of determining whether the detection object has come into contact with the road surface;
having
the determining step of determining whether the vehicle is an articulated vehicle includes determining that the vehicle is not an articulated vehicle if it is not determined that the detection object has come into contact with the road surface during a period from when the tail of the vehicle is detected until when the detection object is no longer detected.
Vehicle detection methods. acquiring scan information from a laser scanner that scans a scanning range set at a vehicle detection position on a lane;
determining a detection range in a height direction of an object to be detected that exists at the vehicle detection position based on the scan information, and detecting a tail of a vehicle traveling on the lane;
a step of determining whether or not a detection object on the lane is in contact with a road surface of the lane at the vehicle detection position based on the scan information after detecting the tail of the vehicle;
determining whether the vehicle is a combination vehicle including a towing vehicle and a towed vehicle based on a result of determining whether the detection object has come into contact with the road surface;
A program for causing a computer of a vehicle detector to execute the above,
the determining step of determining whether the vehicle is an articulated vehicle includes determining that the vehicle is not an articulated vehicle if it is not determined that the detection object has come into contact with the road surface during a period from when the tail of the vehicle is detected until when the detection object is no longer detected.
program .

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