WO2016143854A1

WO2016143854A1 - Tire pattern assessment device, vehicle model determining device, tire pattern assessment method, and program

Info

Publication number: WO2016143854A1
Application number: PCT/JP2016/057589
Authority: WO
Inventors: 伸行尾張; 中山　博之; 重隆福▲崎▼; 健太中尾; 泰弘山口; 洋平小島
Original assignee: 三菱重工メカトロシステムズ株式会社
Priority date: 2015-03-11
Filing date: 2016-03-10
Publication date: 2016-09-15
Also published as: JP6446742B2; MY185928A; KR20170115087A; JP2016170508A; KR102022786B1

Abstract

A tire pattern assessment device is provided with: an image-capturing unit for connecting prescribed photographing areas, including at least the lower part of the body of a traveling vehicle, and capturing an image; an image-capturing control unit for controlling the image-capturing unit; and a tire assessment unit for assessing the number of consecutively connected tires of the vehicle on the basis of an image of the vehicle image-capture by the image-capture unit.

Description

Tire pattern determination device, vehicle type determination device, tire pattern determination method, and program

The present invention relates to a tire pattern determination device, a vehicle type determination device, a tire pattern determination method, and a program.
This application claims priority on March 11, 2015 based on Japanese Patent Application No. 2015-048427 filed in Japan, the contents of which are incorporated herein by reference.

Toll booths such as toll roads are equipped with toll collection facilities for collecting tolls. Such a fee collection facility includes an automatic fee collection device that performs fee collection processing with a user, and a vehicle type determination device that determines a vehicle type of a traveling vehicle. The automatic toll collector collects a fee according to the vehicle type determined by the vehicle type determination device.

In such a toll collection facility, for example, the vehicle type identification device disclosed in Patent Document 1 is a vehicle detector that obtains the height, length, etc. (shape pattern) of a traveling vehicle, and is stepped on by a tire of the vehicle. The vehicle type of the vehicle is determined based on various information obtained through the vehicle detector and the tread.
Further, the vehicle type identification device disclosed in Patent Document 2 generates a silhouette image of the entire vehicle from captured image data of the vehicle captured obliquely from the front, and the shape of the entire vehicle and the vehicle from the silhouette image. Tire pattern (whether double with two tires attached to one side of one axle or single with one tire attached to one side of one axle) Discriminating.

By the way, at a normal toll booth, the toll collector must determine the usage fee at the time of the toll collection process with the user, so the driver's seat of the vehicle reaches the toll collector. In the previous stage, the vehicle type discrimination result by the vehicle type discrimination device must be acquired.
Here, the number of axles of the vehicle can be acquired by detecting the number of times the tire of the vehicle has stepped on the treadle while the vehicle is passing. However, when the number of axles is used as one piece of information for identifying the vehicle type, all the tires of the target vehicle pass through the treadle before the driver's seat reaches the toll collector. Need to be. For this reason, in a normal toll booth, the maximum vehicle length (for example, 18 m) of a passing vehicle is taken into consideration so that the distance between the vehicle type identification device and the automatic toll collector is at least the maximum vehicle length or more. .

JP-A-8-235487 JP 2014-002534 A

However, for example, in a toll gate provided on a viaduct or the like, it may be difficult to embed treads on the road surface. In this case, it is not possible to install a vehicle type discriminating device using the tread as described above. For this reason, the vehicle type must be determined only by information such as the vehicle height and the length of the vehicle, but for vehicles with similar vehicle height and length, there is not enough information to determine the vehicle type, The vehicle type may not be correctly identified.
Even if the toll booth can embed treads, it may be difficult to secure the distance between the vehicle type discriminating device and the automatic toll collector beyond the maximum vehicle length due to the installation space of the toll booth. is there. In this case, for a vehicle having a vehicle length longer than the distance between the vehicle type identification device and the automatic toll collector, the driver's seat of the vehicle reaches the toll collector before all the tires pass through the tread. For this reason, the vehicle type determination device must determine the vehicle type before the acquisition of information such as the tire width, the number of axles, and the tread width is completed. Therefore, the vehicle type is determined for a vehicle with a long vehicle length. There is a possibility that the vehicle type is not correctly identified due to lack of information.
Thus, there is a possibility that the vehicle type cannot be correctly determined at a toll gate having a location condition where it is difficult to obtain information for determining the vehicle type from the tread.
Further, when generating the silhouette image of the entire vehicle from the captured image data of the vehicle as described above, the tire of the vehicle is disposed below the vehicle body of the vehicle and is therefore covered by the shadow of the vehicle body of the vehicle. End up. In addition, under the shooting environment such as at night, the entire captured image data becomes dark, and it may be difficult to distinguish the tire from the vehicle body and the shadow of the vehicle body. For this reason, it is difficult to acquire a tire pattern, which is information necessary for determining the vehicle type, and there is a possibility that the vehicle type cannot be correctly determined.

The present invention has been made in view of such problems, and can be installed regardless of the location conditions of the toll booth. The number of consecutive tires, which is one of the information necessary for discriminating the vehicle type, is determined. Provided are a tire pattern discriminating device, a vehicle type discriminating device, a tire pattern discriminating method, and a program that can be acquired without being affected by the shooting environment.

According to one aspect of the present invention, the tire pattern determination device includes a photographing unit (20A) that continuously photographs a predetermined photographing range including at least the lower part of the vehicle body of the traveling vehicle (A), and the predetermined photographing range. Based on vehicle detection information (D5, D10) indicating that the vehicle has entered the vehicle, an image (D7) photographed at a predetermined photographing timing by the photographing unit is extracted as a reference image (D7a), and the reference image An exposure condition setting unit (205) for setting an exposure condition with reference to the reference region (R) set in the vehicle, and a tire (T) of the vehicle based on the vehicle image captured by the imaging unit. A tire determination unit (204) for determining the number of continuous connections (D3). The photographing unit photographs the vehicle based on the exposure condition set in the exposure condition setting unit.

With such a configuration, the tire pattern determination device extracts, in the exposure condition setting unit, a vehicle image captured by the imaging unit at a predetermined imaging timing as a reference image, and the reference set in the reference image The exposure condition is set with reference to the area. The photographing unit photographs the vehicle based on the exposure condition. The tire determination unit determines the number of consecutive tires of the vehicle based on the image. The vehicle body refers to a part of the vehicle other than the tire. Further, the number of consecutive tires indicates the number of tires that are continuously provided at one attachment position of the vehicle (one attachment position on one axle).
Normally, when a vehicle is photographed, the tires of the vehicle enter the shadow of the vehicle body of the vehicle and are photographed in a low (dark) density value state. The “density value” of the photographed image is defined as being higher as it is brighter and lower as it is darker. For this reason, it is difficult to discriminate the tire of the vehicle from the vehicle body and the shadow of the vehicle body in the image of the vehicle photographed in such a dark state. However, according to the tire pattern determination device described above, the exposure condition setting unit sets the exposure condition based on the reference region, so that the imaging unit captures the vehicle tire that is normally captured in a dark state in a bright state. It becomes possible to do. Accordingly, the tire determination unit can detect the tire of the vehicle A based on the image captured by the imaging unit and determine the number of consecutive tires.
Further, the tire pattern determination device described above can determine the number of consecutive tires that is one piece of information necessary for determining the vehicle type. For this reason, there are restrictions on location conditions such as toll booths that cannot embed detection devices that detect information necessary for vehicle type identification on the road surface, or where sufficient space for installation cannot be secured, and sufficient information can be obtained from the detection devices. Even if there is no toll gate, it is possible to install a tire pattern determination device, and it is possible to perform vehicle type determination based on the number of consecutive tires determined by the tire pattern determination device.

