JP2021104740A - Tire air pressure reduction degree determination device, tire air pressure reduction degree determination method and program - Google Patents

Abstract

To provide a tire air pressure reduction degree determination device, a tire air pressure reduction degree determination method and a program which can easily determine a reduction degree of a tire air pressure.SOLUTION: A photographic image acquisition part 64 acquires a photographic image that is a depth image or a three-dimensional image showing a side face of a tire provided on a vehicle. A deformation amount specification part 68 specifies a deformation amount of the tire on the basis of the photographic image. An air pressure reduction degree determination part 70 determines a determination degree of an air pressure of the tire on the basis of a specified deformation amount.SELECTED DRAWING: Figure 8

Description

The present invention relates to a tire pressure drop determination device, a tire pressure drop determination method and a program.

Patent Document 1 describes a tire pressure drop detection method capable of identifying a tire whose pressure is reduced among four-wheel tires based on the wheel speed obtained from the tire.

Patent Document 2 describes a tire pressure drop warning method for detecting that four wheels are simultaneously depressurized from the rotation speed of the wheels.

Japanese Unexamined Patent Publication No. 2004-161127 Japanese Unexamined Patent Publication No. 2006-27298

In the technique described in Patent Document 1, in order to detect the decompression of the tire, it is necessary to bother to provide a sensor such as a wheel speed sensor or an angular velocity sensor for determining a decrease in the tire pressure. Similarly, in the technique described in Patent Document 2, in order to detect the decompression of the tire, it is necessary to bother to provide a means for detecting the rotational speed of the wheel.

The present invention has been made in view of the above circumstances, and one of the objects thereof is to provide a tire pressure reduction degree determination device, a tire air pressure reduction degree determination method, and a program capable of easily determining the tire pressure reduction degree. To do.

In order to solve the above problems, the tire pressure drop determination device according to the present invention includes a photographed image acquisition means for acquiring a photographed image which is a depth image or a three-dimensional image showing a side surface of a tire provided in a vehicle, and the photographed image. Includes a deformation amount specifying means for specifying the deformation amount of the tire based on the above, and a determination means for determining the degree of decrease in the air pressure of the tire based on the deformation amount.

One aspect of the present invention further includes a detecting means for detecting that the vehicle is in the photographing range, and the captured image acquisition means is photographed in response to the detection that the vehicle is in the photographing range. The photographed image is acquired.

Further, in one aspect of the present invention, the determination means determines the degree of decrease in the air pressure of the tire based on a plurality of the photographed images continuously photographed for one tire.

Further, in one aspect of the present invention, the determination means determines the air pressure of the plurality of tires based on the comparison result of the amount of deformation specified for each of the plurality of tires provided in the vehicle. Determine the degree of decline.

Alternatively, the modification further includes a target image generation means for generating a target image in which the size of the area where the wheel appears is a given size by cutting out a part of the image in which the size of the captured image is changed. The amount specifying means specifies the amount of deformation of the tire based on the target image.

Alternatively, the target image generation means for generating a target image in which the size of the area where the wheel appears is a given size by changing the size of the image obtained by cutting out a part of the captured image is further included. The deformation amount specifying means specifies the deformation amount of the tire based on the target image.

In the above two aspects, the target image generation means generates the target image of the tire based on the photographed image showing the side surface of the tire for each of the plurality of tires included in the vehicle. The determination means may determine the degree of decrease in air pressure of the plurality of tires based on the comparison result of the amount of deformation specified based on the target image of the tire for each of the plurality of tires. ..

Further, in one aspect of the present invention, the deformation amount specifying means is the distribution of the height of the tire, the amount of curvature of the side surface of the tire, or the distance from the position where the photographed image is taken to the surface of the tire. The amount of deformation indicating at least one of the above is specified.

Further, the method for determining the degree of decrease in tire pressure according to the present invention includes a step of acquiring a captured image which is a depth image or a three-dimensional image showing the side surface of the tire provided in the vehicle, and the amount of deformation of the tire based on the captured image. A step of determining the degree of decrease in the air pressure of the tire based on the amount of deformation is included.

