JP7706396B2 - Vehicle length detector, vehicle length detection method, and program - Google Patents

Description

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

In recent years, technology has been developed that uses sensors to automatically measure the number of vehicles and their characteristics (external dimensions, number of axles, etc.).

For example, Patent Document 1 describes a technology that detects vehicles in a specified area from images captured by a camera and measures traffic volume.

Furthermore, at facilities used by vehicles, such as toll roads and parking lots, the usage fee may be changed depending on the size of the vehicle, and entry may be restricted. For example, toll booths on toll roads may be equipped with a vehicle length detection system that measures the length of the vehicle.

FIG. 11 is a diagram showing an example of a conventional vehicle length detection system.
11, the vehicle length detection system 9 has a vehicle detector 91 provided on the roadside (on island I) of lane L at the toll gate, and a vehicle length detector 92. The vehicle detector 91 is installed at an entry detection position X1 in the vehicle travel direction (±X direction) and detects whether or not vehicle A is present at the entry detection position X1. Based on the detection result of the vehicle detector 91, it is possible to detect that vehicle A has reached the entry detection position X1 and that vehicle A has passed the entry detection position X1.

The vehicle length detector 92 is installed at a specified position X2 downstream (+X side) of the vehicle detector 91 in the vehicle travel direction, and detects whether or not vehicle A is present at the specified position X2. The vehicle length detector 92 determines whether or not the length of vehicle A is equal to or greater than a threshold D1 based on the detection results of the vehicle detector 91 and its own detection results. For example, when determining whether vehicle A is a specified vehicle type, the threshold D1 is set based on the maximum vehicle length of the specified vehicle type. When the specified vehicle type is a light vehicle, the threshold D1 is set to, for example, 3.65 m, which is greater than the maximum vehicle length of a light vehicle. The specified position X2 is a position that is separated from the entry detection position X1 by the threshold D1.

When the vehicle length detector 92 detects that vehicle A is at (reaches) specified position X2 after the vehicle has passed entry detection position X1, it determines that the length of vehicle A is less than the threshold value. In addition, when the vehicle length detector 92 detects that vehicle A is at specified position X2 before vehicle A passes entry detection position X1, it determines that the length of vehicle A is equal to or greater than the threshold value. The result of the determination by the vehicle length detector 92 makes it possible to identify whether vehicle A is a specified vehicle type (light car).

JP 2017-151706 A

However, depending on the installation environment, such as the presence of an obstacle on island I, the vehicle length detector 92 may not be able to be placed at the specified position X2. For example, if the vehicle length detector 92 is placed upstream (on the -X side) of the specified position X2 to avoid an obstacle, the distance between the vehicle detector 91 (entry detection position X1) and the vehicle length detector 92 will be shorter than the threshold value D1. In that case, the vehicle length detector 92 may erroneously determine that the vehicle length of vehicle A is equal to or greater than the threshold value D1, even though vehicle A is a light vehicle (whose vehicle length is less than the threshold value D1).

The present disclosure has been made in consideration of these problems, and provides a vehicle length detector, a vehicle length detection method, and a program that can accurately detect whether a vehicle's length is equal to or greater than a threshold value, regardless of the installation environment of the vehicle length detector.

According to one aspect of the present disclosure, the vehicle length detector detects the length of a vehicle traveling on a lane, and includes: a first time acquisition unit that acquires a first time indicating the time when the vehicle passed the entry detection position based on a vehicle detection signal indicating whether the vehicle is present at the entry detection position of the lane; a second time acquisition unit that acquires a second time indicating the time when the vehicle reached the vehicle length determination position based on a vehicle length detection signal indicating whether the vehicle is present at the vehicle length determination position downstream of the entry detection position in the vehicle travel direction; an offset processing unit that offsets the second time by an offset amount according to the installation environment of the vehicle length detector; and a determination unit that determines that the vehicle length of the vehicle is equal to or greater than a threshold value if the second time after the offset is earlier than the first time.

According to one aspect of the present disclosure, a vehicle length detection method is a method for detecting the vehicle length of a vehicle traveling on a lane using a vehicle length detector, and includes the steps of acquiring a first time indicating the time when the vehicle passed the entry detection position based on a vehicle detection signal indicating whether the vehicle is present at the entry detection position of the lane, acquiring a second time indicating the time when the vehicle reached the vehicle length determination position based on a vehicle length detection signal indicating whether the vehicle is present at the vehicle length determination position downstream in the vehicle travel direction from the entry detection position, offsetting the second time by an offset amount according to the installation environment of the vehicle length detector, and determining that the vehicle length of the vehicle is equal to or greater than a threshold value if the second time after the offset is earlier than the first time.

According to one aspect of the present disclosure, the program causes a vehicle length detector that detects the length of a vehicle traveling on a lane to execute the steps of acquiring a first time indicating the time when the vehicle passed the entry detection position of the lane based on a vehicle detection signal indicating whether the vehicle is present at the entry detection position of the lane, acquiring a second time indicating the time when the vehicle reached the vehicle length determination position based on a vehicle length detection signal indicating whether the vehicle is present at the vehicle length determination position downstream in the vehicle travel direction from the entry detection position, offsetting the second time by an offset amount according to the installation environment of the vehicle length detector, and determining that the vehicle length of the vehicle is equal to or greater than a threshold value if the second time after the offset is earlier than the first time.