According to an aspect of the present invention, the exposure condition setting unit sets a range including a lower part of a vehicle body of the vehicle as the reference region when the vehicle is photographed at the predetermined timing. The exposure conditions are set with reference to FIG.

With such a configuration, when the vehicle is photographed at the predetermined timing, the exposure condition setting unit sets a range including the lower part of the vehicle body of the vehicle as a reference region, and refers to the reference region. To set the exposure conditions.
The range including the lower part of the vehicle body is a range where the density value is lowest (darkens) when the vehicle is photographed. The exposure condition setting unit can set the exposure condition according to the range where the density value is lowest by referring to the reference area including the range. As a result, the photographing unit can photograph the vehicle tire with a detectable density value. Accordingly, the tire determination unit can detect the tire of the vehicle based on the image captured by the imaging unit and determine the number of consecutive tires.

According to an aspect of the present invention, the tire determination unit measures the tire diameter and the tire width of the vehicle based on the image, and determines the number of consecutive tires based on the tire diameter and the tire width. To do.

By setting it as such a structure, a tire determination part measures the tire diameter and tire width of a vehicle based on the image which the imaging | photography part image | photographed. The tire determination unit determines the number of consecutive tires based on the tire diameter and the tire width.
The tire width varies depending on the number of consecutive tires. For example, a tire width of “2” is about twice as large as that of a “1” tire. is doing. The tire determination unit can determine the number of consecutive tires based on the detected tire width by paying attention to the characteristics of the tire width.

According to one aspect of the present invention, the tire pattern determination device detects that the vehicle has entered the predetermined shooting range based on the image, and outputs the vehicle detection information (D10). 201).

With this configuration, the vehicle detection unit detects that the vehicle has entered the predetermined shooting range based on the image shot by the shooting unit, and outputs vehicle detection information. For this reason, even before the vehicle enters the toll gate, the vehicle detection unit can detect that the vehicle has entered the predetermined shooting range. Thereby, before the vehicle enters the toll gate, it is possible to set an exposure condition capable of detecting the tire of the vehicle and acquire an image photographed by the photographing unit based on the exposure condition. The tire pattern determination device can determine the number of consecutive tires based on the image thus captured. For this reason, even at a toll gate where there is not enough space to install a detection device for detecting information necessary for discriminating the vehicle type, the tire pattern determining device determines the tire determined before determining the vehicle usage fee. It becomes possible to perform vehicle type discrimination based on the number of continuous installations.

According to one aspect of the present invention, the tire pattern determination device further includes a vehicle detector (10A) that detects that the vehicle has entered the predetermined imaging range and outputs the vehicle detection information (D5). .

With this configuration, the vehicle detector detects that the vehicle has entered the predetermined shooting range and outputs vehicle detection information. Thereby, the imaging unit may perform imaging within a predetermined range after receiving the vehicle detection information, and it is not necessary to set the exposure condition by the exposure condition setting unit until the vehicle detection information is acquired. For this reason, the processing of the exposure condition setting unit and the control of the photographing unit can be simplified.

According to one aspect of the present invention, a vehicle type determination device is based on the tire pattern determination device according to any one of the above-described aspects and the number of consecutive tires of the vehicle determined by the tire pattern determination device. A vehicle type discriminating unit (10C) for discriminating the vehicle type.

According to one aspect of the present invention, there is provided a tire pattern determination method for determining the number of consecutive tires of a vehicle by using a photographing unit that continuously photographs a predetermined photographing range including at least a lower part of the vehicle body of the traveling vehicle. Based on vehicle detection information indicating that the vehicle has entered the predetermined shooting range, an image shot at a predetermined shooting timing by the shooting unit is extracted as a reference image and set in the reference image An exposure condition setting step for setting an exposure condition with reference to a reference area, a shooting step for shooting the vehicle based on the exposure condition set in the exposure condition setting step by the shooting unit, and the shooting unit And a tire determination step of determining the number of consecutive tires of the vehicle based on the image of the vehicle taken by the vehicle.

According to an aspect of the present invention, the program sets a computer of a tire pattern determination device including a photographing unit that continuously photographs a predetermined photographing range including at least a lower part of a vehicle of a traveling vehicle as the predetermined photographing range. Based on vehicle detection information indicating that the vehicle has entered, an image captured by the imaging unit at a predetermined imaging timing is extracted as a reference image, and a reference region set in the reference image is referred to. An exposure condition setting unit that sets an exposure condition, and a tire determination unit that determines the number of consecutive tires of the vehicle based on an image of the vehicle captured by the imaging unit. The vehicle is photographed based on the exposure condition set in the condition setting unit.

According to the tire pattern discriminating device, the vehicle type discriminating device, the tire pattern discriminating method and the program described above, the tire pattern discriminating apparatus, the tire pattern discriminating method, and the program can be installed regardless of the location conditions of the toll booth. The number of installations can be acquired without being affected by the shooting environment.

It is the schematic of the fee collection equipment which concerns on the 1st Embodiment of this invention. 1 is a schematic diagram of a vehicle type identification device according to a first embodiment of the present invention. 1 is a block diagram of a vehicle type identification device according to a first embodiment of the present invention. It is an example of the image image | photographed by the imaging | photography part which concerns on the 1st Embodiment of this invention. It is a figure which shows the example of the reference area of the image image | photographed by the imaging | photography part which concerns on the 1st Embodiment of this invention, and is the example which shows the reference area before exposure adjustment, and the example which shows the reference area after exposure adjustment. . It is a flowchart which shows the determination procedure of the tire pattern which concerns on the 1st Embodiment of this invention. It is a figure which shows the example of the hardware constitutions of a tire pattern determination apparatus.

<First Embodiment>
(overall structure)
Hereinafter, a fee collection facility 1 according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram of a toll collection facility 1 according to the first embodiment.
In this embodiment, the toll collection facility 1 is installed at a toll road exit toll gate as shown in FIG. 1, and collects a toll from the driver of the vehicle A who is a toll road user.

As shown in FIG. 1, the toll collection facility 1 in the present embodiment includes a vehicle type discriminating device 10, an automatic toll collection device 11, a start controller 13, and a start detector 14.
The toll collection facility 1 is a facility that is provided on the islands I arranged on both sides of the lane L and performs toll collection processing with the vehicle A stopped on the lane L.
In the following description, the direction along the lane L is referred to as the lane direction (X direction in FIG. 1). In addition, the direction in which the vehicle A travels on the lane L (the + X side in FIG. 1) is referred to as the rear side in the lane direction, and the side opposite to the direction in which the vehicle A travels (the −X side in FIG. 1) is the front side in the lane direction. Called. Further, a direction perpendicular to the lane direction of the lane L on the horizontal plane is referred to as a width direction (Y direction in FIG. 1), and a vehicle height direction (a direction perpendicular to the road surface) of the vehicle A is a height direction (FIG. 1). Z direction).

