JP7019444B2 - How to identify winter tires - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act Announced at the 25th Business Improvement and Reform Presentation in 2017 hosted by West Japan Highway Engineering Shikoku Co., Ltd. held at Takamatsu International Hotel on August 19, 2017.

Application of Article 30, Paragraph 2 of the Patent Act Announced at the 32nd Nippon Road Conference hosted by the Japan Road Association held at Toshi Center Hotel on October 31, 2017.

Application of Article 30, Paragraph 2 of the Patent Law Announced at the Highway Techno Fair 2017 sponsored by the Highway Research Association held at Tokyo Big Sight (Tokyo International Exhibition Center) East Hall 7.8 on November 21, 2017.

The present invention relates to a method for determining whether or not a tire of an automobile or the like is a winter tire.

Generally, in winter, winter tire regulations are enforced in response to the occurrence of snowfall and road surface freezing.
If this winter tire regulation is made, vehicles without all-wheel winter tires or drive wheel chains will not be allowed to pass.

For example, on highways, toll roads, and motorways, when winter tire regulations are enforced, confirmation personnel on the road manager side stop the vehicles at the entrances of those roads, and visually check each vehicle one by one. Sometimes I check the tires.

As a method for discriminating the winter tire, the applicant of the present application has proposed Japanese Patent Application No. 2016-173834.
In this prior art, a degree of polarization image is generated using a photographing device that acquires reflected light information of different polarization direction components, that is, a modified camera, and a histogram is generated from the reflection information contained in the obtained degree of polarization image. However, it is determined whether or not the tire is a winter tire according to the degree of dispersion of the histogram.

In this conventional technique, by using a polarized camera, it is possible to efficiently discriminate winter tires.
On the other hand, since the polarized camera is expensive, the system adopting the conventional technology has a problem that the introduction cost is high.

In addition, since the polarized camera has low sensitivity, if the speed of a vehicle or the like equipped with tires to be discriminated is high, subject blurring is likely to occur in the acquired image, which may be one of the factors that hinder proper discrimination. ..

Japanese Patent Application No. 2016-173834

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make it possible to reliably discriminate winter tires regardless of day or night by using low-cost equipment.

In order to achieve the above object, the method for discriminating a winter tire according to the present invention is as follows.
An irradiation step of diagonally irradiating a tread surface of a vehicle tire passing through a predetermined driving path with a light beam from outside the tire passing region.
The tread surface of the tire irradiated with light rays in the irradiation step is photographed with a high-sensitivity photographing device from the opposite side of the passing area of the tire with the light rays of the irradiation step, and a photographing step of generating a visible image.
A brightness image (monochrome visible image) is generated from the visible image obtained in the shooting step, the generated brightness image is smoothed to generate a smoothed image (brightness distribution image), and a smoothed image is obtained from the brightness image. An image processing step that makes a difference, removes unevenness, and generates a difference brightness image,
A determination step in which a dense region of sipes is detected from the brightness distribution of the differential luminance image obtained in the image processing step, and the tire from which the differential luminance image in which the density of sipes is detected is determined as a winter tire is determined.
A judgment result notification step for notifying the judgment result obtained by the judgment step ,
Includes a tire detection step, which detects tires that pass through the shooting area of the shooting step .
This tire detection step
The shooting position of the high-sensitivity shooting device and the extension area passing through the position of the tire passing through the shooting area are irradiated with a rear ray from the side of the vehicle equipped with the tire to be shot toward the tire.
When the tire passes through the shooting area, the rear light received by the high-sensitivity shooting device is blocked by the passing tire, and the time when the high-sensitivity shooting device detects the shadow of the tire is defined as the time when the tire is detected. ,
The shooting step extracts an image taken at the time when the tire is detected in the tire detection step, and uses this as a visible image.
It is characterized by that.

Further, the method for discriminating a winter tire according to the present invention is the above method.
The judgment result notification step is
In addition to displaying a display indicating that the tire targeted for shooting is a winter tire and a notification indicating that it is not a winter tire,
The feature is that the worker is notified by voice of the determination result of whether or not the tire is a winter tire, and the presence of a vehicle equipped with a tire that is not determined to be a winter tire is notified.

