Vehicle detector, vehicle detection method, and program

Abstract

To provide a vehicle detector capable of suppressing erroneous recognition that two vehicles traveling continuously is a combination vehicle consisting of a towing vehicle and a towed vehicle.SOLUTION: A vehicle detector includes: an acquisition section that acquires scanning information from a laser scanner installed on a roadside; a vehicle body detection section that identifies a detection range in a height direction of a detection object existing at a vehicle detection position on the basis of the scanning information and detects a tail of a vehicle traveling on a lane; a range identification section that identifies a determination target range for determining whether or not there is a towing bar on the basis of the scanning information after the tail of the vehicle is detected; and a determination section that determines whether or not one vehicle continues to travel on the basis of reflection intensity for a scanning angle and characteristics of the distribution of the reflection intensity in the determination target range of the scanning information.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] As a technology for detecting vehicles traveling on a lane, for example, a reflective vehicle detector is described in Patent Document 1. The reflective vehicle detector detects the presence or absence of a vehicle by projecting a laser beam toward the lane and receiving the reflected light from the vehicle, which is the detection target.

[0003] In addition, a vehicle may 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 one vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-181011 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, 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 lead to the detector mistakingly identifying the two vehicles traveling consecutively as a combined vehicle (towing vehicle and towed vehicle) and thinking that one vehicle is continuing to travel.

[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 scan information from a laser scanner installed on the roadside of a lane, a vehicle body detection unit that identifies a detection range in the height direction of an object to be detected present at a vehicle detection position based on the scan information and detects the tail of a vehicle traveling on the lane, a range identification unit that, after detecting the tail of the vehicle, identifies a determination target range in which the presence or absence of a towbar is determined based on the scan information, and a determination unit that determines whether a vehicle is continuing to travel based on the reflection intensity versus scanning angle and the characteristics of the distribution of the reflection intensity in the determination target range of the scan information.

[0008] According to one aspect of the present disclosure, a vehicle detection method includes the steps of acquiring scan information from a laser scanner installed on the roadside of a lane; determining a detection range in the height direction of a detection object present at a vehicle detection position based on the scan information, and detecting the tail of a vehicle traveling on the lane; after detecting the tail of the vehicle, determining a determination target range for determining the presence or absence of a towbar based on the scan information; and determining whether a vehicle is continuing to travel based on the reflection intensity versus scan angle and the characteristics of the distribution of the reflection intensity in the determination target range of the scan information.

[0009] 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 installed on the roadside of a lane; determining a detection range in the height direction of an object to be detected at a vehicle detection position based on the scan information, and detecting the tail of a vehicle traveling on the lane; after detecting the tail of the vehicle, determining a determination target range for determining whether or not a towbar is present based on the scan information; and determining whether or not a vehicle is continuing to travel based on the reflection intensity versus scan angle and the characteristics of the distribution of the reflection intensity in the determination target range of the scan information. 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 detector according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating a functional configuration of a vehicle detector according to an embodiment of the present disclosure. [Diagram 3] 5 is a flowchart illustrating an example of a process of a vehicle detector according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is a first diagram for explaining a function of a vehicle detector according to an embodiment of the present disclosure. [Diagram 5] FIG. 2 is a second diagram for explaining the function of the vehicle detector according to the embodiment of the present disclosure. [Figure 6] FIG. 13 is a third diagram for explaining the function of the vehicle detector according to the embodiment of the present disclosure. [Figure 7] FIG. 4 is a diagram illustrating a first characteristic of a distribution of reflection intensity according to an embodiment of the present disclosure. [Figure 8] FIG. 11 is a diagram illustrating a second characteristic of the distribution of reflection intensity according to an embodiment of the present disclosure. [Figure 9] FIG. 13 is a diagram illustrating a third characteristic of the distribution of reflection intensity according to an embodiment of the present disclosure. [Figure 10] 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] Hereinafter, a vehicle detector 10 according to an 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 detector according to an embodiment of the present disclosure. 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)". 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 is installed at a vehicle detection position X1 in the lane direction on the roadside (on island I) of lane L at the toll gate. The vehicle detector 10 detects whether or not 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.