Further, the program according to the present invention includes a procedure for acquiring a captured image which is a depth image or a three-dimensional image showing a side surface of a tire provided in a vehicle, a procedure for specifying a deformation amount of the tire based on the captured image, and the above-mentioned. A computer is made to execute a procedure of determining the degree of decrease in the air pressure of the tire based on the amount of deformation.

It is a figure which shows an example of the structure of the tire pressure drop degree determination device which concerns on one Embodiment of this invention. It is a figure which shows an example of the upper surface of a vehicle schematically. It is a figure which shows an example of the relationship of a high-speed sampling period, a front wheel photography period, and a rear wheel photography period schematically. It is a figure which shows an example of a high-speed sampling image. It is a figure which shows an example of a target image. It is a figure which shows an example of a target image. It is a figure which shows an example of a target image. It is a functional block diagram which shows an example of the function of the tire pressure drop degree determination device which concerns on one Embodiment of this invention. It is a flow chart which shows an example of the flow of the process performed by the tire pressure drop degree determination apparatus which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an example of the configuration of a tire pressure drop degree determining device 10 according to an embodiment of the present invention. The tire pressure drop determination device 10 according to the present embodiment is a computer such as a personal computer. As shown in FIG. 1, the tire pressure drop determination device 10 includes, for example, a processor 12, a storage unit 14, a communication unit 16, a display unit 18, an operation unit 20, and a photographing unit 22.

The processor 12 is, for example, a program control device such as a CPU that operates according to a program installed in the tire pressure drop degree determination device 10.

The storage unit 14 is a storage element such as a ROM or RAM, a hard disk drive, or the like. The storage unit 14 stores a program or the like executed by the processor 12.

The communication unit 16 is a communication interface such as a network board.

The display unit 18 is a display device such as a liquid crystal display, and displays various images according to the instructions of the processor 12.

The operation unit 20 is a user interface such as a keyboard or a mouse, receives an operation input of the user, and outputs a signal indicating the contents to the processor 12.

The shooting unit 22 is a shooting device such as a stereo camera capable of shooting a three-dimensional image or a depth camera capable of shooting a depth image, and outputs the three-dimensional image or the depth image generated by the shooting to the processor 12. The tire pressure drop determination device 10 according to the present embodiment may include a plurality of photographing units 22. Further, the photographing unit 22 may be a video camera capable of photographing a three-dimensional moving image including a series of three-dimensional images and a depth moving image including a series of depth images.

The tire pressure drop determination device 10 may include an optical disk drive for reading an optical disk such as a DVD-ROM or a Blu-ray (registered trademark) disc, a USB (Universal Serial Bus) port, or the like.

In the present embodiment, the degree of decrease in the tire pressure in the image captured by the photographing unit 22 is determined.

FIG. 2 is a diagram schematically showing an example of the upper surface of a vehicle 30 provided with tires for which the degree of decrease in air pressure is determined. The vehicle 30 is traveling at a low speed, for example, just before passing through the tollhouse gate 32 on the highway. In the present embodiment, for example, it is assumed that the vehicle 30 is traveling at a speed of 20 km / h or less.

Further, in the present embodiment, for example, as shown in FIG. 2, the photographing unit 22 (22a and 22b) is provided on the side of the lane in which the vehicle 30 travels so that the photographing direction faces the center of the lane. .. In the example of FIG. 2, the photographing units 22a and 22b are arranged so that the photographing direction is perpendicular to the lane.

In the present embodiment, for example, the photographing unit 22 photographs an image at a predetermined sampling rate. Hereinafter, the image taken in this situation will be referred to as a low-speed sampling image. Then, in the present embodiment, for example, it is detected that the vehicle 30 exists in a predetermined shooting range based on a low-speed sampled image. For example, the detection of the image of the vehicle 30 from the low-speed sampled image taken by the photographing unit 22 using the image recognition technology such as the shape recognition technology, the color recognition technology, and the pattern recognition technology is such that the vehicle 30 exists in a predetermined shooting range. It may be used to trigger the detection of what to do.

Then, in response to the detection that the vehicle 30 is in the predetermined shooting range, the shooting unit 22 is controlled to start shooting at a sampling rate higher than the sampling rate of the low-speed sampling image. Hereinafter, the image taken in this situation will be referred to as a high-speed sampling image. For example, when it is confirmed that the vehicle 30 is shown in the low-speed sampling image, the high-speed sampling image is started to be taken. High-speed sampling images may be taken at predetermined time intervals.