As shown in FIG. 1, the vehicle type discriminating apparatus 10 is provided on the front side in the lane direction (−X side in FIG. 1), detects the vehicle characteristics of the vehicle A entering the lane L of the toll gate, and detects the vehicle A This is a device group for discriminating the vehicle type division D1 (FIG. 3). In the present embodiment, the vehicle type identification device 10 includes a vehicle detector 10A, a license plate recognition unit 10B, and a tire pattern determination device 20.
Here, the vehicle type classification D1 of the vehicle A indicates a vehicle type for determining the toll for the toll road, and the vehicle type identification device 10 according to the present embodiment is, for example, “light vehicle etc.”, “ordinary vehicle” ”,“ Medium-sized vehicle ”,“ Large-sized vehicle ”, and“ Extra-large vehicle ”. The vehicle feature of the vehicle A is information unique to the vehicle A entering the lane L. In the present embodiment, the vehicle feature indicates information such as the license plate information of the vehicle A (vehicle registration information and the size of the license plate), the number of consecutive tires, and the like. Note that the number of consecutive tires indicates the number of tires provided continuously to one attachment position of the vehicle A (one-side attachment position on one axle). In the present embodiment, one tire T is attached at one attachment position (the number of consecutively connected is “1”), and two tires are attached at one attachment position. There is a double tire (the number of consecutive installations is “2”).
The vehicle type discrimination device 10 is a device that discriminates the vehicle type division D1 based on these vehicle characteristics. Note that specific configurations of the vehicle detector 10A, the license plate recognition unit 10B, and the tire pattern determination device 20 included in the vehicle type determination device 10 will be described later with reference to FIGS.

As shown in FIG. 1, the automatic toll collector 11 is provided on the far side in the lane direction (+ X side in FIG. 1) from the vehicle type discriminating device 10. The automatic toll collector 11 is provided on one side in the width direction of the lane L (−Y side in FIG. 1) in the present embodiment, but in the other embodiments, the other in the width direction of the lane L is provided. It may be provided on the side (+ Y side in FIG. 1).
The automatic toll collector 11 charges the driver of the vehicle A with a usage fee according to the vehicle type classification D1 of the vehicle A and the travel distance of the toll road.

The start controller 13 opens and closes the gate for the purpose of preventing the vehicle A from starting until the usage fee of the vehicle A entering the lane L is collected. As shown in FIG. 1, the start controller 13 is provided on the far side in the lane direction (+ X side in FIG. 1) with respect to the automatic toll collector 11 in the lane L. The start controller 13 opens the gate when the opening operation instruction signal is input from the automatic toll collector 11 and permits the vehicle A to start. Similarly, the start controller 13 closes the gate when a closing operation instruction signal is input from the automatic toll collector 11.

The start detector 14 is provided on the rear side in the lane direction (+ X side in FIG. 1) with respect to the start controller 13 in the lane L, and detects whether the vehicle A has left the lane L. The detection signal from the start detector 14 is output to the automatic toll collector 11. Upon receipt of the detection signal from the start detector 14, the automatic toll collector 11 determines whether there is a subsequent toll collection vehicle and sends a closing operation instruction signal to the start controller 13 to close the gate. Controls whether to output or keep the gate open.

(Configuration of vehicle type identification device)
Next, the configuration of the vehicle type identification device will be described with reference to FIGS.
FIG. 2 is a schematic diagram of the vehicle type identification device 10 according to the first exemplary embodiment of the present invention.
FIG. 3 is a block diagram of the vehicle type identification device 10 according to the first exemplary embodiment of the present invention.

As shown in FIG. 2, the vehicle type identification device 10 includes a vehicle detector 10 A, a license plate recognition unit 10 B, and a tire pattern determination device 20. The vehicle type determination device 10 further includes a vehicle type determination unit 10C for determining the vehicle type classification D1 of the vehicle A based on signals detected by these devices.
In the present embodiment, the vehicle type discriminating unit 10C is described as being built in the vehicle type discriminating apparatus 10 (for example, the vehicle detector 10A as shown in FIG. 2), but is not limited to this mode. For example, in another embodiment, the vehicle type determination unit 10C may be incorporated in a device other than the vehicle type determination device 10 connected on the network.

As shown in FIG. 2, the vehicle detector 10A is provided with a pair of light emitting and receiving light on both sides of the lane L on the lane direction front side (−X side in FIG. 2) of the automatic toll collector 11. 10 A of vehicle detectors output the detection signal according to the approach to the lane L of the vehicle A to the vehicle type discrimination | determination part 10C by the light receiving sensor not shown arranged in the height direction (Z direction in FIG. 2). 10 A of vehicle detectors output the detection signal which can detect the approach and passage for every vehicle A to the vehicle type discrimination | determination part 10C by intercepting the light with which the vehicle A which approached the lane L light-projected by a light reception sensor. . Specifically, as shown in FIG. 3, the vehicle detector 10A outputs a detection signal that can detect that the vehicle A has entered the lane L as vehicle entry information D5 (vehicle detection information) to the vehicle type determination unit 10C. Then, a detection signal that can detect that the vehicle A has passed the vehicle detector 10A is output to the vehicle type determination unit 10C as vehicle passage information D6.

As shown in FIG. 2, the license plate recognition unit 10B is provided on the far side in the lane direction (+ X direction in FIG. 2) from the vehicle detector 10A. The license plate recognition unit 10B captures a front image of the vehicle A including the license plate of the vehicle A in response to the detection of the vehicle A by the vehicle detector 10A, and the license plate information of the vehicle A (vehicle registration information and license plate) The size). As shown in FIG. 3, the license plate recognition unit 10B outputs the acquired license plate information to the vehicle type determination unit 10C as license plate information D2.

The tire pattern determination device 20 is a device that determines the continuous number D3 of the tires T of the vehicle A entering the lane L of the toll gate and outputs the continuous number D3 of the tires T to the vehicle type determination unit 10C. As illustrated in FIGS. 2 and 3, the tire pattern determination device 20 includes a photographing unit 20A, a main control unit 20B, and a storage unit 20C.

As shown in FIG. 2, the photographing unit 20A is provided on the island I on the opposite side of the lane L from the automatic toll collector 11. In the present embodiment, the photographing unit 20A is provided on the island I on the other side in the width direction of the lane L (the + Y side in FIG. 2), but depending on the arrangement of other devices in the toll collection facility 1, It may be provided on the island I on one side in the width direction (the −Y side in FIG. 2).

Further, the photographing unit 20A includes a lower part of the vehicle body of the vehicle A that is located on the near side in the lane direction (−X side in FIG. 2) than the vehicle detector 10A when the vehicle A is traveling on the road surface. The range is set as a predetermined shooting range. The photographing unit 20A is installed so that the predetermined photographing range can be photographed. Specifically, in the photographing unit 20A, the position in the height direction (Z direction in FIG. 2) is about 50% of the lowest ground height (the distance between the installation surface of the vehicle A and the lowermost portion of the central portion of the vehicle A). It is installed so that it becomes high. Further, the photographing unit 20A is installed so as to be inclined at about 45 degrees with respect to the lane direction and to face the front side in the lane direction (the −X side in FIG. 2).
As shown in FIG. 3, the photographing unit 20A outputs an image D7 obtained by continuously photographing a predetermined photographing range at a constant interval to the main control unit 20B.

The main control unit 20B determines the number D3 of consecutive tires T of the vehicle A based on the image D7 captured by the imaging unit 20A.
In the present embodiment, the main control unit 20B is described as being built in the tire pattern determination device 20 (for example, the photographing unit 20A as shown in FIG. 2), but is not limited to this mode. For example, in other embodiments, the main control unit 20B may be built in another device (for example, the vehicle detector 10A) of the vehicle type determination device 10 or other than the vehicle type determination device 10 connected on the network. It may be built in the device.

The storage unit 20C is a storage device for accumulating information for determining a tire pattern. In the present embodiment, the storage unit 20C is provided in the tire pattern determination device 20, but in other embodiments, the storage unit 20C may be provided in an external server or the like connected via a network.