[0015] (Functional configuration) FIG. 2 is a diagram illustrating a functional configuration of a vehicle detector according to an 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.

[0016] The laser scanner 11 projects a laser beam from the light projecting / receiving unit 110 to scan a predetermined scanning range R1 (FIG. 1), and detects a 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 a 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 a plurality of 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.

[0017] 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 range specification unit 121, a determination unit 122, and a vehicle body detection unit 123 by operating according to a predetermined program.

[0018] The acquisition unit 120 acquires scan information from the laser scanner 11 .

[0019] The range specifying unit 121 specifies a determination target range for determining the presence or absence of a tow bar based on the scan information.

[0020] The determination unit 122 determines whether or not a vehicle A is present at the vehicle detection position X1 based on the scan information. The determination unit 122 also determines whether or not a vehicle is continuing to travel based on the characteristics of the distribution of reflection intensity with respect to the scanning angle in the determination target range of the scan information.

[0021] Based on the scan information, the vehicle body detection unit 123 specifies a detection range in the height direction of detection objects present on the lane L, and detects the body (from the head to the tail) of the vehicle A traveling on the lane L. The detection objects include the body of the vehicle A (including the bodies, tires, etc. of the towing vehicle and towed vehicle, and the tow bar) and the exhaust gas of the vehicle A.

[0022] 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.

[0023] (Processing flow) FIG. 3 is a flowchart illustrating an example of processing by the vehicle detector according to an embodiment of the present disclosure. Hereinafter, the flow of processing by the vehicle detector 10 will be described with reference to FIG.

[0024] First, the determination unit 122 of the vehicle detector 10 sets the vehicle detection signal to a "vehicle not detected" state as an initial value (step S100).

[0025] The laser scanner 11 constantly scans the vehicle detection position X1 with a laser beam, and outputs scan information including a reflection position and reflection intensity of the irradiated laser beam for each scan. The acquisition unit 120 acquires the scan information output from the laser scanner 11 (step S101).

[0026] Next, the vehicle body detection unit 123 determines whether or not vehicle A is present at vehicle detection position X1 (whether or not the head of vehicle A has been detected) based on the acquired scan information (step S102). The vehicle body detection unit 123 according to this embodiment specifies 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).

[0027] For example, the result of scanning by the laser scanner 11 when the vehicle A does not exist 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. When 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 123 determines that the detection object exists at the reflection position. Note that, taking into account the measurement error of the laser scanner 11, the vehicle body detection unit 123 may determine that the detection object exists 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, when 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 123 determines that the vehicle A exists at the vehicle detection position X1 (the head of the 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, etc., so that the vehicle type discrimination device, etc. can know that the vehicle A has entered the lane L.

[0028] On the other hand, if the vehicle body detection unit 123 does not detect the detection object, or if the detection range in the height direction of the detected detection object is less than the vehicle head detection threshold and it is determined that vehicle A is not present (step S102: NO), it returns to step S100 and maintains the vehicle non-detection state.

[0029] Furthermore, 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 123 determines whether the tail of the towing vehicle has been detected based on the next scan information (step S105).

[0030] Specifically, the vehicle body detection unit 123 specifies a detection range in the height direction (Z direction in FIG. 1) of vehicle A from the scan information. If the currently specified detection range is lower than the previous detection range by a predetermined amount or more, the vehicle body detection unit 123 determines that it has detected the tail of the towing vehicle (step S105: YES). At this point, the vehicle body detection unit 123 cannot distinguish whether it has actually detected the tail of the towing vehicle of the articulated vehicles or the tail of the unarticulated vehicle. For this reason, the determination unit 122 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).