In order to achieve the above object, the winter tire discrimination system according to the present invention is used.
Irradiation means that irradiates the tread surface of the tires of the vehicle with light rays from diagonally forward of the traveling vehicle to the outside of one of the traveling paths across the traveling path of the vehicle.
A photography means for generating a visible image by photographing the tread surface of a tire irradiated with light rays by the irradiation means via a high-sensitivity photographing device outside the other traveling path across the traveling path of the vehicle.
A brightness image is generated from the generated visible image, the generated brightness image is smoothed to generate a smoothed image, the smoothed image is differentiated from the brightness image to remove unevenness, and a difference brightness image is generated. Image processing means and
A determination means for detecting a dense region of sipes from the brightness distribution of the generated differential luminance image and determining the tire from which the differential luminance image in which the density of sipes was detected is taken as a winter tire.
Judgment result notification means for notifying the judgment result ,
A tire detection means that detects tires that pass through the shooting area ,
Equipped with
This tire detection means
The shooting position of the high-sensitivity shooting device and the extension area passing through the position of the tire passing through the shooting area are provided with rear lighting means for irradiating the rear light beam from the side of the vehicle equipped with the tire to be shot toward the tire. death,
When the tire passes through the shooting area, the rear light received by the high-sensitivity shooting device is blocked by the passing tire, and the tire detects the time when the high-sensitivity shooting device detects the shadow of the tire caused by the blocking. When it was detected
The photographing means extracts an image taken at the time when the tire is detected by the tire detecting means from the images obtained by the photographing means, and uses this as a visible image.
It is characterized by that.

Further, the winter tire discrimination system according to the present invention is the above-mentioned discrimination system.
Judgment result notification means
An image display means for displaying a display indicating that the tire to be photographed is a winter tire and a notification indicating that the tire is not a winter tire.
It is characterized by being provided with a notification means for notifying the worker of the determination result of whether or not the tire is a winter tire by voice and notifying the approach of a vehicle equipped with a tire that is not determined to be a winter tire.

Further, the winter tire discrimination system according to the present invention is the above-mentioned discrimination system.
An irradiation means is arranged on one side and a high-sensitivity photographing device is arranged on the other side of the vehicle equipped with the tire to be discriminated.
The tire to be discriminated is the tire on the irradiation means side, and the irradiation means irradiates the tire in the vicinity of the irradiation means.
The high-sensitivity photographing device is characterized in that it photographs the tire on the side far from the high-sensitivity photographing device.

In the above-mentioned invention, by taking a picture through a high-sensitivity taking picture device, the tire to be taken is used for winter without being affected by the illuminance environment such as day and night weather and the dry or wet state of the tread surface of the tire. Whether or not it is a tire can be stably determined.
Further, in the present invention, by performing differential luminance image processing on the visible image, it becomes possible to extract a dense region of sipes from the tread image of the tire.
Further, in the present invention, since the system can be configured inexpensively and compactly, it is easy to install and withdraw, and since the image processing is also executed by a simple logic, the passage of the vehicle is not interrupted. It will be possible to determine winter tires in real time, and easily identify vehicles with defective winter tires that have only incomplete sipes left and vehicles without winter tires.

FIG. 1 is a flow chart showing a flow of a method for discriminating a winter tire according to the present invention. FIG. 2 is an example of a visible image generated in the shooting step of FIG. FIG. 3 is an example of a luminance image generated in the image processing step of FIG. FIG. 4 is an example of a smoothed image generated in the image processing step of FIG. FIG. 5 is an example of a differential luminance image generated in the image processing step of FIG. FIG. 6 is an example of a visible image obtained by the discrimination system of FIG. FIG. 7 is an example of a differential luminance image obtained by image processing the visible image of FIG. 6. FIG. 8 is a sipe-extracted image showing a dense region of sipe detected from the differential luminance image of FIG. 7. FIG. 9 is a partially enlarged image obtained by enlarging the rectangular area of FIG. FIG. 10 is a table showing test results by the method for discriminating winter tires of FIG. 1. FIG. 11 is an explanatory diagram showing an outline of photography in the winter tire discrimination system according to the present invention. FIG. 12 is a block diagram showing a configuration of a winter tire discrimination system according to the present invention.

Hereinafter, the present invention will be specifically described with reference to the drawings.
First, a method for discriminating a winter tire according to the present invention will be described with reference to FIGS. 1 to 10.