The vehicle type determination unit 10C includes vehicle entry information D5 and vehicle passage information D6 acquired from the vehicle detector 10A, license plate information D2 acquired from the license plate recognition unit 10B, and a series of tires T determined by the tire pattern determination device 20. Based on the installation number D3, the vehicle type division D1 of the vehicle A is determined.

(Function of vehicle type identification device)
Next, functions of the vehicle type identification device 10 will be described with reference to FIGS.
FIG. 4 is an example of an image D7 photographed by the photographing unit 20A according to the first embodiment of the present invention.
FIG. 5 is a diagram illustrating an example of the reference region R of the image D7 photographed by the photographing unit 20A according to the first embodiment of the present invention, an example showing the reference region R before exposure adjustment, and after exposure adjustment. It is an example which shows the reference area | region R.

As shown in FIG. 3, the vehicle type determination device 10 includes a vehicle detector 10 A, a license plate recognition unit 10 B, a vehicle type determination unit 10 C, and a tire pattern determination device 20.
10 A of vehicle detectors are vehicle type discrimination | determination part 10C using the vehicle approach information D5 which can detect that the vehicle A approached the lane L, and the vehicle passage information D6 which can detect that the vehicle A passed 10 A of vehicle detectors. Output to.
Further, the license plate recognition unit 10B outputs the acquired license plate information D2 to the vehicle type determination unit 10C.

As shown in FIG. 3, the tire pattern determination device 20 includes an imaging unit 20A, a main control unit 20B, and a storage unit 20C.
The main control unit 20 B includes a vehicle detection unit 201, a shooting control unit 202, a tire detection unit 203, and a tire determination unit 204.

In the present embodiment, the photographing unit 20A outputs an image D7 obtained by continuously photographing a predetermined photographing range at a constant interval. The vehicle detection unit 201 determines whether or not the vehicle A is included for each of the plurality of images D7 received from the imaging unit 20A and captured at different times. For example, the vehicle detection unit 201 uses the known background subtraction method, interframe subtraction method, or the like to capture an image D7 taken at a certain time t and a time t-1 that is the past closest to the image D7. The difference from the image D7 is taken to detect the changed area. The vehicle detection unit 201 determines that the changed area is a moving object. Further, the vehicle detection unit 201 detects the moving amount (moving direction and speed) of the moving object by detecting in which area of the image D7 the moving object exists in the image D7 taken at each time. To detect. When a moving object having a predetermined movement amount (for example, a moving object moving from the front side in the lane direction toward the back side in the lane direction) is detected in the continuous image D7, the vehicle detection unit 201 detects that the moving object is the vehicle A It is judged that. Further, when a moving object having a movement amount different from the predetermined movement amount (for example, a moving object moving in the lane width direction) is detected in the continuous image D7, it is determined that the moving object is not the vehicle A.
The moving object detected by the vehicle detection unit 201 may be the vehicle body of the vehicle A, the tire T, the shadow of the vehicle body, or the like.

As shown in FIG. 4, the vehicle detection unit 201 determines whether or not the moving object determined to be the vehicle A is included in the reference region R of the image D7. The reference region R is a certain region of the image D7, and is a range including the lower part of the vehicle body of the vehicle A when the vehicle A enters a predetermined imaging range, for example.
When the vehicle detection unit 201 detects that the moving object determined to be the vehicle A is included in a certain region of the reference region R, as illustrated in FIG. 3, the imaging control unit 202 and the tire detection unit 203 are included. The vehicle detection information D10 is output.

Further, when the moving object is no longer detected in the reference region R of the image D7, the vehicle detecting unit 201 determines that the vehicle A has passed, and, as illustrated in FIG. 3, the vehicle detecting unit 201 proceeds to the photographing control unit 202 and the tire detecting unit 203. Vehicle exit information D11 is output.

Note that the vehicle detection unit 201 may determine that the moving object is the vehicle A when detecting that the same moving object is moving at a speed within a predetermined range. At this time, when the vehicle A is detected in the reference region R of the image D7, the vehicle detection unit 201 may output the vehicle detection information D10 to the shooting control unit 202 and the tire detection unit 203.
Moreover, in this embodiment, although the vehicle detection part 201 demonstrated the example using a background difference method and the interframe difference method, if the detection of the vehicle A is possible, you may use another method.

In the present embodiment, as shown in FIG. 4, a fixed range of a predetermined shooting range is set as the reference region R, but the present invention is not limited to this. For example, the reference area R may be set by an operation of an administrator or the like. In addition, when the vehicle detection unit 201 determines that the image D7 includes the vehicle A, a region below the vehicle A in the image D7 (the region having the lowest density value (darkest) among the regions determined to be the vehicle A) ) May be automatically determined, and a range including the lower side of the vehicle A may be set as the reference region R. In this case, the vehicle detection unit 201 outputs the vehicle detection information D10 and the vehicle exit information D11 depending on whether or not the vehicle A is included in the predetermined imaging range.

The imaging control unit 202 controls the imaging unit 20A. As shown in FIG. 3, the imaging control unit 202 has an exposure condition setting unit 205. In the present embodiment, the imaging control unit 202 outputs a command to the imaging unit 20A so as to perform imaging based on the exposure condition D4 set by the exposure condition setting unit 205. The exposure condition D4 indicates the aperture value and exposure time (shutter speed) of the photographing unit 20A. In the present embodiment, the exposure condition setting unit 205 sets two exposure conditions D4, ie, an exposure condition D4a for vehicle detection and an exposure condition D4b for tire detection, as the exposure condition D4. In addition, the photographing unit 20A performs first photographing that is photographed based on the exposure condition D4a for vehicle detection and second photographing that is photographed based on the exposure condition D4b for tire detection.

When the vehicle detection information D10 is not received from the vehicle detection unit 201 or when the vehicle exit information D11 is received from the vehicle detection unit 201, the exposure condition setting unit 205 sets the exposure condition D4a for vehicle detection.
The exposure condition setting unit 205 is configured to reduce the aperture according to the density value of the entire predetermined shooting range so that when the vehicle A enters the predetermined shooting range, an image that can clearly distinguish the vehicle A and the background can be shot. The value and the exposure time are set as the vehicle detection exposure condition D4a.
Specifically, the exposure condition setting unit 205 sets the vehicle detection exposure condition D4a as follows.

The exposure condition setting unit 205 generates a density histogram (a graph indicating the number of pixels having the same density value (appearance frequency) for each density value) at each time received from the imaging unit 20A, and the image D7. Measure the concentration value. The exposure condition setting unit 205 refers to the density histogram of the image D7 acquired at a time when the vehicle A does not exist in the predetermined shooting range, and determines whether or not the pixel number distribution is biased.

For example, when the number of pixels having a low (dark) density value is greater than a predetermined value, the exposure condition setting unit 205 determines that the density value of the image D7 is low and the exposure amount is insufficient. At this time, the exposure condition setting unit 205 calculates the exposure amount of the image D7 based on the exposure condition D4 when the image D7 is taken. The exposure condition setting unit 205 detects a vehicle with a smaller aperture value or a longer exposure time so that an image having a higher density value (brighter) than the image D7, that is, a larger exposure amount can be taken. Is set as the exposure condition D4a.
On the other hand, when the number of pixels having a high (bright) density value is larger than the predetermined value, it is determined that the density value of the image D7 is high and the exposure amount is excessive. At this time, the exposure condition setting unit 205 calculates the exposure amount of the image D7 based on the exposure condition D4 when the image D7 is taken. The exposure condition setting unit 205 uses a value obtained by increasing the aperture value or shortening the exposure time so that an image having a lower density value (darker) than the image D7, that is, an image with a small exposure amount can be captured. The exposure condition D4a for detection is set.
Note that the exposure condition setting unit 205 detects the vehicle detection exposure condition D4a so that an image having the same density value as that of the image D7, that is, an image having the same exposure amount can be taken when the deviation in the number of pixels is not detected. Set the same value as when D7 was shot.