[0031] 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 123 determines that the body of vehicle A is present at vehicle detection position X1 (vehicle A detected in step S103 is traveling at vehicle detection position X1) (step S105: NO), and returns to step S103.

[0032] FIG. 4 is a first diagram for explaining a function of a vehicle detector according to an 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 uncoupled vehicles run continuously. Assume that the tail of the preceding vehicle A1 is detected by the vehicle body detection unit 123 at the time shown in FIG. 4. At this time, since there is no object blocking the laser light of the laser scanner 11 at the vehicle detection position X1, the determination unit 122 detects only the road surface of the lane L from the scan information (step S106: YES). In this case, the determination unit 122 determines that the vehicle A (the preceding vehicle A1) detected in steps S103 to S105 is not continuing to run (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 122 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 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.

[0033] FIG. 5 is a second diagram for explaining the function of the vehicle detector according to an embodiment of the present disclosure. As shown in Fig. 5, assume that vehicle A1 (tow vehicle) is traveling while towing towed vehicle A3. At this time, even after the tail of vehicle A1 passes vehicle detection position X1, tow bar B for towing towed vehicle A3 is present at vehicle detection position X1, and the laser light of laser scanner 11 is reflected or absorbed by tow bar B. When laser light is reflected by tow bar B, laser scanner 11 detects that the detection object is present at a position higher than the road surface (step S106: NO). Also, when laser light is absorbed by tow bar B, for example, laser scanner 11 does not receive laser light and therefore detects that the detection object is present at a position higher than the road surface (step S106: NO).

[0034] FIG. 6 is a third diagram for explaining the function of the vehicle detector according to an embodiment of the present disclosure. As shown in Fig. 6, it is assumed that two vehicles, vehicle A1 (preceding vehicle) and vehicle A2 (following vehicle), are traveling consecutively. It is also assumed that exhaust gas G of the preceding vehicle A remains at vehicle detection position X1 even after the preceding vehicle A1 passes vehicle detection position X1. In this case, the laser scanner 11 receives reflected light from the exhaust gas G of the preceding vehicle A1 even after the tail of the preceding vehicle A1 passes vehicle detection position X1. Then, after vehicle A1 passes vehicle detection position X1, the laser scanner 11 detects that a detection target exists at a position higher than the road surface by receiving reflected light from the exhaust gas G (step S106: NO).

[0035] 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 judgment unit 122 proceeds to the next step (S109) because there is a possibility that a towed vehicle is coupled to vehicle A (vehicle A1) detected in steps S103 to S105.

[0036] If the determination unit 122 determines that there is a possibility that a towed vehicle is coupled to the vehicle A (step S106: NO), the range determination unit 121 determines the determination target range of the tow bar B (step S109). Here, the range determination unit 121 determines the scanning range in which the presence of a target object other than the road surface is detected based on the scan information as the determination target range. In other words, the range determination unit 121 determines the scanning angle in which a target object other than the road surface of the lane L is detected as the determination target range.

[0037] Next, the determination unit 122 determines whether the target detection object included in the identified determination target range is a towbar based on the reflection intensity in the determination target range and the distribution characteristics of the reflection intensity. Specifically, the determination unit 122 first determines whether the reflection intensity (light amount) of the reflected light is below a predetermined first threshold at all scanning angles included in the determination target range (step S110).

[0038] FIG. 7 is a diagram illustrating a first characteristic of the distribution of reflection intensity according to an embodiment of the present disclosure. FIG. 7 shows an example of the distribution characteristics of the reflection intensity when the laser beam is irradiated from the light projecting / receiving unit 110 of the laser scanner 11 to the towing bar B having the characteristic of absorbing the laser beam, such as a black object. It is assumed that the laser beams P1 to P3 out of the multiple laser beams irradiated from the laser scanner 11 are irradiated onto the towing bar B. At this time, when the laser beams P1 to P3 are irradiated to the towing bar B made of a black object, they are absorbed by the towing bar B and are not reflected, or they reflect reflected beams P1' to P3' with extremely low reflected light amounts. Therefore, when the towing bar B is a black object, as shown in FIG. 7, a characteristic (first characteristic) appears in which the amount of reflected light for the laser beams P1 to P3 is extremely low (below the first threshold). Based on such a characteristic, the determination unit 122 determines that the towing bar B made of a black object has been detected (step S111) when the reflection intensity is below the first threshold in the entire determination target range (step S110: YES).