The vehicle length detector, vehicle length detection method, and program disclosed herein can accurately detect whether the vehicle length is equal to or greater than a threshold value, regardless of the installation environment of the vehicle length detector.

1 is a diagram showing an overall configuration of a vehicle length detection system according to a first embodiment of the present disclosure; 2 is a block diagram showing a functional configuration of a vehicle length detector according to a first embodiment of the present disclosure. FIG. 4 is a flowchart showing an example of processing of a vehicle length detector according to the first embodiment of the present disclosure. FIG. 2 is a first diagram for explaining a function of the vehicle length detector according to the first embodiment of the present disclosure. FIG. 2 is a first diagram showing an example of a vehicle detection signal and a vehicle length detection signal according to the first embodiment of the present disclosure. FIG. 2 is a second diagram for explaining the function of the vehicle length detector according to the first embodiment of the present disclosure. FIG. 2 is a second diagram showing an example of a vehicle detection signal and a vehicle length detection signal according to the first embodiment of the present disclosure. FIG. 4 is a diagram illustrating an example of an offset amount according to the first embodiment of the present disclosure. FIG. 11 is a diagram for explaining a function of a vehicle length detector according to a second embodiment of the present disclosure. 13A and 13B are diagrams illustrating an example of a vehicle detection signal and a vehicle length detection signal according to a second embodiment of the present disclosure. FIG. 1 is a diagram showing an example of a conventional vehicle length detection system.

First Embodiment
Hereinafter, a vehicle length detection system and a vehicle length detector according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 8. FIG.

(Overall composition)
FIG. 1 is a diagram showing an overall configuration of a vehicle length detection system according to a first embodiment of the present disclosure.
In the example of Fig. 1, the vehicle length detection system 1 is installed at a toll booth of a toll road, and measures the vehicle length of vehicle A traveling on lane L of the toll booth. The toll booth may also be equipped with a vehicle type discrimination device (not shown) that discriminates the vehicle type of vehicle A based on the vehicle length of vehicle A, and a toll collection system (not shown) that collects tolls according to the vehicle type. In other embodiments, the vehicle length detection system 1 may be installed in various facilities where it is necessary to measure the vehicle length to discriminate the vehicle type, such as parking lots that collect parking fees according to vehicle type, and roads where traffic restrictions are imposed on specific vehicle types.

As shown in FIG. 1, the vehicle length detection system 1 includes a vehicle detector 10 and a vehicle length detector 20.

The vehicle detector 10 is installed on the roadside (on island I) of lane L at entry detection position X1 in the vehicle travel direction (±X direction). The vehicle detector 10 is a so-called transmission type vehicle detector, and has a pair of a projector 11 and a receiver 12 installed opposite each other across lane L. The vehicle detector 10 outputs a vehicle detection signal that can distinguish the presence or absence of a vehicle at the entry detection position X1 based on whether the receiver 12 receives the light projected from the projector 11. While the receiver 12 is receiving light, the vehicle detector 10 outputs a vehicle detection signal (OFF) indicating that vehicle A is not present at the entry detection position X1. On the other hand, while the receiver 12 is not receiving light, the vehicle detector 10 outputs a vehicle detection signal (ON) indicating that vehicle A is present at the entry detection position X1.

The vehicle length detector 20 is installed on the roadside of the lane L (on island I) at a vehicle length determination position X3 downstream (+X side) of the entry detection position X1 in the vehicle travel direction. The vehicle length detector 20 has a pair of a projector 25 and a receiver 26, just like the vehicle detector 10. The vehicle length detector 20 outputs a vehicle length detection signal that can distinguish the presence or absence of a vehicle at the vehicle length determination position X3 based on whether the receiver 26 receives the light projected from the projector 25. While the receiver 26 is receiving light, the vehicle length detector 20 outputs a vehicle length detection signal (OFF) indicating that no vehicle is present at the vehicle length determination position X3. On the other hand, while the receiver 26 is not receiving light, the vehicle length detector 20 outputs a vehicle length detection signal (ON) indicating that a vehicle is present at the vehicle length determination position X3.

The vehicle length detector 20 according to this embodiment detects whether the vehicle length of vehicle A is equal to or greater than a threshold value D1. The threshold value D1 is set to a length that can distinguish whether the vehicle is a specified vehicle type. For example, if the specified vehicle type is a light vehicle, the threshold value D1 is set to a value greater than the maximum vehicle length of a light vehicle (e.g., 3.65 m).

When the vehicle length detection signal becomes "ON" while the vehicle detection signal is "ON" (vehicle A is at the entry detection position X1), the vehicle length detector 20 determines that the vehicle length of this vehicle A is equal to or greater than the threshold value D1. On the other hand, when the vehicle length detection signal becomes "ON" after the vehicle detection signal switches from "ON" to "OFF" (vehicle A has passed the entry detection position X1), the vehicle length detector 20 determines that the vehicle length of this vehicle A is less than the threshold value D1.

As shown in FIG. 11, the conventional vehicle length detector 92 had to be placed at a specified position X2 where the distance from the vehicle detector 91 (entry detection position X1) was a threshold value D1. However, as mentioned above, if an obstacle exists on the island I, the vehicle length detector 92 may not be able to be placed at the specified position X2.