FIG. 1 is a flow chart showing a flow of a method for discriminating a winter tire according to the present invention, FIG. 2 is an example of a visible image generated in the photographing step of FIG. 1, and FIG. 3 is an image processing step of FIG. An example of the generated brightness image, FIG. 4 is an example of a smoothed image generated in the image processing step of FIG. 1, FIG. 5 is an example of a difference brightness image generated in the image processing step of FIG. 1, FIG. 1 is an example of a visible image to be determined in the determination step of FIG. 1, FIG. 7 is an example of a differential brightness image generated from the visible image of FIG. 6, and FIG. 8 is generated from the differential brightness image of FIG. 9 is a partially enlarged image of the rectangular region of FIG. 8, and FIG. 10 is a table showing the test results by the method for discriminating the winter tire of FIG. 1.

In FIG. 1, S01 is an irradiation step, S02 is a shooting step, S03 is a tire detection step, S04 is an image processing step, S05 is a determination step, and S06 is a determination result notification step.

In the method for discriminating winter tires according to the present invention, discriminating is performed at a position close to the travel path of the vehicle.
When the discrimination method according to the present invention is started, the irradiation step S01 is first executed.

In this irradiation step S01, the light passing region of the tire is irradiated with light so that the tread surface of the tire of the vehicle passing through the predetermined traveling path can be obliquely irradiated with the light light from outside the passing region of the tire. Prepare for the passage of tires.
Then, when the tire passes within a predetermined range, the tread surface of the tire is irradiated with light rays from an oblique angle.
The tread surface referred to here refers to the outer peripheral surface of the tire in which the tire groove is carved.

Next, a high-sensitivity photographing device arranged so that the tread surface of the tire irradiated with the light beam in the irradiation step S01 can be photographed from the opposite side of the light ray in the irradiation step S01 across the passing region of the tire is used. , The tread surface of the tire irradiated with the light beam is photographed, and the photographing step S02 for generating a visible image is executed based on the information of the tire detection time described later.

Along with this shooting step S02, for example, a tire detection step S03 is executed in which a tire passing through the shooting region of the shooting step S02 is detected using a laser range finder and information on the tire detection time is output.

In the shooting step S02, from the images obtained by the high-sensitivity shooting device, an image taken at the tire detection time based on the tire detection time information output in the tire detection step S03 is as shown in FIG. Extract as a visible image.

Since the irradiation step S01, the photographing step S02, and the tire detection step S03 need only be in the execution state when the tire crosses the photographing area, the start order of each step is not limited to the above order, and all of them are not limited to the above order. May be started at the same time, for example, the execution of the shooting step may be started first.

Next, an image processing step of generating a differential luminance image from the visible image obtained in the shooting step S02 is executed.
In this image processing step S04, first, a luminance image as shown in FIG. 3, that is, a monochrome visible image is generated from the visible image obtained in the photographing step S02.
In this luminance image, it can be confirmed that the illumination is reflected as reflection, the luminance differs depending on how the illumination hits, and unevenness occurs.

Next, the generated luminance image is smoothed to generate a smoothed image as shown in FIG. 4, that is, a luminance distribution image.
Note that this brightness image smoothing is a kind of image filtering, and is a conventionally known technique for averaging image information by averaging the brightness of a plurality of pixels surrounding a specific pixel. Detailed explanation is omitted in the book.

Next, the smoothed image is differentiated from the luminance image to remove the unevenness, and a differential luminance image as shown in FIG. 5 in which the luminance distribution unevenness is removed is generated.
In the luminance image of FIG. 3, as described above, the reflection of light rays is reflected on the wet tread surface, and the presence or absence of sipes is not clear.

On the other hand, in the difference luminance image of FIG. 5, it can be confirmed that the reflection element is removed or reduced as noise by the difference processing, the sipes contained in the tire tread can be clearly confirmed, and the discrimination accuracy is improved.

Therefore, a dense region of sipes is detected from the brightness distribution of the differential luminance image obtained in the image processing step S04, and the tire from which the differential luminance image in which the density of sipes is detected is taken is determined as a winter tire. The determination step S05 is executed.

Here, the image obtained in the process of detecting the dense region of the sipes in the determination step S05 will be described.
In this determination step S05, the determination process is executed based on the difference brightness image shown in FIG. 7 obtained in the image processing step S04 from the visible image shown in FIG. 6 obtained in the photographing step S02.