In the present embodiment, for example, the photographing unit 22a captures a high-speed sampling image in which the side surface of the right front wheel 34 and the side surface of the right rear wheel 36 of the vehicle 30 are captured. Further, the photographing unit 22b captures a high-speed sampling image in which the side surface of the left front wheel 38 and the side surface of the left rear wheel 40 of the vehicle 30 are captured.

Then, in the present embodiment, when it is confirmed that the vehicle 30 is not shown in the high-speed sampling image, the shooting of the high-speed sampling image is terminated.

As shown in FIG. 3, hereinafter, the period during which a series of high-speed sampling images are captured in this way is referred to as a high-speed sampling period t.

In the present embodiment, for example, in the high-speed sampling period t, the front wheel shooting period t1 in which the high-speed sampling image showing the side surface of the front wheel is captured, and the rear wheel shooting period t2 in which the high-speed sampling image showing the side surface of the rear wheel is captured. Is included.

For example, the photographing unit 22a captures a high-speed sampling image in which the side surface of the right front wheel 34 is captured during the front wheel photographing period t1. Then, during the rear wheel photographing period t2, a high-speed sampling image in which the side surface of the right rear wheel 36 is captured is captured.

Further, for example, the photographing unit 22b photographs a high-speed sampling image in which the side surface of the left front wheel 38 is captured during the front wheel photographing period t1. Then, during the rear wheel photographing period t2, a high-speed sampling image in which the side surface of the left rear wheel 40 is captured is captured.

In the present embodiment, for example, from a series of high-speed sampling images continuously captured during the high-speed sampling period t, a series of high-speed sampling images captured during the front wheel imaging period t1 and a series captured during the rear wheel imaging period t2. High-speed sampling image is identified.

In the present embodiment, for example, using image recognition technology such as shape recognition technology, color recognition technology, and pattern recognition technology, a plurality of high-speed sampling images in which the side surface of the tire is captured from a series of high-speed sampling images continuously taken during the high-speed sampling period t. High-speed sampling image is identified.

In the example of FIG. 3, when the shooting of the high-speed sampling image is started, the high-speed sampling image in which the side surface of the tire is not shown is continuously shot. After that, high-speed sampling images showing the front wheels are continuously taken. Then, after a period in which the high-speed sampling image in which neither the front wheels nor the rear wheels are captured in the high-speed sampling image is continuously photographed, the high-speed sampling image in which the rear wheels are captured is continuously captured.

From the above, the plurality of high-speed sampling images showing the side surface of the tire can be classified into a series of high-speed sampling images taken at an early timing and a series of high-speed sampling images taken at a late timing. Then, a series of high-speed sampling images taken at an early timing are specified as high-speed sampling images taken during the front wheel shooting period t1. Further, a series of high-speed sampling images taken at a late timing are specified as high-speed sampling images taken during the rear wheel shooting period t2.

As described above, from the series of high-speed sampling images taken by the photographing unit 22a, a series of high-speed sampling images showing the side surface of the right front wheel 34 and a series of high-speed sampling images showing the side surface of the right rear wheel 36 are specified. NS. Further, from the series of high-speed sampling images taken by the photographing unit 22b, a series of high-speed sampling images in which the side surface of the left front wheel 38 is captured and a series of high-speed sampling images in which the side surface of the left rear wheel 40 is captured are specified.

It is conceivable that the side surface of the front wheel and the side surface of the rear wheel are captured in the high-speed sampling image. In this case, the front wheel shooting period t1 and the rear wheel shooting period t2 partially overlap.

FIG. 4 is a diagram showing an example of a high-speed sampling image in which the left front wheel 38 is captured, which is captured by the photographing unit 22b. Then, in the present embodiment, for example, the target image illustrated in FIG. 5 is generated based on the high-speed sampling image shown in FIG.

Here, for example, by using an image recognition technique such as a shape recognition technique, a color recognition technique, or a pattern recognition technique, the target area 42, which is a quadrangular area showing the side surface of the tire, is cut out from the high-speed sampled image to obtain the target image. May be generated.

