JP4322652B2 - Tire contact image analysis method, tire contact image analysis apparatus, and tire contact image analysis program - Google Patents

Description

  The present invention relates to a tire contact image analysis method, a tire contact image analysis apparatus, and a tire contact image analysis program, and more specifically, visualizes and quantifies a change in the position of a block within a contact surface of a rotating tire. The present invention relates to a tire contact image analysis method, a tire contact image analysis apparatus, and a tire contact image analysis program.

  A pneumatic tire (hereinafter simply referred to as a “tire”) is a vehicle such as a passenger car that moves on the road surface so that the vehicle comes into contact with the road surface and power from a power source such as an engine mounted on the vehicle. Is the only one that transmits to the target surface. Therefore, the performance of the tire has a great influence on the motion performance of the vehicle. The tire performance includes evaluation items such as noise performance, friction performance, cornering performance, and anti-hydroplaning performance, and these evaluation items vary depending on tire contact characteristics. The tire contact characteristics include a contact area, an average pressure based on a load and a contact area, a maximum contact length in the tire circumferential direction (contact length direction), and a maximum contact width in the tire width direction (contact width direction). In order to obtain these tire contact characteristics with high accuracy, it is important to accurately determine the tire contact shape when the tire contacts the road surface.

Conventionally, as shown in Patent Document 1, a technique for measuring a ground contact image of a tire that is not rotating and performing image analysis of the ground contact image to obtain a tire ground contact shape has been proposed. The tire ground contact image analysis apparatus shown in Patent Document 1 generates ground contact image data from the measured ground contact image, and contracts with the procedure of expanding the generated ground contact image data until it becomes one filled block. The tire ground contact shape is obtained by repeating the procedure in combination. Here, the tire mounted on the vehicle actually contacts the road surface while rotating. Therefore, as in the tire ground contact image analysis apparatus shown in Patent Document 1, the tire is rotating, that is, the vehicle is moving rather than the state where the tire is rotating, that is, the tire ground contact characteristic is obtained from the static tire ground contact shape. Obtaining the tire ground contact characteristics from the actual tire ground contact shape can accurately determine the tire ground contact characteristics of the tire that is in contact with the road surface while actually rotating. Therefore, conventionally, a technique for obtaining a dynamic tire ground contact shape as shown in Patent Document 2 has been proposed.
Japanese Patent No. 3293670 JP-A-8-233558

  However, in the tire ground contact image analyzing apparatus shown in Patent Document 2, a ground contact image at an arbitrary position in the tire circumferential direction of the rotating tire is measured, and ground contact image data is generated from the ground contact image. A dynamic tire ground contact shape is obtained from the ground contact image data. That is, the instantaneous dynamic tire ground contact shape with respect to the road surface of the rotating tire is obtained. Here, in the contact surface of the rotating tire, the shape of the block changes while changing its position in the tire rotation direction within the contact surface. For this reason, in order to accurately determine the tire ground contact characteristics of a tire that contacts the road surface while actually rotating, the block change history such as the block position change and shape change within the ground contact surface of the rotating tire is important. It becomes an element. However, with the tire ground contact image analyzing apparatus shown in Patent Document 2, it is only possible to obtain the instantaneous dynamic tire ground contact shape of the rotating tire.

  In order to confirm the change history of the block in the tire contact surface from the instantaneous dynamic tire contact shape obtained by the tire contact image analyzer shown in Patent Document 2, first, the rotating tire The ground contact image is continuously measured, ground image data is generated from the plurality of measured ground contact images, and an instantaneous dynamic tire ground contact shape is obtained from the plurality of generated ground image data. And it was necessary to confirm the change history of a block by visually observing and comparing a target block in the obtained plurality of instantaneous dynamic tire ground contact shapes. In other words, the block change history could not be visualized and quantified.

  Therefore, the present invention has been made in view of the above, and a tire contact image analysis method, a tire contact image analysis apparatus, and a tire that can visualize and quantify change histories such as block position changes and shape changes. An object is to provide a ground image analysis program.