As described above, the exposure condition setting unit 205 refers to the density value and the exposure amount of each image D7 acquired at a time when the vehicle A does not exist in the predetermined shooting range, so that the scene in the predetermined shooting range. An exposure condition D4a suitable for the above is set. As a result, even if the shooting environment such as weather, time, surrounding situation (such as shadows of buildings or lighting) is different, when the vehicle A enters the predetermined shooting range, an image D7 of the vehicle A is shot. This makes it easy to detect the vehicle A.
The imaging control unit 202 outputs the vehicle detection exposure condition D4a set by the exposure condition setting unit 205 to the imaging unit 20A. When receiving the exposure condition D4a, the imaging unit 20A captures a predetermined imaging range based on the exposure condition D4a from the next time.

Further, when the exposure condition setting unit 205 receives the vehicle detection information D10 from the vehicle detection unit 201, the exposure condition setting unit 205 sets the exposure condition D4b for tire detection.
The exposure condition setting unit 205 extracts an image D7 taken at the time when the vehicle detection unit 201 outputs the vehicle detection information D10 as a reference image D7a. The exposure condition setting unit 205 sets, as the tire detection exposure condition D4b, the aperture value and the exposure time according to the density value and the exposure amount of the reference region R of the image D7 taken after the reference image D7a. If the tire T of the vehicle A is included in the reference region R of the image D7, the tire detection exposure condition D4b may be set so that the tread pattern of the tire T can be detected. .
Specifically, the exposure condition setting unit 205 sets the exposure condition D4b for tire detection as follows.

The exposure condition setting unit 205 generates a density histogram of the reference area R of the reference image D7a and measures the density value of the reference area R, as shown in FIG. The horizontal axis of the density histogram indicates the density value, and the vertical axis indicates the number of pixels.

As shown in FIG. 5A, since the exposure condition D4a for vehicle detection is set as the exposure condition D4 at the timing when the reference image D7a is photographed, the vehicle body of the vehicle A included in the reference region R is set. Below, the density value is low (dark) due to the shadow of the vehicle body of the vehicle A, and the exposure amount is insufficient. For this reason, it is difficult to detect the boundary between the tire T of the vehicle A, the vehicle body of the vehicle A, and the shadow of the vehicle body. At this time, referring to the density histogram of the reference region R, the number of pixels having a low density value is large.

The exposure condition setting unit 205 detects a range of density values having a large number of pixels in the density histogram of the reference region R of the reference image D7a. In the present embodiment, the exposure condition setting unit 205 sets a range including the number of pixels corresponding to a predetermined ratio (for example, 20%) in the area of the vehicle A included in the reference region R to a density with a large number of pixels. Detect as a range of values. As shown in FIG. 5A, in the reference region R of the reference image D7a, a range of density values with a large number of pixels is biased in a region having a low density value.

Next, the exposure condition setting unit 205 calculates the exposure amount of the reference region R of the reference image D7a based on the exposure condition D4 when the reference image D7a is captured. The exposure condition setting unit 205 has a new density value higher (brighter) than the reference region R, that is, a larger exposure amount so that the imaging unit 20A can capture an image D7 that can detect the tire T of the vehicle A. A proper exposure amount is calculated. The exposure condition setting unit 205 sets a value obtained by reducing the aperture value or a value obtained by extending the exposure time as the tire detection exposure condition D4b so as to satisfy the new exposure amount.
Specifically, in the exposure condition setting unit 205, pixels included in an area having a low density value (for example, 0 to 20% of the entire density value range) in the density value range having a large number of pixels are shown in FIG. As shown in (b), a new exposure amount is calculated so as to be uniformly distributed in a range including a region having a density value higher than that region (for example, 0 to 50% of the entire density value range).
Note that the exposure condition setting unit 205 may adjust the aperture value and the exposure time in accordance with the position of the vehicle A, the amount of movement, and the like in the reference image D7a.

The imaging control unit 202 outputs the tire detection exposure condition D4b set by the exposure condition setting unit 205 in this way to the imaging unit 20A. When receiving the exposure condition D4b, the imaging unit 20A captures a predetermined imaging range based on the exposure condition D4b from the next time.
As shown in FIG. 5B, the reference region R of the image D7 photographed based on the tire detection exposure condition D4b is compared with the reference region R of the reference image D7a shown in FIG. The density value is high. Further, the density histogram of the reference region R of the image D7 shown in FIG. 5B appears at each density value as compared with the density histogram of the reference region R of the reference image D7a shown in FIG. The frequency is in a distributed state. For this reason, in the said image D7 image | photographed based on the said exposure condition D4b, it becomes possible to identify the vehicle body of the vehicle A and the tire T of the vehicle A, and to detect the tread pattern of the said tire T. .

The exposure condition setting unit 205 sets the tire detection exposure condition D4b suitable for the vehicle A every time the vehicle A is detected as described above. For this reason, even if the shooting environment such as the weather, time, and surrounding conditions (such as the shadow of the building and the presence of lighting) is different, the exposure condition D4b that can detect the tire T of the vehicle A is set according to the shooting environment. can do.

In the present embodiment, the example in which the exposure condition D4b for tire detection is set based on the reference image D7a has been described. However, the present invention is not limited to this. After setting the exposure condition D4b for tire detection, the exposure condition setting unit 205 generates a density histogram for the image D7 photographed based on the exposure condition D4b and measures the density value in the same manner as the reference image D7a. Then, the exposure amount of the image D7 may be calculated. The exposure condition setting unit 205 may set different tire detection exposure conditions D4b based on the density value and exposure amount of the image D7.

When the exposure condition setting unit 205 receives the vehicle exit information D11 from the vehicle detection unit 201 after setting the tire detection exposure condition D4b, the exposure condition setting unit 205 sets the vehicle detection exposure condition D4a as described above.

As shown in FIG. 3, the tire detection unit 203 receives the vehicle detection information D10 from the vehicle detection unit 201 and receives the vehicle exit information D11 until the images D7 received from the imaging unit 20A. It is determined whether or not the tire A of the vehicle A is included.

The tire detection unit 203 extracts edge portions by performing edge detection filter processing on each image D7. The texture is analyzed by calculating the periodicity and density of the boundary between the shades, and the longitudinal groove extending in the height direction of the vehicle A showing the tread pattern of the tire as shown in FIG. The texture of the tread pattern (tread pattern texture) detects a plurality of continuous areas (tread pattern areas) in the width direction of the vehicle and appears vertically on the side of the tire in a form adjacent to the tread pattern area. When an elliptical area (long in the vertical direction) is detected, it is determined that the part is the tire T of the vehicle A.
In the present embodiment, the tire detection unit 203 determines whether or not the tire T is included in each image D7 based on the presence or absence of the texture of the tread pattern of the tire. However, the present invention is not limited to this. In another embodiment, the tread pattern sample images D8 of a plurality of tires T acquired in advance as data for detecting the tire T in the storage unit 20C are accumulated, and the tire detection unit 203 uses the sample image D8. Then, it may be determined whether or not the tire T is included in the image D7 by comparing the reference region R of each image D7 received from the imaging unit 20A.
The tire detection unit 203 extracts the image D7 that is determined to include the tire T, and outputs the image D7 to the tire determination unit 204.