[0039] On the other hand, if the reflection intensity is equal to or greater than the first threshold in at least a part of the range to be determined (step S110: NO), the determination unit 122 further determines whether the variation in reflection intensity in the range to be determined is equal to or greater than a predetermined second threshold (step S112).

[0040] FIG. 8 is a diagram illustrating a second characteristic of the distribution of reflection intensity according to an embodiment of the present disclosure. FIG. 8 shows an example of the distribution characteristics of the reflection intensity when the laser beam is irradiated from the light projecting and receiving unit 110 of the laser scanner 11 to the towing bar B made of a glossy object. It is assumed that the laser beams P1 to P3 out of the multiple laser beams irradiated from the laser scanner 11 are irradiated onto the towing bar B. At this time, the reflected beams P1' to P3' of the laser beams P1 to P3 contain a large amount of regular reflection components. Then, as shown in FIG. 8, a characteristic (second characteristic) appears in which the reflection intensity of the reflected beam P2' of the laser beam P2 perpendicular to the surface of the towing bar B is significantly greater than the reflection intensity of the reflected beams P1' and P3' of the laser beams P1 and P3 not perpendicular to the surface of the towing bar B. Based on this characteristic, the determination unit 122 determines that the towing bar B made of a glossy object has been detected (step S113) when the variation in the reflection intensity of the reflected beams P1' to P3' included in the determination target range is equal to or greater than the second threshold value (step S112: YES). The variation in reflection intensity is expressed, for example, by the standard deviation of the reflection intensity.

[0041] When the tow bar B made of a black material is detected (S111) or when the tow bar B made of a shiny material is detected (S113), the determination unit 122 determines that the vehicle A detected in step S103 continues to travel (step S114). In this case, the vehicle detector 10 executes a process for when a towed vehicle is present (step S115). The process for when a towed vehicle is present is similar to the process in a conventional vehicle detector. For example, the determination unit 122 further repeatedly executes the processes of steps S103 to S108 until the vehicle A (tow vehicle A1 and towed vehicle A3) is no longer detected in step S115. Furthermore, the vehicle detector 10 notifies the vehicle type discrimination device or the like of a vehicle detection signal indicating that one vehicle A is continuing to travel until the towed vehicle A3 passes the vehicle detection position X1.

[0042] FIG. 9 is a diagram illustrating a third characteristic of the distribution of reflection intensity according to an embodiment of the present disclosure. FIG. 9 shows an example of the distribution characteristics of the reflection intensity when the laser beam is irradiated from the light projecting / receiving unit 110 of the laser scanner 11 to the tow bar B or the exhaust gas G other than a black object or a shiny object. For example, assume that the laser beams P1 to P3 of the multiple laser beams irradiated from the laser scanner 11 are irradiated to the exhaust gas G. At this time, the reflected beams P1′ to P3′ of the laser beams P1 to P3 are diffusely reflected on the exhaust gas G. Then, as shown in FIG. 9, a characteristic (third characteristic) appears in which the reflection intensities of the reflected beams P1′ to P3′ of the laser beams P1 to P3 are approximately the same. Note that, from this characteristic, it may be difficult to distinguish whether the target detected object detected by the laser scanner 11 is the tow bar B or the exhaust gas G. For this reason, when the variation in the reflection intensity of the reflected beams P1′ to P3′ included in the determination target range is less than the second threshold value (step S112: NO), the determination unit 122 determines that an unknown object has been detected (step S116).