  In order to solve the above-described problems and achieve the object, the present invention is a tire ground contact image analyzing method, wherein a ground contact image at the time of rotation of a tire having a block formed on a tread surface is continuously obtained at predetermined sampling intervals. The procedure for measuring, the procedure for generating the ground image data for each measurement time from each measured ground image, the procedure for recognizing the block in each generated ground image data, and the reference among the blocks in the ground image data at the start of measurement The procedure for selecting a block, the procedure for identifying the block corresponding to the selected reference block among the blocks in each ground image data by the overlapping of the blocks in the ground image data whose measurement times are adjacent, and the specification in each ground image data A block change image data for each measurement time from the measured block. It is characterized in.

  According to the present invention, the reference block is selected from the blocks in the ground contact surface of the tire, and the blocks corresponding to the reference block in the ground contact surface of the tire at each measurement time are selected in the ground image data adjacent in the measurement time. The block change image data for each measurement time is generated from the specified block by specifying the block overlap. Therefore, the created block change image data becomes image data of the reference block at each measurement time when the position, shape, and the like change within the tire contact surface when the tire rotates. Thus, by creating block change image data, it is possible to visualize and quantify change histories such as block position changes and shape changes.

  In the present invention, the tire ground contact image analysis method further includes a procedure of creating overlap change history image data obtained by superimposing block change image data for each measurement time.

  According to the present invention, the tire ground contact image analysis method further includes a step of creating a composite group change history image data by generating an outline of a block group corresponding to a reference block that overlaps the overlap change history image data. And

  According to these inventions, since a plurality of block change image data for each measurement time is used as one overlap change history image data or composite change history image data, the ground contact surface of the tire when the tire is rotated by one image data. It is possible to easily visualize and quantify a change history such as a change in position and shape of a reference block in the inside. In addition, as the measurement time becomes longer, the total data amount of each block change image data increases, but by making a plurality of block change image data for each measurement time into one overlap change history image data or composite change history image data. The amount of data can be reduced.

Further, in the present invention, in the tire contact image analysis method, the predetermined sampling interval is such that the minimum block length in the tire rotation direction among the blocks on the tread surface of the tire is L [mm], and the tire measurement speed V [km / h]. ], The sampling interval D is obtained by the following equation (1).
D <0.9 × (L / 1000) / (V / 3.6) (1)

  According to the present invention, all the blocks on the tread surface of the tire overlap each other in the ground image data whose measurement times are adjacent to each other. Therefore, regardless of which block on the tread surface of the tire is selected as the reference block, the block corresponding to this reference block in the ground contact surface of the tire at each measurement time is the block between the ground image data whose measurement times are adjacent to each other. The block change image data after the measurement time can be created from the identified block.

  According to the present invention, in the tire ground contact image analysis method, when a plurality of blocks having different shapes are formed in the tire rotation direction of the tread surface of the tire, the reference block is selected for each block having a different shape. It is characterized by that.

  According to this invention, block change image data for each measurement time can be created for each block having a different shape formed in the tire rotation direction of the tread surface of the tire. Accordingly, it is possible to compare change histories such as block position changes and shape changes between blocks having different shapes from the block change image data of the blocks having different shapes.

  In the present invention, the tire contact image analysis method further includes a procedure of creating average composite change history image data obtained by averaging composite change history image data created for each block having a different shape. .

  According to the present invention, the average position change and shape change of the plurality of blocks having different shapes from the change history of the position change and shape change of the plurality of blocks having different shapes in the tire rotation direction of the tire tread surface. The change history can be visualized and quantified.

  Further, according to the present invention, in the tire ground contact image analyzing apparatus, processing means for processing each procedure in the tire ground contact image analyzing method, and input for giving data necessary for determining a predetermined sampling interval to the processing means and other data And a display means for displaying block change image data by the processing means and other image data.

  According to the present invention, the tire ground contact image analyzing apparatus includes processing means for executing the tire ground contact image analyzing method. Accordingly, the reference block is selected from the blocks in the tire contact surface, and the block corresponding to the reference block in the tire contact surface at each measurement time is determined by the overlapping of the blocks in the ground image data whose measurement times are adjacent to each other. The block change image data after the measurement time can be created from the identified block. As a result, the created block change image data becomes image data of the reference block at each measurement time in which the position and shape of the tire contact surface change as the tire rotates. Change history such as shape change can be visualized and quantified.