Therefore, when the vehicle length detector 20 according to this embodiment is installed at a vehicle length determination position X3 different from the specified position X2, it adjusts the time at which the vehicle length detection signal turns "ON" according to the distance D2 from the entry detection position X1 to the vehicle length determination position X3 (or the distance D3 from the specified position X2 to the vehicle length determination position X3), thereby making it possible to accurately determine whether the vehicle length is equal to or greater than the threshold value D1, as if the vehicle length detector 20 were installed at the specified position X2.

(Functional configuration)
FIG. 2 is a block diagram showing a functional configuration of the vehicle length detector according to the first embodiment of the present disclosure.
As shown in FIG. 2 , the vehicle length detector 20 further includes a processor 21 , a memory 22 , a storage 23 , and a communication interface 24 .

The processor 21 operates according to a predetermined program to perform the functions of a first time acquisition unit 210, a second time acquisition unit 211, an offset processing unit 212, and a determination unit 213.

The first time acquisition unit 210 acquires a first time indicating the time when vehicle A passed the entry detection position X1 (when the vehicle detection signal switched from "ON" to "OFF") based on a vehicle detection signal indicating whether vehicle A is present at the entry detection position X1 of lane L.

The second time acquisition unit 211 acquires a second time indicating the time when vehicle A reaches vehicle length determination position X3 (when the vehicle length detection signal switches from "OFF" to "ON") based on the vehicle length detection signal indicating whether vehicle A is present at vehicle length determination position X3.

The offset processing unit 212 offsets the second time by an offset amount according to the installation environment of the vehicle length detector 20. The offset processing unit 212 according to this embodiment offsets the second time by an offset amount according to the distance from the entry detection position X1 to the vehicle length determination position X3.

The determination unit 213 determines that the vehicle length of vehicle A is equal to or greater than the threshold value D1 if the second time after the offset is earlier than the first time.

The predetermined program executed by the processor 21 is stored in a computer-readable recording medium. A computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, etc. The computer program may be distributed to a computer via a communication line, and the computer that receives the program may execute the program. Furthermore, the program may be for realizing part of the above-mentioned functions. Furthermore, the program may be a so-called differential file (differential program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

Memory 22 has memory space necessary for the operation of processor 21.

Storage 23 is a so-called auxiliary storage device, such as a hard disk drive (HDD) or a solid state drive (SSD).

The communication interface 24 is an interface for transmitting and receiving various signals to and from external devices. For example, the communication interface 24 receives a vehicle detection signal from the vehicle detector 10. In addition, if a vehicle type discrimination device (not shown) is provided at the toll booth, the communication interface 24 may transmit a signal indicating the determination result of the vehicle length detector 20 (whether or not the vehicle length of vehicle A is equal to or greater than the threshold value D1) to the vehicle type discrimination device.

(Processing flow)
FIG. 3 is a flowchart showing an example of processing of the vehicle length detector according to the first embodiment of the present disclosure.
An example of the processing of the vehicle length detector 20 will be described below with reference to FIG.

The first time acquisition unit 210 detects that vehicle A has entered entry detection position X1 of lane L based on the vehicle detection signal received from the vehicle detector 10 (step S10). Specifically, the first time acquisition unit 210 detects that vehicle A has entered entry detection position X1 when the vehicle detection signal received from the vehicle detector 10 switches from "OFF" to "ON."

Next, the first time acquisition unit 210 detects that vehicle A has passed the entry detection position X1 when the vehicle detection signal received from the vehicle detector 10 switches from "ON" to "OFF" (step S11).

The first time acquisition unit 210 also acquires the first time at which it is detected that vehicle A has passed the entry detection position X1 (step S12).

In parallel with the processing of the first time acquisition unit 210 (steps S10 to S12), the second time acquisition unit detects that vehicle A has reached the vehicle length determination position X3 based on the vehicle length detection signal (step S13). Specifically, the second time acquisition unit 211 detects that vehicle A has reached the vehicle length determination position X3 when the vehicle length detection signal switches from "OFF" to "ON."

The second time acquisition unit 211 also acquires the second time at which it is detected that vehicle A has reached the vehicle length determination position X3 (step S14).

Next, the offset processing unit 212 offsets the second time by an offset amount according to the distance D2 from the entry detection position X1 to the vehicle length determination position X3 (step S15).

FIG. 4 is a first diagram for explaining the function of the vehicle length detector according to the first embodiment of the present disclosure.
FIG. 5 is a first diagram showing an example of a vehicle detection signal and a vehicle length detection signal according to the first embodiment of the present disclosure.
First, as shown in FIG. 4, an example will be described in which the vehicle length determination position X3 is on the upstream side (−X side) of the specified position X2 in the vehicle traveling direction (distance D2<threshold value D1).

Vehicle A, as illustrated in FIG. 4, enters entry detection position X1 at time t1 and passes entry detection position X1 at time t3. Then, as shown in FIG. 5, the vehicle detection signal switches from "OFF" to "ON" at time t1, and switches from "ON" to "OFF" at time t3. At this time, the first time acquisition unit 210 acquires time t3 as the first time (step S12 in FIG. 3).

Furthermore, vehicle A shown in FIG. 4 reaches vehicle length determination position X3, which is the actual installation position of vehicle length detector 20, at time t2, which is before time t3. Then, the vehicle length detection signal switches from "OFF" to "ON" at time t2, as shown by the dashed line in FIG. 5. At this time, second time acquisition unit 211 acquires time t2 as the second time (step S14 in FIG. 3).