[0043] When an unknown object is detected (step S116), the determination unit 122 determines that the vehicle A detected in step S103 is not continuing to travel, or that it is unclear whether the vehicle A is continuing to travel (step S117). In this case, the vehicle detector 10 executes a process for when there is no towed vehicle, or a process for when it is unclear (step S118). For example, in step S118, the determination unit 122 sets the vehicle detection signal to "vehicle not detected" and notifies other devices such as a vehicle type discrimination device. In addition, in step S118, the determination unit 122 may notify the vehicle type discrimination device, a monitoring panel at the toll gate office, and the like of a signal indicating that an unknown object has been detected, together with the vehicle detection signal indicating "vehicle not detected". For example, when the vehicle type discrimination device is notified that an unknown object has been detected, it transmits an image of the vehicle A captured by a camera, together with an instruction to confirm the presence or absence of a towed vehicle to the monitoring panel at the toll gate 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 take appropriate action to correct the type of vehicle A, the toll fee, etc.

[0044] (Hardware configuration) FIG. 10 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. 10, a computer 900 includes a CPU 901 , a main memory device 902 , an auxiliary memory device 903 , and an interface 904 .

[0045] The vehicle detector 10 according to the above-described embodiment is implemented in a computer 900. The operations 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 the above-described storage units in accordance with the program.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 10 corresponds to the CPU 12 (FIG. 2) of the vehicle detector 10 according to the above-described embodiment. Also, the auxiliary storage device 903 of FIG. 10 corresponds to the storage medium 13 (FIG. 2) of the vehicle detector 10 according to the above-described embodiment.

[0050] (Action and effect) As described above, the vehicle detector 10 according to this embodiment includes a range determination unit 121 that determines a determination range for determining the presence or absence of a towbar based on scan information, and a determination unit 122 that determines whether a vehicle is continuing to travel based on the reflection intensity versus scan angle and the characteristics of the reflection intensity distribution in the determination range.

[0051] In this way, the vehicle detector 10 can distinguish whether a tow bar is present or whether something that cannot be determined to be a tow bar is present, based on the characteristics of the distribution of reflection intensity. This allows the vehicle detector 10 to prevent erroneous detection of a tow bar due to the influence of exhaust gas. As a result, the vehicle detector 10 can prevent erroneous recognition of two vehicles traveling consecutively as a combination vehicle consisting of a towing vehicle and a towed vehicle.

[0052] Furthermore, when the reflection intensity is less than a predetermined first threshold value in the entire range of the determination target range, the determination unit 122 of the vehicle detector 10 determines that the vehicle is continuing to travel.

[0053] In this manner, when a vehicle is towing a towed vehicle with a towbar that has characteristics that make it difficult to reflect laser light (for example, a towbar made of black material), the vehicle detector 10 can accurately detect the presence of the towbar.

[0054] Furthermore, the determination unit 122 of the vehicle detector 10 determines that a vehicle is continuing to travel when the variation in reflection intensity in the determination target range is equal to or greater than a predetermined second threshold value.

[0055] In this manner, when a vehicle is towing a towed vehicle with a towbar that has the characteristic of producing a strong specular reflection light component (for example, a towbar made of a shiny material), the vehicle detector 10 can accurately detect the presence of the towbar.

[0056] In addition, the judgment unit 122 of the vehicle detector 10 judges that a vehicle is not continuing to travel if the reflection intensity is equal to or greater than the first threshold value throughout the entire range of the judgment target range and the variation in reflection intensity within the judgment target range is less than the second threshold value.

[0057] For example, when exhaust gas is present between two vehicles, a conventional vehicle detector may erroneously determine that these two vehicles are one vehicle (a combination vehicle consisting of a towing vehicle and a towed vehicle). However, the vehicle detector 10 according to this embodiment has the above-mentioned characteristics, and when it cannot reliably determine that a towbar is present, it treats these vehicles as two different vehicles. This makes it possible for the vehicle detector 10 to suppress erroneous determination that vehicle A is a combination vehicle due to the influence of exhaust gas.

