JP2021124822A - Axle number detection device, toll collection system, axle number detection method, and program - Google Patents

Abstract

To provide an axle number detection device, a toll collection system, an axle number detection method, and a program that make it difficult to erroneously detect the number of axles of tires that touch the ground.SOLUTION: An axle number detection device 25 includes: an image acquisition unit 251 that acquires an image showing a side surface including at least tires of a vehicle; an area identifying unit 252 that identifies a tire area, which is an area where a tire is shown, in the image; a circular detection unit 253 that determines whether the tire area is circular; and a lift-up axle identifying unit 254 that identifies that an axle related to the tire area determined to be circular is lift up.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to an axle number detection device, a toll collection system, an axle number detection method, and a program.

In the toll collection system on a toll road, a method of determining a toll based on the vehicle type of a vehicle is known as a method of determining a toll. Vehicle type is determined by using various vehicle information such as the number of axles, vehicle length, vehicle height, license plate information, and presence / absence of towing.
For example, Patent Document 1 discloses a method of determining the number of axles of a traveling vehicle as vehicle information.

International Publication No. 2019/0664682

In Patent Document 1, in order to detect the number of axles of a vehicle having a lift axle mechanism, in a photographed image, the deflection of the road surface located directly below the lowest point of the tire is determined, and it is determined that the road surface is not bent. In addition, it is judged that it has been lifted up.
Therefore, when the road surface is hard to bend, it may be determined that the axles that have not been lifted up are lifted up, and the number of axles of the tires that come into contact with the ground may be erroneously detected.

The present disclosure has been made to solve the above problems, and provides an axle number detection device, a toll collection system, an axle number detection method, and a program that make it difficult to erroneously detect the number of axles of a tire that touches the ground. With the goal.

The present disclosure includes an image acquisition unit that acquires an image showing at least a side surface of a vehicle including a tire, a region identification unit that specifies a tire region that is a region in which the tire is projected in the image, and a tire region. This is an axle number detection device including a circular determination unit for determining whether or not a tire is circular, and a lift-up axis identification unit for specifying that the axle related to the tire region determined to be circular is lifted up. ..

The present disclosure includes a step of acquiring an image showing at least a side surface of a vehicle including a tire, a step of specifying a tire region which is a region in which the tire is projected in the image, and whether or not the tire region is circular. This is a method for detecting the number of axles, which includes a step of determining whether the tire is circular and a step of specifying that the axle related to the tire region determined to be circular is lifted up.

The present disclosure includes a step of acquiring an image showing at least a side surface of a vehicle including a tire on a computer of an axle number detecting device, and a step of specifying a tire region which is a region in which the tire is copied in the image. , A program for determining whether or not the tire region is circular, and a step for identifying that the axle related to the tire region determined to be circular is lifted up.

According to the axle number detection device, the toll collection system, the axle number detection method, and the program of the present disclosure, it is difficult to erroneously detect the number of axles of a tire that touches the ground.

It is the schematic perspective view of the toll collection system which concerns on 1st Embodiment of this disclosure. It is a block diagram of the axle number detection device which concerns on 1st Embodiment of this disclosure. It is a figure explaining the function of the image acquisition part which concerns on 1st Embodiment of this disclosure. It is a figure explaining the function of the circular determination part which concerns on 1st Embodiment of this disclosure. It is a side view of the vehicle which has the lift axle mechanism which concerns on 1st Embodiment of this disclosure. It is an enlarged view of the VI part of FIG. 5 when it is lifted up. It is an enlarged view of the VI part of FIG. 5 when it is not lifted up. It is a flowchart of the axle number detection method which concerns on 1st Embodiment of this disclosure. It is a figure explaining the function of the circular determination part which concerns on 2nd Embodiment of this disclosure. It is a figure explaining the function of the circular determination part which concerns on 3rd Embodiment of this disclosure. This is an example of the hardware configuration of the computer included in the axle number detection device according to each embodiment of the present disclosure.

Hereinafter, each embodiment of the present disclosure will be described with reference to the drawings. The same or corresponding configurations are designated by the same reference numerals in all drawings, and common description will be omitted.

<First Embodiment>
The axle number detection device according to the first embodiment will be described with reference to the drawings.

(Overall configuration of toll collection system)
The toll collection system 1 of the present embodiment is provided at the entrance tollhouse (or the exit tollhouse depending on the toll type) of the expressway, which is a toll road, and is related to the vehicle AA on which the user of the expressway rides. It is a system for collecting the amount of money that has been paid.

Vehicle AA is traveling in the lane LN leading from the general road side to the expressway side via the entrance tollhouse. Island ISs are laid on both sides of the lane LN, and at least a part of various devices constituting the toll collection system 1 is installed.
For example, vehicle AA may be a towing vehicle that includes a towing trailer.