The offset processing unit 212 also determines the estimated time at which the vehicle length detection signal would switch to "ON" if the vehicle length detector 20 were installed at the specified position X2, based on the second time t2. Specifically, if the distance D2 from the entry detection position X1 to the vehicle length determination position X3 is shorter than the threshold value D1 (the vehicle length determination position X3 is upstream of the specified position X2), the offset processing unit 212 offsets the second time to delay it by a predetermined time (step S15 in FIG. 3). Then, as shown in FIG. 5, the timing at which the vehicle length detection signal switches to "ON" is offset to time t4, which is delayed by a predetermined time from the second time t2.

FIG. 6 is a second diagram for explaining the function of the vehicle length detector according to the first embodiment of the present disclosure.
FIG. 7 is a second diagram showing an example of a vehicle detection signal and a vehicle length detection signal according to the first embodiment of the present disclosure.
Next, an example will be described in which the vehicle length determination position X3 is downstream (+X side) of the specified position X2 in the vehicle travel direction (distance D2>threshold value D1) as shown in FIG.

Vehicle A shown in FIG. 6 enters entry detection position X1 at time t11 and passes entry detection position X1 at time t13. Then, as shown in FIG. 7, the vehicle detection signal switches from "OFF" to "ON" at time t11 and switches from "ON" to "OFF" at time t13. At this time, the first time acquisition unit 210 acquires time t13 as the first time (step S12).

Furthermore, vehicle A shown in FIG. 6 reaches vehicle length determination position X3, which is the actual installation position of vehicle length detector 20, at time t14, which is later than time t13. Then, the vehicle length detection signal switches from "OFF" to "ON" at time t14, as shown by the dashed line in FIG. 7. At this time, second time acquisition unit 211 acquires time t14 as the second time (step S14).

The offset processing unit 212 also determines the estimated time at which the vehicle length detection signal would switch to "ON" if the vehicle length detector 20 were installed at the specified position X2, based on the second time t14. Specifically, if the distance D2 from the entry detection position X1 to the vehicle length determination position X3 is longer than the threshold value D1 (the vehicle length determination position X3 is downstream of the specified position X2), the offset processing unit 212 offsets the second time to be earlier by a predetermined time (step S15). Then, as shown in FIG. 7, the timing at which the vehicle length detection signal switches to "ON" is offset to time t12, which is earlier by a predetermined time than the second time t14.

FIG. 6 is a diagram illustrating an example of an offset amount according to the first embodiment of the present disclosure.
The offset processing unit 212 determines the offset time (predetermined time) by referring to, for example, an offset amount table T1 (FIG. 6) previously recorded in the storage 23. As shown in FIG. 6, the offset amount table T1 associates the offset time with the distance D3 between the specified position X2 and the vehicle length determination position X3. For example, when the distance D3 is "-20 cm" (the vehicle length determination position X3 is disposed 20 cm upstream of the specified position X2), the offset time is "+v1" (delayed by v1 seconds). When the distance D3 is "0 cm", that is, when the vehicle length detector 20 is installed at the specified position X2, the offset time is "0 seconds". The vehicle length detector 20 records the value of the distance D3 input by the worker at the time of installation in the storage 23. The offset processing unit 212 determines the offset time based on the distance D3 recorded in the storage 23 and the offset amount table T1. When the location of the vehicle length detector 20 is changed, a new distance D3 is input by the worker. This allows the offset processing unit 212 to determine an appropriate offset time according to the changed arrangement of the vehicle length detector 20.

The storage 23 may also store an offset amount table T1 for each expected speed of the lane L. The expected speed is, for example, the speed limit of the lane L. In this case, the offset processing unit 212 extracts from the storage 23 the offset amount table T1 corresponding to the speed limit of the lane L input by the worker, and determines an offset time according to the distance D3.

Next, the determination unit 213 compares the first time with the second time after the offset (step S16). If the second time after the offset is before the first time (step S16; YES), that is, if it is estimated that the vehicle A reached the specified position X2 before passing the entry detection position X1, the determination unit 213 determines that the vehicle length of the vehicle A is equal to or greater than the threshold value D1 (step S17). On the other hand, if the second time after the offset is after the first time (step S16; NO), that is, if it is estimated that the vehicle A reached the specified position X2 after passing the entry detection position X1, the determination unit 213 determines that the vehicle length of the vehicle A is less than the threshold value D1 (step S18).

4 and 5, the vehicle length of vehicle A is shorter than the threshold value D1. For example, if the conventional vehicle length detector 92 is installed at the specified position X2, the timing when the vehicle length detection signal becomes "ON" is time t4. Since time t4 is later than the first time t3 when the vehicle detection signal becomes "OFF", the conventional vehicle length detector 92 can correctly determine that the vehicle length of vehicle A is shorter than the threshold value D1. However, as in the example of FIG. 4 and FIG. 5, if the vehicle length detector 92 is installed upstream (-X side) of the specified position X2, the vehicle length detection signal actually becomes "ON" at time t2 (second time) which is earlier than time t4. In this case, since the second time t2 is a time before the first time t3, there is a possibility that the conventional vehicle length detector 92 will erroneously determine that the vehicle length of vehicle A is equal to or greater than the threshold value D1.

In response to this, the offset processing unit 212 of the vehicle length detector 20 according to this embodiment offsets the second time t2 to be delayed by the amount that the distance D2 from the entry detection position X1 to the vehicle length determination position X3 becomes shorter than the threshold value D1 (step S15), as shown in Figures 4 and 5. This allows the offset processing unit 212 to simulate the time t4 at which the vehicle length detection signal of vehicle A is estimated to be "ON" if the vehicle length detector 20 is installed at the specified position X2.