Here, a partial image may be generated by cutting out the target region 42 from the high-speed sampling image. Then, the target image may be generated by resizing (enlarging or reducing) the partial image so that the size of the region where the wheel 44 appears becomes a predetermined size. For example, the target image may be generated by resizing the partial image so that the number of pixels in the diameter of the region where the wheel 44 appears is a predetermined number of pixels r. Further, the target image may be generated by deforming the partial image by affine transformation or the like so that the shape of the region where the wheel 44 appears becomes a perfect circle.

Alternatively, an image in which the high-speed sampling image is resized so that the size of the region where the wheel 44 appears becomes a predetermined size may be generated. For example, an image in which the high-speed sampling image is resized so that the number of pixels in the diameter of the region where the wheel 44 appears is a predetermined number r may be generated. Here, an image in which the size of the high-speed sampled image is deformed by affine transformation or the like is resized so that the shape of the region where the wheel 44 appears becomes a perfect circle may be generated. Then, a target image may be generated by cutting out an image of a region showing the side surface of the tire from the resized image.

Then, in the present embodiment, for example, the amount of deformation d of the tire reflected in the target image is specified based on the target image.

Here, for example, considering that the height of the tire decreases as the air pressure decreases, as shown in FIG. 5, the value indicating the number of pixels h corresponding to the height of the tire is the value indicating the amount of deformation d of the tire. May be specified as.

Further, considering that the difference in bulge between the upper part and the lower part of the tire increases as the air pressure decreases, the value indicating the amount of curvature c on the side surface of the tire may be specified as the value indicating the amount of deformation d of the tire. .. Here, for example, the distance from the position where the high-speed sampling image is taken to the surface of the tire may be specified for each of the pixels showing the side surface of the tire in the target image. For example, the position where the photographing unit 22 is arranged corresponds to the position where the high-speed sampled image is photographed. Hereinafter, the distance from the position where the high-speed sampling image is taken to the surface of the tire will be referred to as depth. Then, a value obtained by subtracting the minimum value from the maximum value of the depth may be specified as a value indicating the amount of curvature c.

Further, for example, as shown in FIG. 6, the upper region 46 and the lower region 48, in which the relative positions in the region where the side surface of the tire appears in the target image are predetermined, may be specified. .. The upper region 46 shows a part of the upper part of the side surface of the tire, and the lower region 48 shows a part of the lower part of the side surface of the tire.

Then, the depth may be specified for each of the pixels in the upper region 46. Further, the depth may be specified for each of the pixels in the lower region 48.

Then, a value obtained by subtracting the minimum value of the depth specified for the pixel in the lower region 48 from the maximum value of the depth specified for the pixel in the upper region 46 may be specified as a value indicating the bending amount c.

Further, based on the fact that the bulge of the tire changes as the air pressure decreases, as shown in FIG. 7, the depth distribution for each pixel in the side surface region 50 in which the side surface of the tire appears in the target image is shown. The value may be specified as a value indicating the amount of deformation d of the tire. Hereinafter, the depth distribution for each pixel in the side surface region 50 will be referred to as a side profile p.

Here, for example, the reference depth z1 which is the depth for the pixel corresponding to the center of the wheel 44 appearing in the target image may be specified. Then, a value z2 indicating the difference between the depth and the reference depth z1 for each pixel in the side surface region 50 may be specified. Then, the distribution of the value z2 for each pixel in the side surface region 50 specified in this way may be specified as a value indicating the side profile p.

As the value indicating the side profile p, a value indicating the depth distribution for all the pixels in the side surface region 50 may be used, or the depth for each pixel in the specific region in the side surface region 50 may be used. A value indicating the distribution of may be used.

In the present embodiment, the amount of deformation d for each of the four tires included in the vehicle 30 is specified.

Here, for example, any one may be selected from a series of high-speed sampling images showing the side surface of the tire. For example, a high-speed sampling image taken in the middle of the front wheel shooting period t1 or a high-speed sampling image taken in the middle of the rear wheel shooting period t2 may be selected. Then, the deformation amount d of the tire may be specified by executing the above-mentioned processing on one selected high-speed sampling image.