Hereinafter, the direction in which the lane LN extends (± X direction in FIG. 1) is described as “lane direction”, and the expressway side (+ X direction side in FIG. 1) in the lane direction of the lane LN is described as “downstream”. .. Further, the general road side (-X direction side in FIG. 1) in the lane direction of the lane LN is described as "upstream".
Further, the width direction of the lane LN is referred to as the lane width direction (± Y direction in FIG. 1), and the vehicle height direction of the vehicle AA is referred to as the vertical direction (± Z direction in FIG. 1).

In the present embodiment, the toll collection system 1 performs billing processing by the wireless communication system.
The toll collection system 1 is a device that performs wireless communication processing (hereinafter, simply referred to as "wireless communication") with the vehicle AA that is about to pass through the entrance tollhouse, and performs billing processing related to the vehicle type of the vehicle AA. Is.
For example, the toll collection system 1 may be a part of a system for constructing an electronic toll collection system (ETC: Electronic Toll Collection System (registered trademark), also referred to as “automatic toll collection system”).

As shown in FIG. 1, the toll collection system 1 includes a vehicle detector 2, a communication antenna 3, and a vehicle type determination device 4.
For example, the charge collection system 1 further includes a charge processing unit (not shown) that controls a series of charge processing, and the acquired information, the determined charge amount information, and the like are not shown and are installed in a remote place via a communication line. It may be output to the central payment processing device (upper device).

(Communication antenna configuration)
The communication antenna 3 is installed above the lane LN.
The communication antenna 3 performs wireless communication processing with the vehicle-mounted device α of the vehicle AA. Specifically, the communication antenna 3 is formed so as to be able to transmit and receive electromagnetic waves of a predetermined frequency (for example, about 5.8 GHz), and wirelessly communicates with the on-board unit α mounted on the vehicle AA that arrives via the electromagnetic waves. Communicate.
For example, the communication antenna 3 may be provided downstream of the approach detection position XA.

(Configuration of vehicle type discrimination device)
The vehicle type discrimination device 4 is installed on the island IS.
For example, the vehicle type determination device 4 may acquire the vehicle length, vehicle height, number of shafts, shaft weight, license plate information, and the like of the vehicle AA that has entered the lane LN detected by various sensors of the toll collection system 1.
The vehicle type determination device 4 identifies the vehicle type classification of the vehicle AA that has entered the lane LN based on various information (vehicle length, vehicle height, number of axles, license plate information, etc.) obtained through various sensors.
For example, the vehicle type classification is divided into five categories: "light vehicle / motorcycle", "ordinary vehicle", "medium-sized vehicle", "large vehicle", and "extra-large vehicle".
For example, the toll collection system 1 may charge a charge according to the vehicle type classification of the vehicle AA from the vehicle type classification specified by the vehicle type determination device 4.

(Vehicle detector configuration)
The vehicle detector 2 is configured to be able to detect the vehicle AA at the approach detection position XA in the lane direction (± X direction).
The vehicle detector 2 includes a photographing device 22 and a processing unit 23.
For example, the vehicle detector 2 may further include a light emitting / receiving device 21.

(Configuration of imaging device)
The photographing device 22 photographs the side surface of the vehicle AA including at least the tire TR, and acquires the photographing data DT.
The photographing device 22 photographs from the roadside and acquires the photographing data DT.
For example, the photographing device 22 may be installed on the island IS.
Further, the photographing device 22 may be installed from the island IS toward the lane LN so that the vehicle AA passing through the approach detection position XA is reflected in the field of view.
Further, the photographing device 22 may be an area scan camera.
Further, the photographing device 22 may be provided adjacent to the light emitting / receiving device 21 downstream in the lane direction.

(Structure of light receiving and receiving device)
The light emitting / receiving device 21 is arranged at the approach detection position XA.
The photodetector 21 may output the photodetector signal DS depending on whether or not the projected light can be received.
The light emitting / receiving device 21 may be a transmissive type or a reflective type.
For example, the light emitting / receiving device 21 may receive / receive light in the vertical plane parallel to the lane width direction (in the plane perpendicular to the ± X direction) at the approach detection position XA over the entire vehicle height direction of the vehicle AA. good.
For example, as shown in FIG. 1, when the light emitting / receiving device 21 is a transmissive type, the light emitting / receiving device 21 is a light projecting device 21A that projects light across a lane LN and a light receiving device 21B that receives the light. May have a pair with. At that time, the projector 21 receives the light projected by the floodlight 21A when the vehicle AA does not exist at the approach detection position XA, and emits the light projected by the floodlight 21A when the vehicle AA exists at the approach detection position XA. Does not receive light.
Therefore, when the light emitting / receiving device 21 is a transmissive type, the photodetector signal DS indicates that the light is not received when the vehicle AA is present at the approach detection position XA.
When the light emitting / receiving device 21 is a reflection type, the photodetector signal DS indicates that the light is received when the vehicle AA is present at the approach detection position XA.