The tire determination unit 204 determines the number of consecutive tires D3 included in the image D7 received from the tire detection unit 203.
Double tires have two tires attached at one mounting position, so when comparing the tire widths of single tires and double tires with the same tire diameter, double tires are approximately twice the tire width of single tires. Tire width. The tire determination unit 204 pays attention to the difference in tire width between the single tire and the double tire, and based on the tire diameter and the tire width of the tire T included in the image D7, the tire T is a single tire or a double tire. Determine if there is. Specifically, the tire determination unit 204 determines the number of consecutive tires D3 as follows.

First, the tire determination unit 204 is based on the angle in the height direction of the photographing unit 20A and the length in the vertical direction of the vertically long elliptical area determined as the tire T included in the image D7 received from the tire detection unit 203. Calculate the tire diameter. Further, the tire width is detected from the length in the lateral direction (width direction) of the tread pattern region.
The storage unit 20C stores in advance tire information D9 in which a plurality of combinations of tire diameters and tire widths of commonly used tires are recorded. The tire determination unit 204 extracts tire information D9 having the same tire diameter as the tire T included in the image D7 from the tire information D9 stored in the storage unit 20C.
Next, the tire determination unit 204 compares the tire width of the tire T included in the image D7 with the tire width of each tire recorded in the extracted tire information D9.

When the tire width of the tire T included in the image D7 and the tire width of each tire recorded in the extracted tire information have the same value, the tire determination unit 204 is included in the image D7. It is determined that the tire T is a single tire.
On the other hand, when the tire width of the tire T included in the image D7 is a value that is significantly different from the tire width of each tire recorded in the extracted tire information (for example, the tire T included in the image D7) Tire width is a value about twice the tire width of each tire recorded in the extracted tire information), it is determined that the tire T included in the image D7 is a double tire.
Alternatively, since the tire on the first axis of the vehicle is a single tire regardless of the type of vehicle, the tire on the first axis is unconditionally determined as a single tire, and the tire width on the first axis is used as a reference. You may determine with the tire after the 2nd axis being a double tire by having the value of the tire width of the 1st axis being twice.
In the present embodiment, the example of determining whether the tire T is a single tire or a double tire from the tire width value of the tire T has been described, but the present invention is not limited to this. In the case of a double tire, the texture of the tread pattern is detected in two parts in the lateral direction (width direction) depending on the interval between the two tires. For this reason, the tire determination unit 204 determines that the tire is a double tire when two tread pattern textures are detected in the horizontal direction, and determines that a single tread pattern texture is detected when only one tread pattern texture is detected in the horizontal direction. You may make it determine with a tire.

When the tire determination unit 204 determines that the tire T included in the image D7 is a single tire, the tire determination unit 204 sets the consecutive number D3 of tires T to “1”. In addition, when the tire determination unit 204 determines that the tire T included in the image D7 is a double tire, the tire determination unit 204 sets the consecutive number D3 of tires T to “2”.
The tire determination unit 204 outputs the consecutive number D3 of tires T thus determined to the vehicle type determination unit 10C.

Next, the procedure of tire determination by the tire pattern determination device 20 will be described with reference to FIG.
FIG. 6 is a flowchart showing a tire pattern determination procedure according to the first embodiment of the present invention.

(Step ST101: Setting of exposure conditions for vehicle detection)
In the present embodiment, the photographing unit 20A photographs a predetermined photographing range at regular intervals.
The tire pattern determination device 20 sets the exposure condition D4a for vehicle detection in the exposure condition setting unit 205 of the imaging control unit 202 (step ST101). The exposure condition setting unit 205 is configured to reduce the aperture according to the density value of the entire predetermined shooting range so that when the vehicle A enters the predetermined shooting range, an image that can clearly distinguish the vehicle A and the background can be shot. The value and the exposure time are set as the vehicle detection exposure condition D4a.
The imaging control unit 202 outputs the vehicle detection exposure condition D4a to the imaging unit 20A. Thereafter, the imaging unit 20A captures a predetermined imaging range based on the vehicle detection exposure condition D4a.

(Step ST102: vehicle approach detection)
Next, the vehicle detection unit 201 determines whether or not the vehicle A has entered a predetermined shooting range (step ST102). For each of the plurality of images D7 received from the image capturing unit 20A, the vehicle detection unit 201 captures an image D7 captured at a certain time t and an image D7 captured at a time t-1 that is the closest to the image D7. Is taken to determine whether or not the vehicle A is included in the image D7.
When the vehicle detection unit 201 determines that the vehicle A is not included in the reference region R of the image D7 (step ST102: No), the vehicle detection unit 201 returns to the process of step ST101.
Further, when the vehicle detection unit 201 determines that the vehicle A is included in the reference region R of the image D7 (step ST102: Yes), the vehicle detection information D10 is output to the imaging control unit 202 and the tire detection unit 203. The process proceeds to the next step ST103.

(Step ST103: Measurement of density value of reference region)
Next, when the vehicle detection information D10 is received from the vehicle detection unit 201 (step ST102: Yes), the exposure condition setting unit 205 displays an image D7 taken at the time when the vehicle detection unit 201 outputs the vehicle detection information D10. Extracted as a reference image D7a. The exposure condition setting unit 205 generates a density histogram of the reference area R of the reference image D7a, and measures the density value of the reference area R (step ST103).
The exposure condition setting unit 205 detects a density value range having a large number of pixels in the density histogram of the reference region R of the reference image D7a. When there is a density value range with a large number of pixels in an area with a low density value, the exposure condition setting unit 205 determines that the reference area R has a low density value (dark), that is, an exposure amount is small.

(Step ST104: Calculation of exposure amount of reference area)
Next, the exposure condition setting unit 205 calculates the exposure amount of the reference region R of the reference image D7a based on the exposure condition D4 when the reference image D7a is captured. Since the exposure condition setting unit 205 determines that the reference region R has a low density value (dark), that is, an exposure amount is small, an image having a density value higher (bright) than the reference region R, that is, an exposure amount is large. A new exposure amount is calculated so that the image can be taken (step ST104).

(Step ST105: Setting of exposure conditions for tire detection)
Next, the exposure condition setting unit 205 sets, as the tire detection exposure condition D4b, a value obtained by reducing the aperture value or extending the exposure time so as to satisfy the new exposure amount calculated as described above. (Step ST105).
The imaging control unit 202 outputs the tire detection exposure condition D4b set by the exposure condition setting unit 205 in this way to the imaging unit 20A. When receiving the exposure condition D4b, the imaging unit 20A captures a predetermined imaging range based on the exposure condition D4b from the next time.

(Step ST106: tread pattern detection)
Next, the tire detection unit 203 analyzes each image D7 received from the imaging unit 20A during the period from the reception of the vehicle detection information D10 from the vehicle detection unit 201 to the reception of the vehicle exit information D11. Whether or not the texture (tread pattern texture) of the vertical groove extending in the height direction of the vehicle A indicating the tread pattern of the tire T includes a continuous region (tread pattern region) in the vehicle width direction. Is determined (step ST106). If the tread pattern area is not detected, the tire detection unit 203 determines that the tire D of the vehicle A is not included in the image D7 (step ST106: No), and returns to step ST106 again to return to the next image. D7 is analyzed. On the other hand, when the tire detection unit 203 detects the tread pattern region, the tire detection unit 203 determines that the tire D of the vehicle A is included in the image D7 (step ST106: Yes). At this time, the image D7 is output to the tire determination unit 204, and the process proceeds to the next step ST107.

(Step ST107: detection of tire diameter and tire width)
Next, the tire determination unit 204 detects the tire diameter and the tire width of the tire T included in the image D7 received from the tire detection unit 203 (step ST107).