As shown in FIG. 5, the time t4 after the offset is later than the first time t3 (step S16; NO), so the determination unit 213 can correctly determine that the length of vehicle A is shorter than the threshold value D1 (step S18). The vehicle length detector 20 according to this embodiment can accurately determine whether the length of vehicle A is equal to or greater than the threshold value D1, even when the vehicle length detector 20 is installed upstream of the specified position X2.

6 and 7, the vehicle length of vehicle A is longer than the threshold value D1. For example, if the conventional vehicle length detector 92 is installed at the specified position X2, the timing when the vehicle length detection signal becomes "ON" is time t12. Since time t12 is before the first time t13 when the vehicle detection signal becomes "OFF", the conventional vehicle length detector 92 can correctly determine that the vehicle length of vehicle A is equal to or longer than the threshold value D1. However, as in the examples of FIG. 6 and FIG. 7, if the vehicle length detector 92 is installed downstream (+X side) of the specified position X2, the vehicle length detection signal actually becomes "ON" at time t14 (second time), which is later than time t12. At this time, the conventional vehicle length detector 92 may erroneously determine that the vehicle length of vehicle A is shorter than the threshold value D1, since the second time t14 is later than the first time t13.

In response to this, the offset processing unit 212 of the vehicle length detector 20 according to this embodiment offsets the second time t14 to be earlier (step S15) in accordance with the amount by which the distance D2 from the entry detection position X1 to the vehicle length determination position X3 becomes longer than the threshold value D1, as shown in Figures 6 and 7. This allows the offset processing unit 212 to simulate the time t12 at which the vehicle length detection signal of vehicle A is estimated to be "ON" if the vehicle length detector 20 is installed at the specified position X2.

As shown in FIG. 7, the time t12 after the offset is a time before the first time t13 (step S16; YES), so the determination unit 213 can correctly determine that the vehicle length of this vehicle A is equal to or greater than the threshold value D1 (step S17). The vehicle length detector 20 according to this embodiment can accurately determine whether the vehicle length of vehicle A is equal to or greater than the threshold value D1, even when the vehicle length detector 20 is installed downstream of the specified position X2 in this manner.

(Action, Effect)
As described above, the vehicle length detector 20 according to this embodiment includes a first time acquisition unit 210 that acquires a first time indicating the time when the vehicle A passed the entry detection position X1 based on the vehicle detection signal of the vehicle detector 10, a second time acquisition unit 211 that acquires a second time indicating the time when the vehicle A reached the vehicle length determination position X3 based on the vehicle length detection signal, an offset processing unit 212 that offsets the second time by an offset amount according to the installation environment of the vehicle length detector 20, and a determination unit 213 that determines that the vehicle length of the vehicle A is equal to or greater than the threshold value D1 when the second time after the offset is earlier than the first time. Note that the installation environment in this embodiment is the positional relationship between the actual installation position of the vehicle length detector 20 (vehicle length determination position X3) and the specified position X2.

By doing this, even if the vehicle length detector 20 is installed at a position different from the specified position X2, it is possible to accurately determine whether the vehicle length of vehicle A is equal to or greater than the threshold value D1.

In addition, the offset processing unit 212 offsets the second time to delay it by a predetermined time when the distance D2 from the entry detection position X1 to the vehicle length determination position X3 is shorter than the threshold value D1.

By doing this, even if the vehicle length detector 20 is installed upstream of the specified position X2, it is possible to accurately determine whether the vehicle length of vehicle A is equal to or greater than the threshold value D1.

In addition, when the distance D2 from the entry detection position X1 to the vehicle length determination position X3 is longer than the threshold D1, the offset processing unit 212 offsets the second time to be earlier by a predetermined time.

By doing this, even if the vehicle length detector 20 is installed downstream of the specified position X2, it is possible to accurately determine whether the vehicle length of vehicle A is equal to or greater than the threshold value D1.

Second Embodiment
Next, a vehicle length detection system 1 according to a second embodiment of the present disclosure will be described. Components common to the first embodiment will be given the same reference numerals and detailed description will be omitted.

In the first embodiment, the processing in an installation environment in which the vehicle length detector 20 cannot be placed at the specified position X2 has been described. However, even if the vehicle length detector 20 can be placed at the specified position X2, there is a possibility that erroneous determination of vehicle length may be more frequent at toll gates where many vehicles with unusual shapes pass through than at other toll gates.

A vehicle with a special shape is, for example, a vehicle with a cargo that protrudes in the front-to-rear direction of the vehicle body. The cargo is, for example, a spare tire attached to the rear of the vehicle, a carrier, skis mounted on the carrier, or other detachable items. For example, at toll booths near ski resorts during certain times of the year, such as winter, it is expected that the number of vehicles with cargo such as skis attached will increase significantly.

Because such cargo can be removed, it is necessary to exclude it from the measurement of vehicle length. However, in the conventional vehicle length detection system 9, the vehicle detector 91 keeps the vehicle detection signal "ON" as long as the cargo is present at the entry detection position X1, even after the rear end of the vehicle body has passed the entry detection position X1. In other words, when there is cargo, the timing at which the vehicle detection signal turns "OFF" is delayed compared to when there is no cargo. As a result, the vehicle length detector 92 may erroneously determine that the vehicle length is equal to or greater than the threshold value D1, even if the vehicle length is actually less than the threshold value D1.