(Structure of processing unit)
The processing unit 23 processes, communicates, and the like various data in the vehicle detector 2.
As shown in FIG. 2, the processing unit 23 includes a detection unit 24 and an axle number detection device 25.
For example, the processing unit 23 may be installed on the island IS.
Further, the processing unit 23 may be provided downstream of the light emitting / receiving device 21 and the photographing device 22.

The detection unit 24 acquires the photodetector signal DS from the light emitting / receiving device 21.
The detection unit 24 detects whether or not the vehicle AA exists at the approach detection position XA based on the light detection signal DS of the light emitting / receiving device 21.
When the light emitting / receiving device 21 is a transmissive type, the detection unit 24 detects that the vehicle AA exists at the approach detection position XA when the light detection signal DS indicates that the light is not received.
When the light emitting / receiving device 21 is a reflection type, the detection unit 24 detects that the vehicle AA exists at the approach detection position XA when the light detection signal DS indicates that the light is received.

For example, when the detection unit 24 detects that the vehicle AA exists at the approach detection position XA, the detection unit 24 may notify the vehicle type determination device 4 that the vehicle AA has been detected.
Further, the detection unit 24 may continuously detect the presence of the vehicle AA from the time when the detection of the presence of the vehicle AA starts to the time when the detection of the presence of the vehicle AA ends as one vehicle.

(Configuration of axle number detection device)
The axle number detection device 25 processes and communicates various data for detecting the number of axles (number of axles).
The axle number detection device 25 functionally includes an image acquisition unit 251, an area identification unit 252, a circular determination unit 253, and a lift-up axis identification unit 254.
For example, the axle number detecting device 25 may further functionally include the axle number specifying unit 255.
Further, the axle number detection device 25 may notify the vehicle type determination device 4 of the detected number of axles of the vehicle AA.

The image acquisition unit 251 acquires an image IM showing at least a side surface of the vehicle AA including the tire TR.
The image acquisition unit 251 acquires an image IM based on the imaging data DT acquired from the imaging device 22.
For example, as shown in FIG. 3, the image acquisition unit 251 acquires four shooting data DTs shot in order at time T1, T2, T3, and T4, which are times at regular intervals, and shoots four shots in chronological order. The data DTs may be stitched together to generate an image IM of the entire vehicle AA.
In FIG. 3, four shooting data DTs are connected, but the number of the shooting data DTs to be joined may be three or less, or five or more.

As shown in FIG. 4, the area specifying unit 252 identifies the tire area RG1 which is the area in which the tire TR is copied in the image IM.

For example, the area specifying unit 252 may associate a plurality of tire regions RG1 specified (passing) with the vehicle AA while the detection unit 24 detects the vehicle AA as one vehicle.
Thus, for example, if the vehicle AA has four axle ASs, then four tire regions RG1 are identified for the vehicle AA.

For example, the area specifying unit 252 may specify the tire area RG1 from the color, shape, position, etc. in the image IM.
Further, the area specifying unit 252 may specify the in-tire region RG2, which is the region in which the wheel WH or hub HB of the vehicle AA is copied, from the color, shape, position, etc. in the image IM.

The circular determination unit 253 determines whether or not the tire region RG1 is circular.
For example, as shown in FIG. 4, the circular determination unit 253 may compare the tire region RG1 and the tire inner region RG2 to determine whether or not the tire region RG1 is circular.

For example, in determining whether or not the tire region RG1 is circular, the circular determination unit 253 determines whether or not the lower RG1L of the tire region RG1 and the lower RG2L of the tire inner region RG2 have a concentric relationship. You may. At that time, the circular determination unit 253 determines that it is circular if it has a concentric relationship, and determines that it is not circular if it does not have a concentric relationship.
At that time, the lower RG1L may be a predetermined range occupying the lower part of the entire tire region RG1. In the case shown in FIG. 4, the lower RG1L is a portion belonging to the tire region RG1 in the rectangular region surrounded by the dotted line.
Further, the lower RG2L may be a predetermined range occupying the lower part of the entire tire inner region RG2. In the case shown in FIG. 4, the lower RG2L is a portion of the rectangular region surrounded by the dotted line that belongs to the RG2 in the tire region.

For example, to determine whether or not there is a concentric relationship, the circles (or arcs) along the lower edge of each region of the lower RG1L and the lower RG2L are compared, and whether or not they are in a concentric relationship is determined. May be good.
For example, in the determination of whether or not there is a concentric relationship, the circle (or arc) that coincides with the lower end edge of the lower RG2L is used as a reference, and the circle (or arc) that has a concentric relationship with the reference circle is the lower part. It may be determined whether or not it matches the lower end edge of RG1L.
For example, in the determination of whether or not there is a concentric relationship, the circle (or arc) that coincides with the lower end edge of the lower RG2L is used as a reference, and the circle (or arc) that has a concentric relationship with the reference circle is the lower part. It may be determined whether or not it matches the lower end edge of RG1L.