  The present invention is characterized in that a computer executes the tire ground contact image analysis method. According to the present invention, by causing the computer to read and execute the program, the tire ground contact image analysis method can be realized using the computer, and the same effects as those of these methods can be obtained.

  According to the tire ground contact image analysis method, the tire ground contact image analysis apparatus, and the tire ground contact image analysis program according to the present invention, the change history such as the block position change and the shape change can be visualized and quantified. The ground contact characteristics can be obtained, and the tire ground contact characteristics can improve the reliability of evaluating the tire performance.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the best mode for carrying out the invention. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

  FIG. 1 is a diagram showing a configuration example of a tire ground contact image analyzing apparatus that executes the tire ground contact image analyzing method according to the present invention. The tire ground contact image analyzing apparatus 1 includes an imaging device 2 and an image processing device 3. The imaging device 2 includes a sheet-like medium 2a, a support substrate 2b, and a camera 2c, and measures a ground image of the tread surface T1 of the tire T and generates ground image data from the measured ground image. It is.

  The sheet-like medium 2a is placed on the support substrate 2b, and the tire 1 is moved in the direction of A in FIG. 1, that is, the tire rotation direction by a driving device (not shown), and has a certain thickness and a certain length. Cardboard, paper, or other suitable sheet. That is, the tire 1 rotates in the tire rotation direction A, and the sheet-like medium 2a also moves in the tire rotation direction A. The support substrate 2b is formed of a tempered glass that supports the tire 1 with a predetermined load and has transparency. The camera 2c is, for example, a CCD camera or the like, and captures a grounding image of the tire 1 with respect to the support substrate 2b through the sheet-like medium 2a by applying light from an illumination lamp (not shown) from the back surface of the support substrate 2b. . Further, the imaging timing of the camera 2c, that is, the sampling interval is calculated by a processing unit 3b described later of the image processing apparatus 3, and the camera 2c is connected to the tire by an imaging signal output from the processing unit 3b at each calculated sampling interval. A ground image of the tread surface Ta of T is taken. The camera 2c is obtained by applying a transfer material such as black ink or vermilion to the tread surface 1a of the tire 1 in advance without using the sheet medium 2a and the support substrate 2b, and transferring the transfer material to a transfer material such as paper. A ground contact image of the tire 1 may be taken.

  Here, the camera 2c A / D converts the captured ground image of the tread surface Ta of the tire T from an analog state to a digital state, that is, ground image data. Here, the converted ground image data is pixel data such as a pixel image. If the ground image data is captured in color by the camera 2c, the ground image data is color image data. When the ground image data is color image data, each pixel has an RGB value. The ground image data is not limited to color image data, and may be either binary image data or gray scale image data.

  The image processing apparatus 3 includes a storage unit 3a and a processing unit 3b that are processing means. An input / output device 4 is connected to the image processing device 3, and an input unit 4 a provided therein includes a tire measurement speed described later, the type of the imaged tire T, the grounding condition of the tire T, and the like. The other data is also given to the storage unit 3a and the processing unit 3b. Here, the imaging device 2 and the image processing device 3 may be connected directly or indirectly. That is, the ground image data generated by the imaging device 2 is directly transmitted to the storage unit 3a and the processing unit 3b of the image processing device 3 via a data transmission / reception cable (not shown) that connects the imaging device 2 and the image processing device 3. You may enter. Further, the ground image data of the tire T imaged and generated at another location is stored in a recording medium (not shown) from the imaging device 2, and the ground image data stored in the recording medium is indirectly stored in the image processing device 3. You may indirectly input into the memory | storage part 3a and the process part 3b. Here, input devices such as a keyboard, a mouse, and a microphone can be used as the input means 4a.

  The storage unit 3a stores a tire contact image analysis program in which the tire contact image analysis method of the present invention for realizing the tire contact image analysis method of the present invention is incorporated. Here, the storage unit 3a is a fixed disk device such as a hard disk device, a flexible disk, a magneto-optical disk device, or a non-volatile memory such as a flash memory (a storage medium that can only be read such as a CD-ROM), It can be constituted by storage means such as a volatile memory such as RAM (Random Access Memory), or a combination thereof.