Therefore, the vehicle length detector 20 according to this embodiment can prevent the accuracy of vehicle length determination from being reduced due to the influence of cargo by adjusting the time when the vehicle length detection signal turns "ON" in locations where many vehicles carrying cargo are traveling.

FIG. 9 is a diagram for explaining the function of the vehicle length detector according to the second embodiment of the present disclosure.
FIG. 10 is a diagram illustrating an example of a vehicle detection signal and a vehicle length detection signal according to the second embodiment of the present disclosure.
The process of the vehicle length detector 20 will be described in detail below with reference to FIGS. 9 and 10 and FIG.

For example, as shown in FIG. 9, assume that a load B (spare tire) is attached to the rear of vehicle A. In the example of FIG. 9, vehicle A enters entry detection position X1 at time t21, and the vehicle detection signal turns "ON." In addition, the rear end of vehicle A passes the entry detection position at time t22, but because the presence of the load is detected by vehicle detector 91, the vehicle detection signal turns "OFF" at time t24, when the load passes entry detection position X1. Therefore, the first time acquisition unit 210 acquires time t24 as the first time (step S12 in FIG. 3).

Furthermore, vehicle A reaches specified position X2 (vehicle length determination position X3) at time t23, at which point the vehicle length detection signal turns "ON." Therefore, the second time acquisition unit 211 acquires time t23 as the second time (step S14 in FIG. 3).

Also, assuming that vehicle A is carrying load B, the offset processing unit 212 determines the estimated time at which the vehicle length detection signal will switch to "ON" if load B is removed. Specifically, the offset processing unit 212 offsets the second time to delay it by a predetermined time, taking into account the delay in the timing at which the vehicle detection signal switches to "OFF" due to the loading of load B (step S15 in FIG. 3). Then, as shown in FIG. 10, the timing at which the vehicle length detection signal switches to "ON" is offset to time t25, which is delayed by a predetermined time from the second time t23.

The offset processing unit 212 offsets the second time based on, for example, an offset time (predetermined time) that is pre-recorded in the storage 23. The offset time is set in advance based on, for example, the maximum length of the load B determined by legal regulations (for example, a length equivalent to one-tenth of the maximum vehicle length of a light vehicle).

In addition, the storage 23 may record an offset time for each assumed speed of the lane L. The assumed speed is, for example, the speed limit of the lane L. In this case, the offset processing unit 212 reads out the offset time corresponding to the speed limit of the lane L input by the operator from the storage 23 and performs the offset processing.

Next, the determination unit 213 compares the first time with the second time after the offset (step S16 in FIG. 3). If the second time after the offset is before the first time (step S16 in FIG. 3; YES), the determination unit 213 determines that the vehicle length of vehicle A is equal to or greater than the threshold value D1 (step S17 in FIG. 3). On the other hand, if the second time after the offset is after the first time (step S16; NO), the determination unit 213 determines that the vehicle length of vehicle A is less than the threshold value D1 (step S18 in FIG. 3).

In the examples of Figures 9 and 10, the vehicle length of vehicle A excluding the cargo is assumed to be shorter than threshold value D1. However, the vehicle detection signal does not turn "OFF" until cargo B of vehicle A passes the entry detection position X1. Therefore, the second time t23 at which the vehicle length detection signal turns "ON" is before the first time t24 at which the vehicle detection signal turns "OFF". As a result, the conventional vehicle length detector 92 may erroneously determine that the vehicle length of vehicle A is greater than or equal to threshold value D1.

In response to this, the offset processing unit 212 of the vehicle length detector 20 according to this embodiment, as shown in Figures 9 and 10, assumes that vehicle A is carrying cargo B and offsets the second time t2 to delay it by a predetermined time (step S15 in Figure 3). This allows the offset processing unit 212 to simulate the time t25 at which the vehicle length detection signal of vehicle A is estimated to turn "ON" if vehicle A removes cargo B.

As shown in FIG. 10, the time t25 after the offset is later than the first time t24 (step S16 in FIG. 3; NO), so the determination unit 213 can correctly determine that the length of this vehicle A is shorter than the threshold value D1 (step S18 in FIG. 3). The vehicle length detector 20 according to this embodiment can reduce the possibility of erroneously determining that the length of vehicle A is equal to or greater than the threshold value D1 at a toll gate where vehicle A is often carrying cargo B.

In another embodiment, an operator may be able to set whether to enable or disable the process of offsetting the second time. For example, at a toll booth near a ski resort, an operator may enable the offset process during periods when the number of vehicles carrying cargo increases, such as in winter, and disable the offset process during other periods. This switching between enable and disable may be performed manually by the operator, or the offset processing unit 212 may be set to automatically enable only during a set period.

(Action, Effect)
As described above, in the vehicle length detector 20 of this embodiment, the offset processing unit 212 offsets the second time to delay it by a predetermined time when the vehicle length detector 20 is installed in an installation environment in which a vehicle A carrying cargo B is traveling.

By doing this, the vehicle length detector 20 can reduce the possibility of erroneously determining that the vehicle length of vehicle A is equal to or greater than threshold value D1 in locations where vehicle A is often carrying cargo B.

As described above, several embodiments of the present disclosure 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 gist of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and gist of the invention.