It should be noted that the determination as to whether or not the relationship is concentric may be any determination as long as it is determined based on the comparison between the tire region RG1 and the tire inner region RG2.
As a modification, as a comparison between the tire region RG1 and the tire inner region RG2, the circular determination unit 253 may acquire the radius difference between the tire region RG1 and the tire inner region RG2.
At that time, as a determination of whether or not there is a concentric relationship, the circular determination unit 253 other than the radius difference in the lower portion between the tire region RG1 and the tire inner region RG2 and the lower portion between the tire region RG1 and the tire inner region RG2. It may be determined whether or not the radial difference (side portion, upper portion, etc.) matches, and whether or not the relationship is concentric.

The lift-up shaft specifying unit 254 identifies that the axle related to the tire region RG1 determined to be circular is lifted up.
Specifically, the lift-up shaft LUS is specified based on the following principle.

For example, as shown in FIG. 5, the vehicle AA is a vehicle having a lift axle mechanism, and of the four axle ASs of the vehicle AA, the first, second, and fourth axes from the front do not lift up. , It is assumed that the third axis from the front can be lifted up.

As shown in FIG. 6, when the third axle from the front is the lift-up axis LUS due to lift-up, the tire TR included in the third axle AS3 (lift-up axis LUS) of the third axle from the front is on the road surface. It is not in contact with the SL and has a circular shape similar to the wheel WH or hub HB.
In addition, the tire TR and the wheel WH or hub HB have a concentric relationship.

As shown in FIG. 7, when the tire TR is not lifted up, the tire TR included in the third axle AS3 is in contact with the road surface SL, so that a load is applied to the lower portion of the tire TR.
Therefore, the tire TR is deformed and does not become circular.
In addition, the tire TR and the wheel WH or hub HB do not have a concentric relationship.

Therefore, the lift-up shaft specifying unit 254 can specify the lift-up shaft LUS.
If it is determined that none of the tire regions RG1 of the plurality of tire regions RG1 specified for the vehicle AA is circular, the lift-up shaft specifying unit 254 specifies that there is no lift-up shaft LUS for the vehicle AA. You may.

The number of axles specifying unit 255 specifies the number of axles AS of the vehicle AA that have not been lifted up as the number of axles of the tire TR that comes into contact with the ground.
Here, the number of axles of the tire TR that touches the ground is the number of axle ASs including the tire TR that touches the ground among the axle ASs of the vehicle AA.
For example, the number of axles specifying unit 255 may specify the number of axles of the tire TR to be grounded as follows.

First, the axle number specifying unit 255 counts the number of a plurality of tire regions RG1 related to the vehicle AA as the number of axle ASs possessed by the vehicle AA.
Subsequently, the number of axles specifying unit 255 uses the number obtained by subtracting the number of lift-up shaft LUS specified by the lift-up shaft specifying unit 254 from the number of axle ASs possessed by the vehicle AA as the number of axles of the tire TR to be grounded. Identify.
For example, the number of axles specifying unit 255 may notify the number of axles of the specified tire TR to be grounded as the number of axles of the vehicle AA.

(motion)
The operation of the axle number detection device 25 will be described.
The operation of the axle number detection device 25 corresponds to the axle number detection method of the present embodiment.

First, as shown in FIG. 8, the image acquisition unit 251 acquires an image IM showing at least a side surface of the vehicle AA including the tire TR (ST01: image acquisition step).
Following the implementation of ST01, the area identification unit 252 identifies the tire area RG1 which is the area in which the tire TR is copied in the image IM (ST02: area identification step).
Following the implementation of ST02, the circular determination unit 253 determines whether or not the tire region RG1 is circular (ST03: circular determination step).
Following the implementation of ST03, the lift-up axis identification unit 254 identifies that the axle AS related to the tire region RG1 determined to be circular is lifted up (ST04: lift-up axis identification step).
Following the implementation of ST04, the axle number specifying unit 255 specifies the number of unlifted axle ASs of the vehicle AA as the number of axles of the tire TR to be grounded (ST05: axle number specifying step).

(Action and effect)
According to the present embodiment, the axle number detection device 25 determines whether or not the tire TR is deformed by image analysis.
The tire TR that is in contact with the road surface SL is deformed by the applied load at the lower portion that is in contact with the road surface SL.
On the other hand, the lifted tire TR does not deform because it is not in contact with the road surface SL and has a circular side surface shape.
Therefore, as described above, the axle number detection device 25 can identify the lift-up shaft LUS by determining whether or not the tire region RG1 is circular.
Therefore, the axle number detecting device 25 is unlikely to erroneously detect the number of axles of the tire TR that comes into contact with the ground.

Further, according to an example of the present embodiment, the axle number detecting device 25 determines whether or not the tire TR is deformed based on the wheel WH or the hub HB of the vehicle AA.
The wheel WH or hub HB of the vehicle AA maintains a circular shape with or without a load.
Therefore, as described above, by determining the deformation of the tire TR based on the wheel WH or the hub HB of the vehicle AA, the axle number detecting device 25 is unlikely to erroneously detect the number of axles of the tire TR that comes into contact with the ground.