[0058] In addition, when the reflection intensity is equal to or greater than the first threshold value throughout the entire range to be judged and the variation in reflection intensity within the range to be judged is less than the second threshold value, the judgment unit 122 of the vehicle detector 10 may judge that it is unclear whether a vehicle is continuing to travel and may notify that an unknown object has been detected.

[0059] In this way, the vehicle detector 10 can notify other devices, such as the vehicle type discrimination device and the monitoring panel at the toll booth office, that it has not been possible to determine whether a tow bar or exhaust gas is present. This makes it possible to inform the attendant at the toll booth office that there is a vehicle whose towed vehicle status is unclear, and to urge him or her to correct the vehicle type, toll fee, etc. of vehicle A.

[0060] 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.

[0061] <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.

[0062] 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) installed on the roadside of a lane, a vehicle body detection unit (123) that identifies a detection range in the height direction of a detection object present at a vehicle detection position based on the scan information and detects the tail of a vehicle traveling on the lane, a range identification unit (121) that, after detecting the tail of the vehicle, identifies a determination target range for determining the presence or absence of a towbar based on the scan information, and a determination unit (122) that determines whether a vehicle is continuing to travel based on the reflection intensity with respect to the scanning angle and the characteristics of the distribution of the reflection intensity in the determination target range of the scan information.

[0063] In this way, the vehicle detector can distinguish whether a tow bar is present or whether something that cannot be determined to be a tow bar is present, based on the characteristics of the distribution of reflection intensity. This makes it possible for the vehicle detector to prevent erroneous detection of a tow bar due to the influence of exhaust gas. As a result, the vehicle detector can prevent erroneous recognition of two vehicles as a combination vehicle consisting of a towing vehicle and a towed vehicle.

[0064] According to a second aspect of the present disclosure, in the vehicle detector (10) according to the first aspect, the judgment unit (122) judges that a vehicle is continuing to travel when the reflection intensity is less than a predetermined first threshold value in the entire range of the judgment target range.

[0065] In this manner, when a vehicle is towing a towed vehicle with a towbar that has characteristics that make it difficult to reflect laser light (for example, a towbar made of black material), the vehicle detector can accurately detect the presence of the towbar.

[0066] According to a third aspect of the present disclosure, in the vehicle detector (10) relating to the second aspect, the judgment unit (122) judges that a vehicle is continuing to travel if the reflection intensity in at least a part of the judgment target range is equal to or greater than the first threshold value and the variation in the reflection intensity throughout the entire judgment target range is equal to or greater than a predetermined second threshold value.

[0067] In this manner, when a vehicle is towing a towed vehicle with a towbar that has characteristics that produce a strong specular reflected light component (for example, a towbar made of a shiny material), the vehicle detector can accurately detect the presence of the towbar.

[0068] According to a fourth aspect of the present disclosure, in the vehicle detector (10) relating to the third aspect, when the reflection intensity in at least a part of the judgment target range is equal to or greater than the first threshold value and the variation in the reflection intensity in the entire judgment target range is less than the second threshold value, the judgment unit (122) judges that a vehicle is not continuing to travel or that it is unclear whether a vehicle is continuing to travel.

[0069] For example, if exhaust gas is present between two vehicles, a conventional vehicle detector may erroneously determine that these two vehicles are one vehicle (a combination vehicle consisting of a towing vehicle and a towed vehicle). However, the vehicle detector according to this embodiment has the above-mentioned characteristics, and if it cannot reliably determine that a towbar is present, it treats these vehicles as two different vehicles. This makes it possible for the vehicle detector to prevent erroneous determination that vehicle A is a combination vehicle due to the influence of exhaust gas.