(Step ST108: Determination of the number of consecutive tires)
Next, the tire determination unit 204 compares the tire width of the tire T included in the image D7 with the tire width of each tire recorded in the extracted tire information D9, and the consecutive number D3 of the tire T is compared. Is determined (step ST108).
When the tire width of the tire T included in the image D7 and the tire width of each tire recorded in the extracted tire information have the same value, the tire determination unit 204 is included in the image D7. It is determined that the tire T is a single tire.
On the other hand, when the tire width of the tire T included in the image D7 is significantly different from the tire width of each tire recorded in the extracted tire information (for example, included in the image D7). When the tire width of the tire T is a value about twice the tire width of each tire recorded in the tire information), it is determined that the tire T included in the image D7 is a double tire.
The tire determination unit 204 outputs the determined continuous number D3 of tires T to the vehicle type determination unit 10C.

(Step ST109: Vehicle passage detection)
Next, the vehicle detection unit 201 determines whether or not the vehicle A has passed a predetermined imaging range (step ST109).
When the vehicle detection unit 201 detects the vehicle A in the reference region R of the image D7, the vehicle detection unit 201 determines that the vehicle A is in the predetermined shooting range (step ST109: No), and returns to the process of step ST106. . On the other hand, when the vehicle detection unit 201 does not detect a low density region (dark portion) such as a shadow or a tire T caused by the vehicle A in the reference region R of the image D7, the vehicle A determines that the vehicle A has passed a predetermined shooting range ( Step ST109: Yes). In addition, when the exposure condition D4b for tire detection is set, when the vehicle A passes, overexposure may occur and halation may occur. For this reason, the vehicle detection part 201 may judge that the vehicle A passed the predetermined imaging | photography range, when a halation is detected in the whole acquired image D7. The vehicle detection unit 201 outputs vehicle exit information D11 to the imaging control unit 202 and the tire detection unit 203.

(Hardware configuration)
Moreover, the example of the hardware constitutions of the tire pattern determination apparatus 20 in each above-mentioned embodiment is demonstrated.
FIG. 7 is a diagram illustrating an example of a hardware configuration of the tire pattern determination device 20.
As shown in FIG. 7, the tire pattern determination device 20 includes a memory 810, a storage / reproduction device 820, an IO I / F (Input Output Interface) 830, an external device I / F (Interface) 840, and a communication I. / F (Interface) 850, CPU (Central Processing Unit) 860, and auxiliary storage device 870 are provided.

The memory 810 is a medium such as a RAM (Random Access Memory) that temporarily stores data used in the program of the tire pattern determination device 20.
The storage / reproduction device 820 is a device for storing data in an external medium such as a CD-ROM, a DVD, a flash memory, etc., and reproducing data in the external medium.
The IO I / F 830 is an interface for inputting and outputting information and the like with each device of the vehicle type identification device 10.
The external device I / F 840 is an interface for performing control of devices provided in the tire pattern determination device 20 and transmission / reception of information and the like. In the tire pattern determination device 20 of the above-described embodiment, the external device I / F 840 performs control of the imaging unit 20A and transmission / reception of information and signals.
The communication I / F 850 is an interface for the tire pattern determination device 20 to communicate with an external server via a communication line such as the Internet.
CPU 860 executes a program and controls to execute each function of tire pattern determination device 20. In the above-described embodiment, the tire pattern determination device 20 performs control so as to determine the consecutive number D3 of tires T.
The auxiliary storage device 870 is for recording a program executed by the CPU 860, data used when the program is executed, and generated data. The auxiliary storage device 870 is an HDD (Hard Disk Drive), a flash memory, or the like.

The program of the tire pattern determination device 20 may be recorded on an external medium such as a CD-ROM, a DVD, or a flash memory. In this case, the storage / playback device 820 writes (stores) and reads (stores) Play). You may read the program memorize | stored in the external server from communication I / F850.
A program stored in an external medium or an external server may be stored in the auxiliary storage device 870.

The CPU 860 functions as the vehicle detection unit 201, the imaging control unit 202, the tire detection unit 203, the tire determination unit 204, and the exposure condition setting unit 205 of the tire pattern determination device 20 by executing the above program. When the CPU 860 performs various processes, the data generated by each process is stored in the auxiliary storage device 870.

(Function and effect)
According to the tire pattern determination device 20 described above, the exposure condition setting unit 205 measures the density value of the reference region R of the reference image D7a and calculates the exposure amount. The exposure condition setting unit 205 also exposes tire detection exposure conditions so that the photographing unit 20A can photograph an image D7 that can detect the tire T of the vehicle A based on the density value and the exposure amount of the reference region R. D4b is set. When receiving the tire detection exposure condition D4b, the imaging unit 20A captures a predetermined imaging range based on the tire detection exposure condition D4b from the next time.
Normally, when the vehicle A is photographed, the tire T of the vehicle A is photographed in a dark state due to the vehicle body of the vehicle A and the shadow of the vehicle body. For this reason, it is difficult to identify the tire T of the vehicle A and the vehicle body of the vehicle A or the shadow of the vehicle body in the image of the vehicle A photographed in such a dark state. However, as described above, when the exposure condition setting unit 205 sets the exposure condition D4b for tire detection, the photographing unit 20A photographs the tire T of the vehicle A that is usually photographed in a dark state in a bright state. It becomes possible. For this reason, the tire determination unit 204 can detect the tire of the vehicle A based on the image D7 photographed by the photographing unit 20A based on the exposure condition D4b for tire detection.
Further, every time the vehicle detection unit 201 detects that the vehicle A has entered the predetermined imaging range, the imaging unit measures the density value and calculates the exposure amount based on the reference image D7a obtained by imaging the vehicle A. Therefore, the exposure condition D4b that can detect the tire T of the vehicle A can be set even if the shooting environment such as the weather, time, and the surrounding situation (such as the shadow of the building and the presence or absence of lighting) is different.

Also, for example, in a vehicle type identification device using a tread board, if the distance between the vehicle type identification device and the automatic toll collector cannot be secured more than the maximum vehicle length, the vehicle tires before the driver's seat reaches the automatic toll collector. May not be able to pass through the tread, and the number of axes of the vehicle may not be determined. However, according to the tire pattern determination device 20 described above, for each axle detected by the tire determination unit 204, the continuous number D3 of tires T, which is one piece of information necessary for determining the vehicle type division D1, is determined. Can do. For this reason, even in a state where the number of axles of the vehicle A cannot be acquired, the vehicle type is determined based on the continuous number D3 of the tire T or based on the continuous number D3 of the tire T and the license plate information D2. The classification D1 can be determined. For this reason, there are restrictions on location conditions such as toll booths that cannot embed a detection device for detecting information necessary for discrimination of the vehicle type division D1 on the road surface or a sufficient space for installation, and there is sufficient information from the detection device Even at a toll booth that cannot be obtained, the tire pattern determination device 20 can be installed, and the vehicle type can be determined based on the consecutive number D3 of tires T determined by the tire pattern determination device 20. It becomes.

Further, according to the tire pattern determination device 20 described above, the reference region R of the image D7 is a range including the lower side of the vehicle body of the vehicle A.
The range including the lower part of the vehicle body of the vehicle A is a range where the density value is lowest (darker) when the vehicle A is photographed. The exposure condition setting unit 205 can detect the tire tread pattern even in a range including the lower part of the vehicle body of the vehicle A having the lowest density value by referring to the reference region R set in this way. It is possible to calculate an exposure amount such that an image is captured with a proper density value, and to set an exposure condition D4 that satisfies the exposure amount. Accordingly, the tire detection unit 203 can detect the presence or absence of a tread pattern based on the image D7 and determine whether or not the tire T is included in the image D7.