Further, according to an example of the present embodiment, the circular determination unit 253 determines whether or not the lower RG1L of the tire region RG1 and the lower RG2L of the tire inner region RG2 have a concentric relationship.
The wheel WH or hub HB of the vehicle AA has a concentric relationship with the tire TR when no load is applied.
Therefore, as described above, by determining whether or not the relationship is concentric with respect to the wheel WH or hub HB of the vehicle AA, the axle number detecting device 25 erroneously determines the number of axles of the tire TR to be grounded. Hard to detect.

<Second embodiment>
The axle number detecting device 25 according to the second embodiment will be described with reference to the drawings.

The axle number detection device 25 of the second embodiment is configured and functions in the same manner as the axle number detection device 25 of the first embodiment except that an example of the function of the circular determination unit 253 is different. Is omitted.

Also in this embodiment, the circular determination unit 253 determines whether or not the tire region RG1 is circular.
For example, as shown in FIG. 9, the circular determination unit 253 compares the shape of the lower RG1L of the tire region RG1 with the shape of the non-grounded portion RG1B of the tire region RG1 and determines whether or not the tire region RG1 is circular. You may.
At that time, the lower RG1L may be a predetermined range occupying the lower part of the entire tire region RG1. In the case shown in FIG. 9, the lower RG1L is a portion belonging to the tire region RG1 in the rectangular region surrounded by the dotted line.
Further, the non-grounded portion RG1B may be a predetermined range occupying a side portion of the entire tire region RG1. In the case shown in FIG. 9, the non-grounded portion RG1B is a portion belonging to the tire region RG1 in the rectangular region surrounded by the dotted line.

For example, the circular determination unit 253 determines whether or not the shape of the lower RG1L of the tire region RG1 and the shape of the non-grounded portion RG1B of the tire region RG1 match, and determines whether or not the tire region RG1 is circular. good.
At that time, if the shape of the lower RG1L of the tire region RG1 and the shape of the non-grounded portion RG1B of the tire region RG1 match, it is determined that the tire region RG1 is circular.

According to an example of the present embodiment, the axle number detecting device 25 determines whether or not the tire TR is deformed based on the shape of the non-grounded portion RG1B of the vehicle AA.
In the non-grounded portion RG1B of the vehicle AA, no load is applied to the tire TR, so that the tire TR is not easily deformed.
Therefore, as described above, by using the shape of the non-grounded portion RG1B of the vehicle AA as a reference, the axle number detecting device 25 can easily determine whether the tire TR is circular.

In one example of the present embodiment, the non-grounded portion RG1B is a predetermined range that occupies a side portion of the entire tire region RG1, but is a predetermined range related to the region where the tire TR is not grounded with respect to the road surface SL. Any range may be used as long as it is available.
As a modification, the non-grounded portion RG1B may be a predetermined range that occupies the upper part of the entire tire region RG1 or may be a predetermined range that occupies the diagonally lower part (or diagonally upper part).

<Third Embodiment>
The axle number detecting device 25 according to the third embodiment will be described with reference to the drawings.

The axle number detection device 25 of the third embodiment is configured and functions in the same manner as the axle number detection device 25 of the first embodiment except that an example of the function of the circular determination unit 253 is different. Is omitted.

Also in this embodiment, the circular determination unit 253 determines whether or not the tire region RG1 is circular.
For example, as shown in FIG. 10, the region specifying unit 252 identifies a plurality of tire regions RG1 of the vehicle AA, and the circular determination unit 253 compares the shapes of the lower RG1L of the plurality of tire regions RG1 and the tire TR It may be determined whether it is circular or not.
At that time, the lower RG1L may be a predetermined range occupying the lower part of the entire tire region RG1. In the case shown in FIG. 10, the lower RG1L (RG11 to RG14) is a portion belonging to each tire region RG1 in the rectangular region surrounded by the dotted line.

For example, the area specifying unit 252 is a tire related to the axle provided in the rear based on the shape of the lower RG1L of the tire region RG1 related to the axle AS provided in the front among the plurality of axle ASs of the vehicle AA. It may be determined whether or not the shapes of the lower RG1L of the region RG1 match.
The reason for using the axle AS provided in the front as a reference is that the axle AS that is normally lifted up is not the axle AS provided in the front but the axle AS provided in the rear.
According to such an example, when the axle AS on the third axle from the front is lifted up as shown in FIG. 10, it is determined that the tire TR on the third axle from the front is circular.

For example, the area specifying unit 252 refers to the tire area RG1 related to the third axis from the front based on the shape of the lower RG11 of the tire area RG1 related to the first axis from the front among the four axle ASs of the vehicle AA. It may be determined whether or not the shapes of the lower RG 13 match. If the results of the determination do not match, it may be determined that the tire TR on the third axis from the front is not circular.
Further, the area specifying unit 252 refers to the tire area RG1 related to the fourth axis from the front based on the shape of the lower RG11 of the tire area RG1 related to the first axis from the front among the four axle ASs of the vehicle AA. It may be determined whether or not the shapes of the lower RG 14 match. If the results of the determination match, it may be determined that the tire TR on the fourth axis from the front is circular.