Alternatively, for example, the above-mentioned processing may be executed on a part or all of a series of high-speed sampling images showing the side surface of the tire to specify the deformation amount d corresponding to the high-speed sampling image. Then, the representative value (for example, the average value) of the deformation amount d specified in this way may be specified as the deformation amount d of the tire.

Then, the degree of decrease in the air pressure of each tire is determined based on the comparison result of the four deformation amounts d specified for each of the four tires. Here, for example, the degree of decrease in the air pressure of each tire may be determined based on the difference in the values indicating the amount of deformation d.

For example, it is assumed that the values d1, d2, d3, and d4 indicating the amount of deformation are specified for the right front wheel 34, the right rear wheel 36, the left front wheel 38, and the left rear wheel 40, respectively. At this time, if the difference between the value of d1 and the value of d2, the difference between the value of d1 and the value of d3, and the difference between the value of d1 and the value of d4 are all larger than a predetermined threshold value, the right It may be determined that the air pressure of the front wheels 34 is low.

Further, for example, when the value indicating the dispersion of the deformation amount d is larger than a predetermined threshold value, the air pressure of the tire whose value indicating the deformation amount d is farthest from the average value of the deformation amount d for the four tires decreases. It may be determined that the tire is used.

Here, as the value of the amount of deformation d, for example, the number of pixels h corresponding to the height of the tire described above may be used.

Further, as the value of the deformation amount d, for example, the value indicating the above-mentioned bending amount c may be used.

Further, as the value of the deformation amount d, for example, the value indicating the above-mentioned side profile p may be used.

In this case, for example, the sum of the above-mentioned values z2 for all the pixels in the side surface region 50 may be used as the value indicating the side profile p.

Alternatively, for example, for two target images, the sum of squares of the differences of the above values z2 for the pixels associated with each other in the side region 50 may be specified. Then, the sum of squares of the differences identified in this way may be used as the difference between the values indicating the side profiles p for the two tires associated with these two target images.

Further, a plurality of combinations of a value indicating the number of pixels h, a value indicating the amount of curvature c, and a value indicating the side profile p may be used as the value of the amount of deformation d. Further, a value other than the value indicating the number of pixels h, the value indicating the amount of curvature c, and the value indicating the side profile p may be used as the value of the amount of deformation d.

As described above, according to the present embodiment, it is possible to easily determine the degree of decrease in the air pressure of the tire by using the image of the side surface of the tire without providing a sensor such as a wheel speed sensor or an angular velocity sensor.

The scope of application of the present invention is not limited to the situation where the vehicle 30 is traveling near the tollhouse gate 32. The present invention can also be applied to a situation where the vehicle 30 is stopped.

For example, the degree of decrease in the tire pressure of the vehicle 30 may be determined based on an image taken in response to the detection of the vehicle 30 stopping at a gas station or a parking lot. Further, the degree of decrease in the tire pressure of the vehicle 30 may be determined based on an image taken when the vehicle 30 is traveling at a low speed at a gas station or a parking lot entrance / exit.

Hereinafter, the functions mounted on the tire pressure reduction degree determination device 10 and the processing performed by the tire pressure reduction degree determination device 10 will be further described.

FIG. 8 is a functional block diagram showing an example of the functions implemented in the tire pressure drop degree determination device 10 according to the present embodiment. The tire pressure drop determination device 10 according to the present embodiment does not need to have all the functions shown in FIG. 8, and may have functions other than the functions shown in FIG.

As shown in FIG. 8, functionally, the tire pressure drop determination device 10 includes a detection unit 60, a photographing control unit 62, a photographed image acquisition unit 64, a target image generation unit 66, a deformation amount specifying unit 68, and the like. The air pressure drop degree determination unit 70 is included.

The above functions may be implemented by executing the program including the instructions corresponding to the above functions installed in the tire pressure drop degree determination device 10 which is a computer on the processor 12. This program is supplied to the tire pressure drop determination device 10 via, for example, a computer-readable information storage medium such as an optical disk, a magnetic disk, a magnetic tape, a magneto-optical disk, or a flash memory, or via the Internet or the like. You may.

In the present embodiment, the detection unit 60 detects, for example, that the vehicle 30 is in a predetermined shooting range. For example, as described above, the detection unit 60 may detect that the vehicle 30 is in a predetermined shooting range based on the low-speed sampling image taken by the shooting unit 22. The method of detecting that the vehicle 30 is within the predetermined shooting range is not limited to the method based on the low-speed sampled image.