Moreover, according to the tire pattern determination device 20 described above, the tire determination unit 204 measures the tire diameter and the tire width of the vehicle based on the image D7 captured by the imaging unit.
The tire determination unit 204 pays attention to the feature that the tire width of the double tire has a tire width that is approximately twice the tire width of the single tire, and determines the tire diameter and the tire width of the tire T included in the image D7. Based on this, it can be determined whether the tire T is a single tire or a double tire.

Further, according to the tire pattern determination device 20 described above, the vehicle detection unit 201 detects that the vehicle A has entered a predetermined imaging range based on the image D7 captured by the imaging unit 20A, and uses the vehicle detection information D10. Output.
An image D7 photographed at the time when the vehicle A enters a predetermined photographing range is photographed with the exposure condition D4a for vehicle detection set by the exposure condition setting unit 205. For this reason, the vehicle detection part 201 can detect easily that the vehicle A entered into the predetermined imaging | photography range based on the said image D7.
For this reason, even before the vehicle A enters the toll gate, the vehicle detection unit 201 can detect that the vehicle A has entered the predetermined shooting range. Thereby, before the vehicle A enters the toll gate, the exposure condition D4b capable of detecting the tire T of the vehicle A is set, and the image D7 captured by the imaging unit 20A is acquired based on the exposure condition D4b. Can do.
The tire determination unit 204 can determine the number of consecutive tires based on the image D7 taken in this way. For this reason, the vehicle type discriminating unit 10C can determine the usage fee of the vehicle A even if it is a toll booth where a space for installing a detection device for detecting information necessary for discriminating the vehicle type division D1 cannot be secured. Based on the number of consecutive tires D3 determined by the tire determination unit 204, the vehicle type division D1 can be determined.

As mentioned above, although embodiment of this invention was described in detail, unless it deviates from the technical idea of this invention, it is not limited to these, A some design change etc. are possible.
For example, in the above-described embodiment, the example in which the vehicle type identification device 10 includes the vehicle detector 10A has been described. However, the vehicle detector 10A may be omitted, and the installation space and the installation cost of the vehicle type identification device 10 are reduced accordingly. Can be reduced. Even in this case, the vehicle detection unit 201 of the tire pattern determination device 20 can detect entry and passage of the vehicle.

Moreover, although the vehicle detection part 201 demonstrated the example which detects the approach and passage of the vehicle A in the above-mentioned embodiment, it is not restricted to this. The tire pattern determination device 20 receives the vehicle entry information D5 and the vehicle passage information D6 from the vehicle detector 10A, and sets the exposure condition D4 based on the vehicle entry information D5 and the vehicle passage information D6. Also good. In this case, the photographing unit 20A may photograph a predetermined photographing range only during a period from when the vehicle entry information D5 is received until the vehicle passage information D6 is received, and until the vehicle entry information D5 is acquired. The setting of the exposure condition D4 by the exposure condition setting unit 205 becomes unnecessary. For this reason, the processing of the exposure condition setting unit 205 and the control of the photographing unit 20A by the photographing control unit 202 can be simplified. Further, the vehicle detection unit 201 may be omitted.
Even with such a configuration, it is possible to obtain the same effects as those of the above-described embodiment.

Further, in the above-described embodiment, an example in which the tire pattern determination device 20 includes one photographing unit 20A has been described, but the present invention is not limited to this. The tire pattern determination device 20 may include two imaging units, an imaging unit for imaging the reference image D7a used for setting the exposure conditions, and an imaging unit for imaging the image D7 used for tire determination. Good.
Even with such a configuration, it is possible to obtain the same effects as those of the above-described embodiment.

In the above-described embodiment, the example in which the vehicle type identification device 10 does not include the tread has been described, but the present invention is not limited to this. In a toll booth where a tread can be embedded on the road surface, the vehicle type identification device 10 may further include a tread. By acquiring information such as the number of axles from the tread board, it is possible to determine the vehicle type in consideration of the information.

DESCRIPTION OF SYMBOLS 1 Toll collection equipment 10 Vehicle type discrimination device 10A Vehicle detector 10B License plate recognition unit 10C Vehicle type discrimination unit 11 Automatic toll collection device 13 Start control device 14 Start detector 20 Tire pattern determination device 20A Imaging unit 20B Main control unit 20C Storage unit 201 Vehicle detection unit 202 Imaging control unit 203 Tire detection unit 204 Tire determination unit 205 Exposure condition setting unit A Vehicle I Island L Lane R Reference area T Tire

Claims

An imaging unit for continuously imaging a predetermined imaging range including at least the lower part of the vehicle body of the traveling vehicle;
Based on vehicle detection information indicating that the vehicle has entered the predetermined shooting range, an image shot at a predetermined shooting timing by the shooting unit is extracted as a reference image, and the reference set in the reference image An exposure condition setting unit for setting an exposure condition with reference to the area;
A tire determination unit that determines the number of consecutive tires of the vehicle based on the vehicle image captured by the imaging unit;
The photographing unit photographs the vehicle based on the exposure condition set in the exposure condition setting unit.
Tire pattern determination device.
The exposure condition setting unit sets a range including a lower part of a vehicle body of the vehicle as the reference area when the vehicle is photographed at the predetermined timing, and sets the exposure condition with reference to the reference area. To
The tire pattern determination apparatus according to claim 1.
The tire determination unit measures the tire diameter and tire width of the vehicle based on the image, and determines the number of consecutive tires based on the tire diameter and tire width.
The tire pattern determination apparatus according to claim 1 or 2.
A vehicle detection unit that detects that the vehicle has entered the predetermined imaging range based on the image and outputs the vehicle detection information;
The tire pattern determination apparatus according to any one of claims 1 to 3.
A vehicle detector for detecting that the vehicle has entered the predetermined shooting range and outputting the vehicle detection information;
The tire pattern determination apparatus according to any one of claims 1 to 3.
The tire pattern determination device according to any one of claims 1 to 5,
A vehicle type discriminating unit for discriminating a vehicle type based on the number of consecutive tires of the vehicle determined by the tire pattern determining device;
A vehicle type discrimination device comprising:
A tire pattern determination method for determining the number of consecutive tires of a vehicle using an imaging unit that continuously captures a predetermined imaging range including at least a lower part of a vehicle body of a traveling vehicle,
Based on vehicle detection information indicating that the vehicle has entered the predetermined shooting range, an image shot at a predetermined shooting timing by the shooting unit is extracted as a reference image, and the reference set in the reference image An exposure condition setting step for setting an exposure condition with reference to an area; and
A photographing step of photographing the vehicle based on the exposure condition set in the exposure condition setting step by the photographing unit;
A tire determination step of determining the number of consecutive tires of the vehicle based on the image of the vehicle captured by the imaging unit.
Tire pattern determination method.
A computer of a tire pattern determination device including a photographing unit that continuously photographs a predetermined photographing range including at least a lower part of a vehicle body of a traveling vehicle,
Based on vehicle detection information indicating that the vehicle has entered the predetermined shooting range, an image shot at a predetermined shooting timing by the shooting unit is extracted as a reference image, and the reference set in the reference image An exposure condition setting unit that sets an exposure condition with reference to an area,
A tire determination unit that determines the number of consecutive tires of the vehicle based on the image of the vehicle captured by the imaging unit;
A program that functions as
The photographing unit photographs the vehicle based on the exposure condition set in the exposure condition setting unit.
program.