For example, the area specifying unit 252 refers to the lower RG13 of the tire area RG1 related to the third axis from the front with reference to the lower RG12 of the tire area RG1 related to the second axis from the front among the four axle ASs of the vehicle AA. It may be determined whether or not the shapes of are matched.
Further, the area specifying unit 252 refers to the lower RG14 of the tire area RG1 related to the fourth axis from the front with reference to the lower RG12 of the tire area RG1 related to the second axis from the front among the four axle ASs of the vehicle AA. It may be determined whether or not the shapes of are matched.

For example, the circular determination unit 253 may determine whether or not the tire TR is circular by comparing the shapes of the lower RG1L of the plurality of tire regions RG1 without determining the reference.
For example, the circular determination unit 253 determines whether or not the shape of the lower RG1L of the tire region RG1 to be determined is different from the shape of the lower RG1L of the other plurality of tire regions RG1, and determines whether or not the shape of the lower RG1L of the tire region RG1 to be determined is different from that of the lower RG1L of the tire region RG1 to be determined. May be determined whether or not is circular.

According to an example of the present embodiment, the axle number detecting device 25 determines whether or not the tire TR is deformed based on another tire TR.
In the vehicle AA having the lift-up shaft LUS, since no load is applied to at least one of the tires TR, there are a tire TR that is not deformed and a tire TR that is deformed.
Therefore, as described above, by comparing the shapes of the lower portions of the plurality of tire TRs, the axle number detection device 25 can easily determine whether the tire TRs are circular.

<Modification example>
In the example of each of the above-described embodiments, the case where the photographing device 22 is an area scan camera has been described, but any device may be used as long as it can photograph the vehicle AA passing through the approach detection position XA.
As a modification, the photographing device 22 may be a line scan camera.
At that time, the photographing device 22 may photograph the vicinity of the downstream side or the upstream side of the approach detection position XA, or may photograph the approach detection position XA.
However, when photographing the approach detection position XA, it is necessary to ground the line scan camera so that the installation position of the line scan camera and the installation position of the light emitting / receiving device 21 do not interfere with each other.
For example, at the approach detection position XA, a reflective light emitting / receiving device 21 may be provided on one road side and a line scan camera may be provided on the other road side so as not to interfere with each other.

In the example of each of the above-described embodiments, the image acquisition unit 251 generates an image IM by connecting a plurality of shooting data DTs shot in order in chronological order, but can acquire an image IM of the entire vehicle AA. Then, the image IM may be acquired in any mode.
As a modification, when the photographing device 22 is an area scan camera, the photographing device 22 may widen the field of view in the lane direction by a cylindrical lens, a concave cylindrical mirror, or the like, and take an image with the entire vehicle AA in the field of view. .. As a result, the image acquisition unit 251 may acquire the photographed data DT as it is as an image IM of the entire vehicle AA without connecting the photographed data DTs.
As another modification, when the photographing device 22 is a line scan camera, the image acquisition unit 251 arranges the photographing data DTs acquired from the photographing device 22 in chronological order from the beginning to the end of the vehicle AA. It may be acquired as an image IM of the entire AA.

In each of the above-described embodiments, the axle number detection device 25 is provided in the electronic toll collection system, but it may be provided in any system.
As a modification, the axle number detection device 25 may be provided in a system including an automatic toll collection machine.
As another modification, the axle number detection device 25 may be provided at a manned tollhouse where tolls are collected by a tollhouse.

In each of the above-described embodiments, the axle number detection device 25 is provided in the vehicle detector 2, but it may be provided in any mode.
As a modification, the axle number detection device 25 may be provided in the vehicle type determination device 4.
As another modification, the axle number detection device 25 may be a single device provided separately from the vehicle detector 2 and the vehicle type discrimination device 4.

In each of the above-described embodiments, the axle number detection device 25 is applied to the separate lane type toll collection system 1 installed in the island IS, but as a modification, the axle number detection device 25 is a free flow type. It may be applied to the toll collection system.

In each of the above-described embodiments, a program for realizing various functions of the axle number detection device 25 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is recorded in a computer system such as a microcomputer. It is supposed to perform various processes by reading it into the computer and executing it. Here, the processes of various processes of the CPU of the computer system are stored in a computer-readable recording medium in the form of a program, and the various processes are performed by the computer reading and executing this program. The computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Further, this computer program may be distributed to a computer via a communication line, and the computer receiving the distribution may execute the program.

In each of the above-described embodiments, an example of a computer hardware configuration for executing a program for realizing various functions of the axle number detection device 25 will be described.

As shown in FIG. 11, the computer 30 included in the axle number detection device 25 includes a CPU 31, a memory 32, a storage / playback device 33, an Input Output Interface (hereinafter, referred to as “IO I / F”) 34, and the computer 30. It includes a communication interface (hereinafter, referred to as "communication I / F") 35.