In the present embodiment, the photographing control unit 62 controls the photographing unit 22 so as to acquire an image in which the side surface of the tire included in the vehicle 30 is captured, for example, in response to the detection that the vehicle 30 is in a predetermined photographing range. For example, when the image of the vehicle 30 is detected from the low-speed sampling image taken by the shooting unit 22, the shooting control unit 62 may transmit a shooting start instruction of the high-speed sampled image to the shooting unit 22. Then, the photographing unit 22 that has received the photographing start instruction may start photographing the high-speed sampled image.

In the present embodiment, the captured image acquisition unit 64 acquires, for example, a captured image which is a depth image or a three-dimensional image showing the side surface of the tire included in the vehicle 30. The captured image acquisition unit 64 acquires, for example, the above-mentioned high-speed sampling image taken in response to the detection that the vehicle 30 is in the above-mentioned imaging range.

In this embodiment, the target image generation unit 66 generates a target image based on, for example, a high-speed sampling image.

The target image generation unit 66 may generate a target image in which the size of the region where the wheel 44 appears is a given size by cutting out a part of the image in which the size of the high-speed sampling image is changed.

Alternatively, the target image generation unit 66 may generate a target image in which the size of the area where the wheel 44 appears is a given size by changing the size of the image obtained by cutting out a part of the high-speed sampling image. good.

Further, the target image generation unit 66 may generate a target image of the tire based on a photographed image showing the side surface of the tire for each of a plurality of tires included in one vehicle 30.

Here, as described above, a target image in which the size of the region where the wheel 44 appears is a predetermined size may be generated. Alternatively, the size of the region where the wheel 44 appears in the high-speed sampling image showing the reference tire may be specified as the reference size. Then, for other tires, a target image may be generated in which the size of the region where the wheel 44 appears is the above-mentioned reference size.

For example, the size of the area where the wheel 44 appears in the high-speed sampling image showing the right rear wheel 36, the left front wheel 38, and the left rear wheel 40 is the area where the wheel 44 appears in the high-speed sampling image where the right front wheel 34 appears. It may be resized to be the same size as. Here, it is highly possible that the right front wheel 34 and the right rear wheel 36 have substantially the same size of the region in which the wheel 44 appears. Based on this, only the high-speed sampling image showing the left front wheel 38 and the left rear wheel 40 shows the size of the area where the wheel 44 appears, and the area where the wheel 44 appears in the high-speed sampling image showing the right front wheel 34. It may be resized to be the same size.

By setting the size of the area where the wheel 44 appears in the target image to a given size, the side surface of the tire in the target image for each of the four tires appears even if the vehicle 30 is not traveling in the center of the lane. The size of the area can be made uniform.

Further, as described above, the target image generation unit 66 performs affine transformation or the like on a high-speed sampling image or an image obtained by cutting out a part of the high-speed sampling image so that the shape of the wheel 44 appearing in the target image becomes a perfect circle. It may be deformed.

In the present embodiment, the deformation amount specifying unit 68 specifies the deformation amount d of the tire, for example, based on a photographed image showing the side surface of the tire. The deformation amount specifying unit 68 may specify the deformation amount d of the tire shown in the target image based on the target image.

As described above, the deformation amount specifying portion 68 is the distribution of the height of the tire, the amount of curvature c on the side surface of the tire, or the distance from the position where the high-speed sampling image was taken to the surface of the tire (the depth described above). The deformation amount d indicating at least one of them may be specified.

In the present embodiment, the air pressure decrease determination unit 70 determines the decrease in the air pressure of the tire based on, for example, the amount of deformation d of the tire.

As described above, the air pressure decrease degree determination unit 70 may determine the air pressure decrease degree of the tire based on a plurality of high-speed sampling images continuously photographed for one tire. Further, the air pressure decrease degree determination unit 70 determines the air pressure decrease degree of the plurality of tires based on the comparison result of the deformation amount d specified for each of the plurality of tires provided in one vehicle 30. May be good. Further, the air pressure decrease degree determination unit 70 determines the air pressure decrease degree of the plurality of tires based on the comparison result of the deformation amount d specified based on the target image of the tire for each of the plurality of tires. May be good.