For example, in each of the above-mentioned embodiments, the offset time according to the assumed speed is set in advance, and the offset processing unit 212 uses the speed limit of the lane L as the assumed speed of the lane L, but the present invention is not limited to this. In other embodiments, the offset processing unit 212 may record the speeds of multiple vehicles traveling on the lane L, and use the average speed calculated from statistical information on the speeds of the multiple vehicles as the assumed speed. The offset processing unit 212 calculates the speed of each vehicle based on, for example, the distance D2 from the entry detection position X1 to the vehicle length determination position X3 and the time from when the vehicle detection signal becomes "ON" to when the vehicle length detection signal becomes "ON", and records the calculated speed in the storage 23. When a predetermined number or more of speed samples are recorded, the offset processing unit 212 calculates the average speed of these speed samples and uses it as the assumed speed. The offset processing unit 212 may also calculate the average speed for each season, day of the week, and time period, and use the average speed according to the current date and time as the assumed speed. This allows the offset processing unit 212 to more accurately adjust the offset time according to the actual speed of the vehicle traveling on lane L.

The vehicle length detector 20 may also record the time when the vehicle detection signal switches between "ON" and "OFF", the time when the vehicle length detection signal switches between "ON" and "OFF", the offset time used in the offset process, the vehicle length determination result, and the like, as a log in the storage 23. When the vehicle length detector 20 is connected to a maintenance computer (not shown), it may transmit the log recorded in the storage 23 so that an operator can check it via the maintenance computer. The operator determines whether the offset time is appropriate based on the timing of switching the vehicle detection signal and the vehicle length detection signal, the vehicle length determination result, and the like. For example, assume that the distance D3 between the specified position X2 and the vehicle length determination position X3 is "-20 cm" and the offset time was set to "+v1" based on the offset amount table T1 in FIG. 8. If the operator determines that the current offset time ("+v1") causes many errors in the vehicle length determination result, he or she transmits an instruction (signal) to change the offset time via the maintenance computer. For example, if the operator specifies another offset time "+v2", the vehicle length detector 20 (offset processing unit 212) performs offset processing using the specified offset time "+v2" in subsequent processing. This allows the vehicle length detector 20 to improve its determination accuracy.

<Additional Notes>
The vehicle length detector, the vehicle length 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 length detector (20) detects the length of a vehicle traveling on a lane, and includes: a first time acquisition unit that acquires a first time indicating the time when the vehicle passed the entry detection position on the basis of a vehicle detection signal indicating whether the vehicle is present at the entry detection position of the lane; a second time acquisition unit that acquires a second time indicating the time when the vehicle reached the vehicle length determination position on the basis of a vehicle length detection signal indicating whether the vehicle is present at the vehicle length determination position downstream of the entry detection position in the vehicle travel direction; an offset processing unit that offsets the second time by a predetermined offset amount according to the installation environment of the vehicle length detector; and a determination unit that determines that the vehicle length of the vehicle is equal to or greater than a threshold value if the second time after the offset is earlier than the first time.

According to a second aspect of the present disclosure, in the vehicle length detector (20) according to the first aspect, the offset processing unit offsets the second time to delay it by a predetermined time when the distance from the entry detection position to the vehicle length determination position is shorter than the threshold value.

According to a third aspect of the present disclosure, in the vehicle length detector (20) according to the first or second aspect, the offset processing unit offsets the second time to be earlier by a predetermined time when the distance from the entry detection position to the vehicle length determination position is longer than the threshold value.

According to a fourth aspect of the present disclosure, in the vehicle length detector (20) according to any one of the first to third aspects, the offset processing unit offsets the second time to delay it by a predetermined time when the vehicle length detector is installed in the installation environment in which the vehicle travels, the vehicle having a load protruding in the fore-and-aft direction of the vehicle body.

According to a fifth aspect of the present disclosure, in the vehicle length detector (20) according to any one of the second to fourth aspects, the offset processing unit changes the offset amount according to the expected speed of the vehicle.

According to the sixth aspect of the present disclosure, in the vehicle length detector (20) according to the fifty-first aspect, the offset processing unit determines the assumed speed based on statistical information on the speeds of the multiple vehicles traveling on the lane.

According to a seventh aspect of the present disclosure, a vehicle length detection method is a method for detecting the vehicle length of a vehicle traveling on a lane using a vehicle length detector (20), and includes the steps of acquiring a first time indicating the time when the vehicle passed the entry detection position of the lane based on a vehicle detection signal indicating whether the vehicle is present at the entry detection position of the lane, acquiring a second time indicating the time when the vehicle reached the vehicle length determination position based on a vehicle length detection signal indicating whether the vehicle is present at the vehicle length determination position downstream in the vehicle travel direction from the entry detection position, offsetting the second time by an offset amount according to the installation environment of the vehicle length detector, and determining that the vehicle length of the vehicle is equal to or greater than a threshold value if the second time after the offset is earlier than the first time.

According to an eighth aspect of the present disclosure, the program causes a vehicle length detector (20) that detects the length of a vehicle traveling on a lane to execute the steps of: acquiring a first time indicating the time when the vehicle passed the entry detection position of the lane based on a vehicle detection signal indicating whether the vehicle is present at the entry detection position of the lane; acquiring a second time indicating the time when the vehicle reached the vehicle length determination position based on a vehicle length detection signal indicating whether the vehicle is present at the vehicle length determination position downstream in the vehicle travel direction from the entry detection position; offsetting the second time by an offset amount according to the installation environment of the vehicle length detector; and determining that the vehicle length of the vehicle is equal to or greater than a threshold value if the second time after the offset is earlier than the first time.