The memory 32 is a medium such as a Random Access Memory (hereinafter referred to as “RAM”) that temporarily stores data or the like used in a program executed by the axle number detecting device 25.
The storage / playback device 33 is a device for storing data or the like in an external medium such as a CD-ROM, a DVD, or a flash memory, or playing back data or the like on the external media.
The IO I / F 34 is an interface for inputting / outputting information and the like between the axle number detecting device 25 and another device.
The communication I / F35 is an interface for communicating with other devices via a communication line such as the Internet or a dedicated communication line.

<Other Embodiments>
Although some embodiments of the present disclosure have been described above, these embodiments are presented as examples and are not intended to limit the scope of the present disclosure. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the present disclosure. These embodiments and variations thereof are included in the scope and gist of the disclosure.

<Additional notes>
The axle number detection device, the toll collection system, the axle number detection method, and the program described in each embodiment are grasped as follows, for example.

(1) The axle number detection device 25 according to the first aspect has an image acquisition unit 251 that acquires an image IM showing a side surface including at least a tire TR of the vehicle AA, and the tire is copied in the image IM. A region specifying unit 252 that specifies the tire region RG1 that is a region, a circular determination unit 253 that determines whether the tire region RG1 is circular, and an axle AS related to the tire region RG1 that is determined to be circular. A lift-up shaft specifying portion 254 for identifying that the tire has been lifted up is provided.

According to this aspect, the axle number detecting device 25 determines whether or not the tire TR is deformed by image analysis.
The tire TR that is in contact with the road surface SL is deformed by the applied load at the lower portion that is in contact with the road surface SL.
On the other hand, the lifted tire TR does not deform because it is not in contact with the road surface SL and has a circular side surface shape.
Therefore, as described above, the axle number detection device 25 can identify the lift-up shaft LUS by determining whether or not the tire region RG1 is circular.
Therefore, the axle number detecting device 25 is unlikely to erroneously detect the number of axles of the tire TR that comes into contact with the ground.

(2) In the axle number detection device 25 according to the second aspect, in the tire, the circular determination unit 253 is a region in which the lower RG1L of the tire region RG1 and the wheel WH or hub HB of the vehicle AA are copied. The axle number detection device 25 of (1) determines whether or not the tire region RG1 is circular by comparing with the lower RG2L of the region RG2.

According to this aspect, the axle number detecting device 25 determines whether or not the tire TR is deformed based on the wheel WH or the hub HB of the vehicle AA.
The wheel WH or hub HB of the vehicle AA maintains a circular shape with or without a load.
Therefore, as described above, by determining the deformation of the tire TR based on the wheel WH or the hub HB of the vehicle AA, the axle number detecting device 25 is unlikely to erroneously detect the number of axles of the tire TR that comes into contact with the ground.

(3) In the axle number detecting device 25 according to the third aspect, the circular determination unit 253 compares the shape of the lower RG1L of the tire region RG1 with the shape of the non-grounded portion RG1B of the tire region RG1. The axle number detection device 25 of (1) for determining whether or not the tire region RG1 is circular.

According to this aspect, the axle number detecting device 25 determines whether or not the tire TR is deformed based on the non-grounded portion RG1B of the vehicle AA.
In the non-grounded portion RG1B of the vehicle AA, no load is applied to the tire TR, so that the tire TR is not easily deformed.
Therefore, as described above, by using the non-grounded portion RG1B of the vehicle AA as a reference, the axle number detecting device 25 can easily determine whether the tire TR is circular.

(4) In the axle number detecting device 25 according to the fourth aspect, the region specifying unit 252 identifies a plurality of the tire regions RG1 of the vehicle AA, and the circular determination unit 253 determines the plurality of the tire regions RG1. The axle number detection device 25 of (1) determines whether or not the tire TR is circular by comparing the shapes of the lower RG1L of the tire TR.

According to this aspect, the axle number detecting device 25 determines whether or not the tire TR is deformed based on the shape of the lower part of the other tire TR.
In the lift-up vehicle AA, at least one of the tires TR is not loaded. Therefore, the lift-up vehicle AA has a tire TR that is not deformed and a tire TR that is deformed. do.
Therefore, as described above, by comparing the shapes of the lower portions of the plurality of tire TRs, the axle number detection device 25 can easily determine whether the tire TRs are circular.

(5) The toll collection system 1 according to the fifth aspect includes the axle number detection device 25 according to any one of (1) to (4) and the photographing device 22 for capturing the image IM.

According to this aspect, the toll collection system 1 determines whether or not the tire TR is deformed by image analysis.
The tire TR that is in contact with the road surface SL is deformed by the applied load at the lower portion that is in contact with the road surface SL.
On the other hand, the lifted tire TR does not deform because it is not in contact with the road surface SL and has a circular side surface shape.
Therefore, as described above, the toll collection system 1 can specify the lift-up shaft LUS by determining whether or not the tire region RG1 is circular.
Therefore, the toll collection system 1 is unlikely to erroneously detect the number of axles of the tire TR that comes into contact with the ground.