Specifically, an image process for emphasizing the brightness of the sipe portion is executed on the difference brightness image of FIG. 7.
By this image processing, the sipe-extracted image shown in FIG. 8 is generated.
Then, in the sipe extraction image of FIG. 8, the region surrounded by the rectangle including the tread surface of the tire is extracted and enlarged, and the partially enlarged image shown in FIG. 9 is generated.

In this partially enlarged image, a dense region of sipes can be confirmed as a black line inside the gray region, and the dense region of the sipes is extracted and evaluated.

In this evaluation, when a dense region of sipes is extracted, the tire from which the acquired image to be evaluated is taken is determined as a winter tire.
As a result, when the dense region of the sipes is not extracted, it is determined that the tire from which the acquired image to be evaluated is taken is not a winter tire.

After the determination step S05 determines whether or not the tire is a winter tire, the determination result neglect step S06 is executed.
In this determination result step S06, a display indicating that the tire to be photographed is a winter tire and a display indicating that the tire is not a winter tire are displayed to the worker by, for example, a sign board or an indicator light. Then, the judgment result can be visually confirmed intuitively, and the vehicle equipped with the tire that is the judgment target can be identified.

In the above display, a signal light and a sign board are installed beside the vehicle's driving path so that the driver of the vehicle to be judged can be visually recognized in addition to the worker, and the vehicle is judged not to have winter tires. It is recommended to turn on the "red light" and "rare" signs for the driver.

In addition to the above display, when a vehicle equipped with a tire determined not to be a winter tire passes, the worker is notified by a voice, for example, a warning sound, and the tire is not determined to be a winter tire. Notify the existence of the vehicle equipped with the tire and make it possible to respond to the target vehicle.

A test using the above-mentioned method for discriminating winter tires was carried out, and the test results are shown in FIG.
In this test, wet and dry conditions were interwoven, and 60 test subjects were judged.
As a result, the discrimination accuracy was 98.3% = (35 + 24) / 60.

During this test, there was only one erroneous judgment that the studless tire was judged to be a normal tire, which was a judgment on the safety side.
From the above results, it was verified that the discrimination of winter tires using the above differential luminance image is an extremely effective discrimination means.

In the above description, the laser rangefinder is used in the tire detection step, but a method other than the laser rangefinder may be used as long as the timing of the tire passing through the photographing region can be specified.
For example, first, the shooting position of the high-sensitivity shooting device and the extension region passing through the position of the tire passing through the shooting region are irradiated with a back ray from the side of the vehicle equipped with the tire to be shot toward the tire.
Next, when the tire passes through the shooting area, the back light received by the high-sensitivity shooting device is blocked by the passing tire, and the tire is detected when the high-sensitivity shooting device detects the shadow of the tire. Specify as the time.
Then, a specific example is given in which the shooting step extracts an image taken at the time when the tire is detected in the tire detection step and uses this as a visible image.
In the case of tire detection using this back ray, the position of the tire can be detected using a high-sensitivity photographing device, so that it is not necessary to consider the delay in signal processing that occurs when a laser rangefinder is used. There is an advantage.

Next, an outline of the installation of the winter tire discrimination system according to the present invention will be described with reference to FIG.
FIG. 11 is an explanatory diagram showing an outline of photography in the winter tire discrimination system according to the present invention.

In the figure, 1 is a tire, 20 is an irradiation means, 21 is a shooting means, 22 is a tire detecting means, A is a traveling direction, B is an irradiation direction, and C is a shooting direction.
The tire 1 is one of the tires mounted on the vehicle and travels along the traveling direction A.

The irradiation means 20 is, for example, meta-halide lighting including a plurality of metal halide lamps.
The irradiation means 20 is provided outside the travel path on one side of the travel path of the vehicle equipped with the tire, in the irradiation direction B close to the road surface from diagonally forward of the vehicle (not shown) with respect to the tread surface of the tire 1. It is provided so that light rays can be emitted along the line.
The irradiation means 20 includes glare prevention means (not shown) so that the light source cannot be seen from the driver's seat of the vehicle.

The photographing means 21 generates a visible image via a high-sensitivity photographing device.
The high-sensitivity photographing device of the photographing means 21 sandwiches the traveling path of the vehicle on which the tire is mounted, and the tire 1 is irradiated to the outside of the traveling path on the side opposite to the side where the irradiation means 20 is provided. The tread surface is provided so that shooting can be performed with the shooting direction C as the shooting axis.