[0070] According to a fifth aspect of the present disclosure, a vehicle detection method includes the steps of acquiring scan information from a laser scanner (11) installed on the roadside of a lane, determining a detection range in the height direction of a detection object present at a vehicle detection position based on the scan information, and detecting a tail of a vehicle traveling on the lane, and after detecting the tail of the vehicle, determining a determination target range for determining the presence or absence of a towbar based on the scan information, and determining whether a vehicle is continuing to travel based on the reflection intensity versus scan angle and the characteristics of the distribution of the reflection intensity in the determination target range of the scan information.

[0071] According to a sixth 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) installed on the roadside of a lane; identifying a detection range in the height direction of an object to be detected at a vehicle detection position based on the scan information, and detecting the tail of a vehicle traveling on the lane; after detecting the tail of the vehicle, identifying a determination target range for determining whether or not a towbar is present based on the scan information; and determining whether or not a vehicle is continuing to travel based on the reflection intensity versus scan angle and the characteristics of the distribution of the reflection intensity in the determination target range of the scan information. [Explanation of symbols]

[0072] 10 Vehicle detector 11 Laser scanner 110 Light emitter / receiver section 12 CPU 120 Acquisition Department 121 Range specification part 122 Judgment section 13 Storage medium 900 Computers 901 CPU 902 Main storage 903 Auxiliary storage device 904 Interface 910 External storage device

Claims

1. An acquisition unit that acquires scan information from a laser scanner installed on the roadside of a lane; a vehicle body detection unit that specifies a detection range in a height direction of a detection object present at a vehicle detection position based on the scan information and detects a tail of a vehicle traveling on the lane; a range determination unit that, after detecting the tail of the vehicle, determines a scanning angle at which a target object other than the road surface of the lane is detected based on the scan information as a determination target range for determining whether or not a tow bar is present; a determination unit that determines whether or not a vehicle is continuing to travel based on a reflection intensity with respect to a scanning angle and a distribution characteristic of the reflection intensity in the determination target range of the scan information; A vehicle detector comprising:

2. The determination unit determines that a vehicle is continuing to travel when the reflection intensity is less than a predetermined first threshold value in the entire determination range.

2. The vehicle detector of claim 1.

3. The determination unit determines that a vehicle is continuing to travel when the reflection intensity in at least a portion of the determination target range is equal to or greater than the first threshold value and a variation in the reflection intensity in the entire determination target range is equal to or greater than a predetermined second threshold value.

3. A vehicle detector as claimed in claim 2.

4. When the reflection intensity in at least a portion of the determination target range is equal to or greater than the first threshold value and the variation in the reflection intensity in the entire determination target range is less than the second threshold value, the determination unit determines that the vehicle is not continuing to travel or that it is unclear whether the vehicle is continuing to travel.

4. A vehicle detector as claimed in claim 3.

5. acquiring scan information from a laser scanner installed on the roadside of a lane; determining a detection range in a height direction of a detection object present at a vehicle detection position based on the scan information, and detecting a tail of a vehicle traveling on the lane; After detecting the tail of the vehicle, based on the scan information, a scan angle at which a target object other than the road surface of the lane is detected is identified as a determination target range for determining whether or not a tow bar is present; determining whether a vehicle is continuing to travel based on a reflection intensity versus a scanning angle and a distribution characteristic of the reflection intensity in the determination range of the scan information; A vehicle detection method comprising:

6. acquiring scan information from a laser scanner installed on the roadside of a lane; determining a detection range in a height direction of a detection object present at a vehicle detection position based on the scan information, and detecting a tail of a vehicle traveling on the lane; After detecting the tail of the vehicle, based on the scan information, a scan angle at which a target object other than the road surface of the lane is detected is identified as a determination target range for determining whether or not a tow bar is present; determining whether a vehicle is continuing to travel based on a reflection intensity versus a scanning angle and a distribution characteristic of the reflection intensity in the determination range of the scan information; A program that causes the vehicle detector's computer to execute the above.

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