(6) The method for detecting the number of axles according to the sixth aspect includes step ST01 for acquiring an image IM showing at least a side surface of the vehicle AA including the tire TR, and a region in which the tire TR is captured in the image IM. Step ST02 for specifying the tire region RG1, step ST03 for determining whether or not the tire region RG1 is circular, and the axle AS related to the tire region RG1 determined to be circular are lifted up. Includes step ST04 and.

According to this aspect, the axle number detection method determines whether or not the tire TR is deformed by image analysis.
The tire TR that is in contact with the road surface SL is deformed by the applied load at the lower portion that is in contact with the road surface SL.
On the other hand, the lifted tire TR does not deform because it is not in contact with the road surface SL and has a circular side surface shape.
Therefore, as described above, the lift-up shaft LUS can be specified by the axle number detection method by determining whether or not the tire region RG1 is circular.
Therefore, the method of detecting the number of axles is unlikely to erroneously detect the number of axles of the tire TR that comes into contact with the ground.

(7) The program according to the seventh aspect includes step ST01 for acquiring an image IM showing at least a side surface of the vehicle AA including the tire TR on the computer 30 of the axle number detection device 25, and the tire in the image IM. Step ST02 for identifying the tire region RG1 which is the region where the TR is copied, step ST03 for determining whether or not the tire region RG1 is circular, and the axle AS related to the tire region RG1 determined to be circular. Step ST04, which identifies that the tire is lifted up, is executed.

According to this aspect, the axle number detecting device 25 determines whether or not the tire TR is deformed by image analysis.
The tire TR that is in contact with the road surface SL is deformed by the applied load at the lower portion that is in contact with the road surface SL.
On the other hand, the lifted tire TR does not deform because it is not in contact with the road surface SL and has a circular side surface shape.
Therefore, as described above, the axle number detection device 25 can identify the lift-up shaft LUS by determining whether or not the tire region RG1 is circular.
Therefore, the axle number detecting device 25 is unlikely to erroneously detect the number of axles of the tire TR that comes into contact with the ground.

1 Toll collection system 2 Vehicle detector 3 Communication antenna 4 Vehicle type discriminator 21 Projector / receiver 21A Floodlight 21B Receiver 22 Imaging device 23 Processing unit 24 Detection unit 25 Axle number detection device 30 Computer 31 CPU
32 Memory 33 Storage / playback device 34 IO I / F
35 Communication I / F
251 Image acquisition unit 252 Area identification unit 253 Circular judgment unit 254 Lift-up axis specification unit 255 Number of axes specification unit AA Vehicle AS Axle AS3 Third axle DS Light detection signal DT Shooting data HB Hub IM Image IS Island LN Lane LUS Lift-up axis RG1 Tire area RG1B Non-grounded part RG1L Lower RG2 Tire inner area RG2L Lower RG11 Lower RG12 Lower RG13 Lower RG14 Lower SL Road surface T1 Time T2 Time T3 Time T4 Time TR Tire WH Wheel XA On-board unit α

Claims (7)

An image acquisition unit that acquires an image showing at least the side surface of the vehicle including the tires,
In the image, a region specifying portion that specifies a tire region, which is a region in which the tire is captured, and a region specifying portion.
A circular determination unit for determining whether or not the tire region is circular, and a circular determination unit.
A lift-up shaft specifying portion that specifies that the axle related to the tire region determined to be circular is lifted up, and
Axle number detection device equipped with. The first aspect of claim 1, wherein the circular determination unit compares the tire region with a region inside the tire, which is a region in which the wheel or hub of the vehicle is photographed, and determines whether or not the tire region is circular. Axle number detection device. The axle number detecting device according to claim 1, wherein the circular determination unit compares a lower portion of the tire region with a non-grounded portion of the tire region to determine whether or not the tire region is circular. The region specifying unit identifies a plurality of the tire regions of the vehicle.
The axle number detection device according to claim 1, wherein the circular determination unit compares the shapes of the lower portions of the plurality of tire regions to determine whether or not the tire is circular. The axle number detection device according to any one of claims 1 to 4.
An imaging device that captures the image and
A toll collection system equipped with. Steps to get an image showing at least the side of the vehicle that contains the tires,
In the image, the step of specifying the tire region, which is the region where the tire is captured, and
The step of determining whether or not the tire region is circular, and
A step of identifying that the axle associated with the tire area determined to be circular is lifted up,
Axle number detection method including. To the computer of the axle number detection device,
Steps to get an image showing at least the side of the vehicle that contains the tires,
In the image, the step of specifying the tire region, which is the region where the tire is captured, and
The step of determining whether or not the tire region is circular, and
A step of identifying that the axle associated with the tire area determined to be circular is lifted up,
A program that executes.

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