Reference Signs List 1 Vehicle length detection system 10 Vehicle detector 11 Light projector 12 Light receiver 20 Vehicle length detector 21 Processor 210 First time acquisition unit 211 Second time acquisition unit 212 Offset processing unit 213 Determination unit 22 Memory 23 Storage 24 Communication interface 25 Light projector 26 Light receiver

Claims (7)

A vehicle length detector for detecting the length of a vehicle traveling on a lane,
a first time acquisition unit that acquires a first time indicating a time when the vehicle passed the lane entry detection position based on a vehicle detection signal indicating whether the vehicle is present at the lane entry detection position;
a second time acquisition unit that acquires a second time indicating a time when the vehicle reaches the vehicle length determination position based on a vehicle length detection signal indicating whether the vehicle is present at the vehicle length determination position downstream of the entry detection position in a vehicle traveling direction;
an offset processing unit that offsets the second time by an offset amount according to an installation environment of the vehicle length detector;
a determination unit that determines that a vehicle length of the vehicle is equal to or greater than a threshold value when the second time after the offset is earlier than the first time;
Equipped with
the offset processing unit offsets the second time so as to delay the second time by a predetermined time when a distance from the entry detection position to the vehicle length determination position is shorter than the threshold value.
Vehicle length detector . A vehicle length detector for detecting the length of a vehicle traveling on a lane,
a first time acquisition unit that acquires a first time indicating a time when the vehicle has passed the lane entry detection position based on a vehicle detection signal indicating whether the vehicle is present at the lane entry detection position;
a second time acquisition unit that acquires a second time indicating a time when the vehicle reaches the vehicle length determination position based on a vehicle length detection signal indicating whether the vehicle is present at the vehicle length determination position downstream of the entry detection position in a vehicle traveling direction;
an offset processing unit that offsets the second time by an offset amount according to an installation environment of the vehicle length detector;
a determination unit that determines that a vehicle length of the vehicle is equal to or greater than a threshold value when the second time after the offset is earlier than the first time;
Equipped with
the offset processing unit offsets the second time so as to advance it by a predetermined time when a distance from the entry detection position to the vehicle length determination position is longer than the threshold value.
Vehicle length detector . A vehicle length detector for detecting the length of a vehicle traveling on a lane,
a first time acquisition unit that acquires a first time indicating a time when the vehicle passed the lane entry detection position based on a vehicle detection signal indicating whether the vehicle is present at the lane entry detection position;
a second time acquisition unit that acquires a second time indicating a time when the vehicle reaches the vehicle length determination position based on a vehicle length detection signal indicating whether the vehicle is present at the vehicle length determination position downstream of the entry detection position in a vehicle traveling direction;
an offset processing unit that offsets the second time by an offset amount according to an installation environment of the vehicle length detector;
a determination unit that determines that a vehicle length of the vehicle is equal to or greater than a threshold value when the second time after the offset is earlier than the first time;
Equipped with
the offset processing unit offsets the second time to be delayed by a predetermined time when the vehicle length detector is installed in the installation environment in which the vehicle having a load protruding in a front-rear direction of a vehicle body travels.
Vehicle length detector . The offset processing unit changes the offset amount in accordance with an assumed speed of the vehicle.
A vehicle length detector according to any one of claims 1 to 3 . The offset processing unit determines the assumed speed based on statistical information of speeds of a plurality of the vehicles traveling on the lane.
A vehicle length detector according to claim 4 . A vehicle length detection method for detecting the length of a vehicle traveling on a lane by a vehicle length detector, comprising:
acquiring a first time indicating a time when the vehicle has passed the lane entry detection position based on a vehicle detection signal indicating whether the vehicle is present at the lane entry detection position;
acquiring a second time indicating a time when the vehicle reaches the vehicle length determination position based on a vehicle length detection signal indicating whether the vehicle is present at a vehicle length determination position downstream of the entry detection position in a vehicle traveling direction;
offsetting the second time by an offset amount according to an installation environment of the vehicle length detector;
determining that a vehicle length of the vehicle is equal to or greater than a threshold value when the second time after the offset is earlier than the first time;
having
In the step of offsetting the second time, when a distance from the entry detection position to the vehicle length determination position is shorter than the threshold value, the second time is offset so as to be delayed by a predetermined time.
Vehicle length detection method. A vehicle length detector detects the length of a vehicle traveling in a lane.
acquiring a first time indicating a time when the vehicle has passed the lane entry detection position based on a vehicle detection signal indicating whether the vehicle is present at the lane entry detection position;
acquiring a second time indicating a time when the vehicle reaches the vehicle length determination position based on a vehicle length detection signal indicating whether the vehicle is present at a vehicle length determination position downstream of the entry detection position in a vehicle traveling direction;
offsetting the second time by an offset amount according to an installation environment of the vehicle length detector;
determining that a vehicle length of the vehicle is equal to or greater than a threshold value when the second time after the offset is earlier than the first time;
A program for executing
In the step of offsetting the second time, when a distance from the entry detection position to the vehicle length determination position is shorter than the threshold value, the second time is offset so as to be delayed by a predetermined time.
program .

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