Here, an example of the flow of the learning process performed by the tire pressure drop degree determination device 10 according to the present embodiment will be described with reference to the flow chart illustrated in FIG. In this processing example, the shooting timing of the high-speed sampling image is synchronized between the shooting unit 22a and the shooting unit 22b, and the shooting unit 22a and the shooting unit 22b simultaneously shoot the high-speed sampling image.

First, the detection unit 60 waits until the detection unit 60 detects that the vehicle 30 is within a predetermined shooting range (S101). The detection in the process shown in S101 is performed based on, for example, a low-speed sampling image captured by the photographing unit 22a or a low-speed sampling image captured by the photographing unit 22b.

When the detection unit 60 detects that the vehicle 30 is within a predetermined shooting range, the shooting control unit 62 transmits a shooting start instruction of the high-speed sampled image to the shooting unit 22a and the shooting unit 22b (S102). The photographing unit 22a and the photographing unit 22b start taking a high-speed sampled image in response to receiving the shooting start instruction.

Then, the captured image acquisition unit 64 acquires the high-speed sampled image captured by the photographing unit 22a and the high-speed sampled image captured by the photographing unit 22b (S103).

Then, the detection unit 60 confirms whether or not the vehicle 30 is reflected in the high-speed sampling image acquired by the process shown in S103 (S104). Here, for example, it may be confirmed whether or not the vehicle 30 is captured in the high-speed sampling image captured by the photographing unit 22a. Alternatively, it may be confirmed whether or not the vehicle 30 is captured in the high-speed sampling image captured by the photographing unit 22b.

Here, when it is confirmed that the image is captured (S104: Y), the process shown in S103 based on the high-speed sampled image newly captured by the photographing unit 22a and the photographing unit 22b is executed.

It is assumed that the vehicle 30 is not shown in the high-speed sampling image acquired by the process shown in S103 (S104: N). In this case, the target image generation unit 66 specifies a high-speed sampling image showing the side surface of each of the four tires from the series of high-speed sampling images acquired by the process shown in S103 (S105). ..

Here, for example, from a series of high-speed sampling images taken by the photographing unit 22a, a series of high-speed sampling images showing the side surface of the right front wheel 34 and a series of high-speed sampling images showing the side surface of the right rear wheel 36 are specified. Will be done. Further, from the series of high-speed sampling images captured by the photographing unit 22b, a series of high-speed sampling images showing the side surface of the left front wheel 38 and a series of high-speed sampling images showing the side surface of the left rear wheel 40 are specified. ..

Then, the target image generation unit 66 generates a target image in which the tire is captured for each of the four tires included in the vehicle 30 (S106). Here, for example, at least one target image is generated for each of the four tires.

Then, the deformation amount specifying unit 68 specifies the deformation amount d of the tire reflected in the target image based on the target image generated by the process shown in S106 (S107). Here, the deformation amount specifying unit 68 may specify the deformation amount d of the tire shown in the target image based on the deformation amount d specified for each of the plurality of target images showing the side surface of one tire. ..

Then, the air pressure decrease degree determination unit 70 determines the air pressure decrease degree of each tire based on the deformation amount d specified for each of the four tires by the process shown in S107 (S108). Here, for example, a tire whose air pressure is low may be determined.

Then, the shooting control unit 62 transmits a shooting start instruction of the low-speed sampled image to the shooting unit 22a and the shooting unit 22b (S109), and the process shown in this processing example is completed. The photographing unit 22a and the photographing unit 22b start taking a low-speed sampled image in response to receiving the shooting start instruction.

In the above processing example, for example, it may be determined whether or not the side surface of the tire is reflected in the high-speed sampling image acquired by the processing shown in S103. Then, when it is determined that the image is captured, the target image generation unit 66 may generate a target image based on the high-speed sampling image.

Further, in the present embodiment, it is not necessary to determine the degree of decrease in air pressure based on the comparison result of the deformation amounts d of the four tires.

For example, when the value indicating the amount of curvature c specified based on the target image is larger than the predetermined value, it may be determined that the air pressure of the tire shown in the target image is reduced.