The tire detecting means 22 is a laser range finder provided in the vicinity of the photographing means 21.
The laser range finder of the tire detecting means 22 measures the distance from the tire 1 with the measuring direction D as the measuring axis, thereby specifying the time when the tire 1 passes through the shooting area of the shooting means 21, and the passing time. Information is output.

Next, the configuration of the winter tire discrimination system according to the invention shown in FIG. 11 will be described with reference to FIG. 12.
FIG. 12 is a block diagram showing a configuration of a winter tire discrimination system according to the present invention.

In the figure, 20 is an irradiation means, 21 is a photographing means, 22 is a tire detecting means, 30 is a central control device, 31 is an image processing device, 32 is a determination means, 33 is a determination result notification means, and 330 is an image display means 331. Is a means of notification.

In this figure, the irradiation means 20, the photographing means 21, and the tire detecting means 22 are the same as those described in FIG. 11, so duplicate description will be omitted below.

FIG. 12 shows the configuration of a position embodiment of the winter tire discrimination system.
The central control device 30 controls the operation of the system, and is connected to components (not shown) necessary for the operation and operation of the system, such as a memory, a storage medium, and an input means.

Since the operations and operations of these components (not shown) are well known, they will be omitted in the following description unless there is a particular need.
Further, since the operation of this system is the same as the description based on FIG. 1, only the outline of the description overlapping with the description of FIG. 1 will be described below.

The central control device 30 is directly or indirectly connected to each component of the system and controls the operation of each component to execute the determination of the winter tire.
The central control device 30 controls various operations according to an input operation performed by a worker or an operator via an input means (not shown), for example, a keyboard, an operation panel, a touch panel, or the like.

The irradiation means 20 is connected to the central control device 30, and the operation of starting execution of the determination by this system is performed, so that the irradiation of light rays is started according to the start signal from the central control device 30.

The photographing means 21 is connected to the central control device 30, and the operation of starting the execution of the determination by this system is performed, so that the photographing means starts according to the start signal from the central control device 30.
The image obtained by the photographing means 21 is stored in a storage medium (not shown) together with information indicating the photographing time.

The tire detecting means 22 is connected to the central control device 30 and transmits information indicating the time when the tire is detected to the central control device 30.
The photographing means 21 is connected to the central control device 30 and is visible by extracting an image of the same time as or closest to the information indicating the time when the tire is detected from the image stored in a storage medium (not shown). An image is generated and the visible image is stored in a storage medium (not shown).

The generation of the visible image is directly executed by the photographing means 21 here, but the central control device 30 may execute the generation according to a predetermined program based on the stored visible image.

The image processing means 31 is connected to the central control device 30, and first generates a luminance image from the visible image generated by the photographing means 21.
Next, the image processing device 31 smoothes the generated luminance image to generate a smoothed image.
Next, the image processing device 31 differentials the smoothed image from the luminance image to remove unevenness, generates a differential luminance image, and stores the generated luminance image in a storage medium (not shown).

The determination means 32 is connected to the central control device 30, detects a dense region of sipes from the brightness distribution of the generated differential luminance image, and determines the tire that is the source of the differential luminance image in which the density of sipes is detected. It is judged as a winter tire and the judgment result is output.

On the other hand, when the dense region of the sipes is not detected, the determination means 32 determines that the tire that is the shooting source is not a winter tire, and outputs the determination result.
The output of the determination result that the tire is not for winter is not essential and may be omitted.

The determination result notification means 33 is connected to the central control device 30 and includes an image display means 330 and a notification means 331.
The image display means 330 is, for example, a display device, a display panel, a traffic light, a mobile terminal, and is provided so as to be identifiable by an operator, an operator, a vehicle driver, or the like, if necessary.

The notification means 331 is, for example, a speaker, an earphone, a headset, or the like, and is provided so as to generate at least a voice or a warning sound that can be heard by an operator who can approach the vehicle to be discriminated.

In the determination result notification means 33, the vehicle equipped with the tire determined not to be a winter tire approaches the worker who waits at a predetermined worker waiting place in the vicinity of the vehicle's travel path from the determination means 32. This is displayed on the image display means 330, and a warning sound or the like is notified from the notification means 331 to notify the worker.

At this time, by turning on the red light at the traffic light, the driver of the vehicle equipped with the tire determined not to be a winter tire may be urged to stop the vehicle.
Workers who receive these notifications and notifications can stop the corresponding vehicle, check the tires, and take necessary guidance and measures.

On the contrary, when a vehicle equipped with a tire determined to be a winter tire approaches the worker's waiting area, at least the worker is informed that there is no problem and voice notification is executed as necessary. , Does not notify workers to stop the corresponding vehicle.

In the above embodiment, the image processing of the image processing means 31 can eliminate the influence of snow and water spray, and can confirm the presence or absence of tire tread and sipes without being affected by the illuminance environment (whether day or night).

Further, the difference brightness image of FIG. 7 can be subjected to image processing to emphasize the brightness of the sipe portion to generate a sipe extraction image, and the region including the tire tread surface can be automatically detected from the image. Therefore, it is possible to automatically correct the deviation of the shooting position of the tire that moves due to running and determine whether or not the tire is a winter tire.

The winter tire discrimination system according to the present invention can be operated, for example, by saving space within a range of about 30 m per lane within the winter tire restricted area.
By introducing the winter tire discrimination system according to the present invention, it is possible to save labor for discrimination for preventing entry into the winter tire restricted area.

In addition, workers and traffic control staff can check the judgment results in real time, so that vehicles without winter tires can be quickly guided. For example, traffic congestion on the main line due to stagnant vehicles. Can be alleviated, and improvement in safety can be expected.

Further, in this system, by using a high-sensitivity photographing device, for example, an industrial high-definition camera, the discrimination can be performed without extremely slowing down the speed of the vehicle to be discriminated, so that smooth traffic is not hindered. ..

In addition, in this system, whether or not the tire is a winter tire is determined by detecting a dense area of the sipe, and a vehicle that is not allowed to enter the winter tire restricted area is determined. It will also be possible to identify the vehicle whose part has disappeared.

In the above embodiment, a part of the acquired image and various processed images are recorded in the storage medium, but the recorded image information is not limited to the above embodiment, for example. You may record everything, or you may not record it, but you may execute processing such as generation inside the shooting means, image processing means, etc., and notify the determination result.

In addition, the notification of the judgment result is given to the worker by the display by the traffic light and the notification of the voice, and the judgment result by the image generated by the processing and the character information is provided for the operator different from the worker. It may be displayed on a display device or the like.

Further, in this embodiment, the central control device, the image processing means, the determination means, and the determination result notification means are substituted by the functions included in the device such as a commercially available personal computer or mobile terminal, and the device is used for the irradiation means and the photographing. The means, the tire detecting means, the image display means for the worker, and the notifying means may be externally configured.

In addition, the visible image generated by the photographing means is pinpointed at the timing when the sensor other than the laser rangefinder that detects the passage of the tire detects the tire, and the presence of the tire is estimated according to the timing. It may be acquired only for a certain period of time and a visible image may be generated.

For example, a rear lighting means that irradiates a rear light beam from the side of a vehicle equipped with a tire to be photographed toward the tire in an extension area passing through a shooting position of a high-sensitivity shooting device and a position of a tire passing through the shooting area. When the tire passes through the shooting area, the rear light beam received by the high-sensitivity photographing device is blocked by the passing tire, and the high-sensitivity photographing device detects the shadow of the tire caused by the blocking. The time is defined as the time when the tire is detected, and the photographing means extracts an image taken at the time when the tire is detected by the tire detecting means from the images obtained by the photographing means, and uses this as a visible image. You may do so.

Further, in the above embodiment, the tire on the side far from the lighting means is used as the tire to be discriminated, and the tire on the side close to the high-sensitivity photographing device is used as the tire to be discriminated. However, the tire to be discriminated is irradiated. The tire may be the tire on the means side, the irradiation means may irradiate the tire in the vicinity of the irradiation means, and the high-sensitivity photographing device may photograph the tire on the side far from the high-sensitivity photographing device.

In this case, the tire to be discriminated is close to the lighting means, the tire to be discriminated can be illuminated more brightly, and a clear visible image can be generated.
Further, in this case, it becomes easy to move the shooting position away from the tire to be discriminated, and by lengthening the focal length, it is possible to make an object near the shooting position out of focus and make it difficult to be reflected in a visible image. It is possible to reduce the adverse effects of snowfall.

The present invention has a low-cost and compact system configuration that distinguishes between a vehicle equipped with winter tires and a vehicle not equipped with winter tires without being affected by the illuminance environment such as day and night weather and the dry or wet state of the tread surface of the tire. In addition, it can be carried out smoothly, easily and reliably with a small number of personnel, and it will be possible to efficiently prevent improper vehicle entry into the winter tire regulation section, road maintenance, maintenance, accidents. Very useful for prevention.