Further, for example, when the value indicating the side profile p specified based on the target image satisfies a predetermined condition, it may be determined that the air pressure of the tire shown in the target image is reduced. For example, when the dispersion of the depth for each pixel in the side surface region 50 is larger than a predetermined value, it may be determined that the air pressure of the tire shown in the target image including the side surface region 50 is reduced.

The present invention is not limited to the above-described embodiment.

Further, the above-mentioned specific numerical values and character strings, as well as specific numerical values and character strings in the drawings are examples, and the present invention is not limited to these numerical values and character strings.

10 Tire pressure drop judgment device, 12 Processor, 14 Storage unit, 16 Communication unit, 18 Display unit, 20 Operation unit, 22, 22a, 22b Imaging unit, 30 Vehicles, 32 Tollhouse gate, 34 Right front wheel, 36 Right rear Wheel, 38 Left front wheel, 40 Left rear wheel, 42 Target area, 44 Wheel, 46 Upper area, 48 Lower area, 50 Side area, 60 Detection unit, 62 Imaging control unit, 64 Imaging image acquisition unit, 66 Target image generation unit , 68 Deformation amount identification unit, 70 Pneumatic pressure drop determination unit.

Claims (10)

A photographed image acquisition means for acquiring a photographed image which is a depth image or a three-dimensional image showing the side surface of a tire provided in a vehicle, and
Deformation amount specifying means for specifying the deformation amount of the tire based on the captured image, and
A determination means for determining the degree of decrease in tire pressure based on the amount of deformation, and
A tire pressure drop determination device comprising. Further including a detecting means for detecting the presence of the vehicle in the photographing range,
The captured image acquisition means acquires the captured image captured in response to the detection that the vehicle is in the photographing range.
The tire pressure decrease degree determining device according to claim 1. The determination means determines the degree of decrease in the air pressure of the tire based on a plurality of the photographed images continuously photographed for the tire.
The tire pressure decrease degree determining device according to claim 1 or 2. The determination means determines the degree of decrease in air pressure of the plurality of tires based on the comparison result of the amount of deformation specified for each of the plurality of tires provided in the vehicle.
The tire pressure drop degree determining device according to any one of claims 1 to 3, wherein the tire pressure drop degree determination device is characterized. Further including a target image generation means for generating a target image in which the size of the area where the wheel appears is a given size by cutting out a part of the image in which the size of the captured image is changed.
The deformation amount specifying means identifies the deformation amount of the tire based on the target image.
The tire pressure decrease degree determining device according to any one of claims 1 to 3, wherein the tire pressure drop degree determination device is characterized. Further including a target image generation means for generating a target image in which the size of the area where the wheel appears is a given size by changing the size of the image obtained by cutting out a part of the captured image.
The deformation amount specifying means identifies the deformation amount of the tire based on the target image.
The tire pressure drop degree determining device according to any one of claims 1 to 3, wherein the tire pressure drop degree determination device is characterized. The target image generation means generates the target image of the tire based on the photographed image showing the side surface of the tire for each of the plurality of tires included in the vehicle.
The determination means determines the degree of decrease in air pressure of the plurality of tires based on the comparison result of the amount of deformation specified based on the target image of the tire for each of the plurality of tires.
The tire pressure drop degree determining device according to claim 5 or 6, wherein the tire pressure drop degree is determined. The deformation amount specifying means indicates at least one of the height of the tire, the amount of curvature of the side surface of the tire, or the distribution of the distance from the position where the photographed image is taken to the surface of the tire. Identify the amount of deformation,
The tire pressure decrease degree determining device according to any one of claims 1 to 7, wherein the tire pressure drop degree determination device is characterized. The step of acquiring a captured image which is a depth image or a three-dimensional image showing the side surface of the tire provided in the vehicle,
A step of specifying the amount of deformation of the tire based on the captured image, and
A step of determining the degree of decrease in tire pressure based on the amount of deformation, and
A method for determining the degree of decrease in tire pressure, which comprises. Procedure for acquiring a captured image which is a depth image or a three-dimensional image showing the side surface of a tire provided in a vehicle,
A procedure for identifying the amount of deformation of the tire based on the captured image,
A procedure for determining the degree of decrease in tire pressure based on the amount of deformation,
A program characterized by having a computer execute.

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