Claims (5)

An irradiation step of diagonally irradiating a tread surface of a vehicle tire passing through a predetermined driving path with a light beam from outside the tire passing region.
The tread surface of the tire irradiated with light rays in the irradiation step is photographed with a high-sensitivity photographing device from the opposite side of the passing area of the tire with the light rays of the irradiation step, and a photographing step of generating a visible image.
A brightness image (monochrome visible image) is generated from the visible image obtained in the shooting step, the generated brightness image is smoothed to generate a smoothed image (brightness distribution image), and a smoothed image is obtained from the brightness image. An image processing step that makes a difference, removes unevenness, and generates a difference brightness image,
A determination step in which a dense region of sipes is detected from the brightness distribution of the differential luminance image obtained in the image processing step, and the tire from which the differential luminance image in which the density of sipes is detected is determined as a winter tire is determined.
A judgment result notification step for notifying the judgment result obtained by the judgment step ,
A tire detection step that detects tires that pass through the shooting area of the shooting step,
Including
This tire detection step
The shooting position of the high-sensitivity shooting device and the extension area passing through the position of the tire passing through the shooting area are irradiated with a rear ray from the side of the vehicle equipped with the tire to be shot toward the tire.
When the tire passes through the shooting area, the rear light received by the high-sensitivity shooting device is blocked by the passing tire, and the time when the high-sensitivity shooting device detects the shadow of the tire is defined as the time when the tire is detected. ,
The shooting step extracts an image taken at the time when the tire is detected in the tire detection step, and uses this as a visible image.
How to identify winter tires. The judgment result notification step is
In addition to displaying a display indicating that the tire targeted for shooting is a winter tire and a notification indicating that it is not a winter tire,
The winter tire according to claim 1, which notifies the worker of the determination result of whether or not the tire is a winter tire by voice and notifies the existence of a vehicle equipped with a tire that is not determined to be a winter tire. Discrimination method. Irradiation means that irradiates the tread surface of the tires of the vehicle with light rays from diagonally forward of the traveling vehicle to the outside of one of the traveling paths across the traveling path of the vehicle.
An imaging means for generating a visible image by photographing the tread surface of the tire irradiated by the irradiation means outside the other traveling path across the traveling path of the vehicle through a high-sensitivity photographing device.
A brightness image is generated from the generated visible image, the generated brightness image is smoothed to generate a smoothed image, the smoothed image is differentiated from the brightness image to remove unevenness, and a difference brightness image is generated. Image processing means and
From the brightness distribution of the generated differential luminance image, a determination means for detecting a dense region of sipes and determining the tire from which the differential luminance image in which the density of sipes was detected is taken as a winter tire, and the determination result are determined. Judgment result notification means to notify and
A tire detection means that detects tires that pass through the shooting area,
Equipped with
This tire detection means
The shooting position of the high-sensitivity shooting device and the extension area passing through the position of the tire passing through the shooting area are provided with rear lighting means for irradiating the rear light beam from the side of the vehicle equipped with the tire to be shot toward the tire. death,
When the tire passes through the shooting area, the rear light received by the high-sensitivity shooting device is blocked by the passing tire, and the tire detects the time when the high-sensitivity shooting device detects the shadow of the tire caused by the blocking. When it was detected
The photographing means extracts an image taken at the time when the tire is detected by the tire detecting means from the images obtained by the photographing means, and uses this as a visible image.
Winter tire discrimination system. Judgment result notification means
An image display means for displaying a display indicating that the tire to be photographed is a winter tire and a notification indicating that the tire is not a winter tire.
The third aspect of claim 3 , wherein the worker is notified of the determination result of whether or not the tire is a winter tire by voice, and the notification means is provided to notify the approach of a vehicle equipped with a tire that is not determined to be a winter tire. Winter tire discrimination system. An irradiation means is arranged on one side and a high-sensitivity photographing device is arranged on the other side of the vehicle equipped with the tire to be discriminated.
The tire to be discriminated is the tire on the irradiation means side, and the irradiation means irradiates the tire in the vicinity of the irradiation means.
The winter tire discrimination system according to claim 3 or 4 , wherein the high-sensitivity photographing device photographs a tire on a side far from the high-sensitivity photographing device.

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