  The tire ground contact image analysis program is not necessarily limited to a single configuration, but cooperates with a program already stored in a computer system, for example, a separate program represented by an OS (Operating System). It is also possible to achieve this function. Further, a tire ground contact image analysis program for realizing the function of the processing unit 3b shown in FIG. 1 is stored in a computer-readable recording medium, and the tire ground contact image analysis program recorded on the recording medium is read into a computer system. The tire ground contact image analysis method according to the present invention may be executed by executing the method. The “computer system” here includes an OS and hardware such as peripheral devices.

  The processing unit 3b includes a memory such as a RAM and a ROM, and a CPU (Central Processing Unit). At the time of tire ground contact image analysis, based on the ground contact image data input to the image processing device 3 as described above, the processing unit 3b reads the tire ground contact image analysis program into a memory (not shown) of the processing unit 3b. Perform the operation. Note that the processing unit 3b appropriately stores a numerical value in the middle of the calculation in the storage unit 3a, and appropriately calculates the stored numerical value from the storage unit 3a. The processing unit 3b may be realized by dedicated hardware instead of the tire ground contact image analysis program.

  The block change image data created by the calculation by the processing unit 3b is displayed by the display unit 4b of the input / output device 4. Here, a CRT (Cathode Ray Tube), a liquid crystal display device, or the like can be used as the display means 4b. The created block change history image data and the like can be output to a printer (not shown). The storage unit 3a may be provided in the processing unit 3b, or may be provided in another device (for example, a database server). Moreover, the structure which can access the image processing apparatus 3 by the wired or wireless method from the terminal device which is not shown provided with the input / output device 4 may be sufficient.

  Next, a tire ground contact image analysis method will be described. Here, a case where a block change history is obtained will be described. Here, the block refers to a land portion that is partitioned by a groove and is closed in the ground contact surface of the tire T. Therefore, a portion defined by sipes (thin grooves) is also included in the block.

FIG. 2 is a view showing a flowchart of the tire ground contact image analyzing method according to the present invention. FIG. 3 is a diagram illustrating a flowchart of a method for continuously measuring a ground contact image during tire rotation. 4A to 12 are diagrams illustrating the generated ground image data for each measurement time.
5A and 5B are explanatory diagrams of a method for selecting a reference block. FIG. 6 is a flowchart illustrating a method for identifying a block corresponding to a selected reference block. FIGS. 7A to 7 are explanatory diagrams of a method for specifying a block corresponding to the selected reference block. FIGS. 8-1 to 12 are diagrams showing block change image data created for each measurement time. FIG. 9A is a diagram illustrating the created overlap change history image data. FIG. 9B is a diagram illustrating the created composite change history image data.

First, as shown in FIG. 2, in the tire ground contact image analyzing method according to the present invention, first, a ground contact image during tire rotation is continuously measured at a predetermined sampling interval (step ST1). Specifically, as shown in FIG. 3, first, among the blocks formed on the tread surface T1 of the tire T from the input means 4a of the input / output device 4, the minimum block length L [mm] in the tire rotation direction and The measurement speed V [km / h] of the tire T that is rotated by a drive device (not shown) is input to the image processing device 3 (step ST101). Next, the processing unit 3b calculates the following formula (2) based on the minimum block length L [mm] and the measurement speed V [km / h] to which the sampling interval D [sec] is input ( Step ST102). Here, the minimum block length L [mm] is the length in the tire rotation direction of the block having the minimum length in the tire rotation direction among the land portions partitioned by the grooves on the tread surface T1 of the tire T. It is.
D <0.9 × (L / 1000) / (V / 3.6) (2)

When the processing unit 3b determines the sampling interval D [sec] as described above, all the blocks on the tread surface T1 of the tire T are overlapped with each other in the ground image data adjacent to each other in the measurement time described later. The sampling interval D [sec] is preferably calculated so as to satisfy the following formula (3). This is because the tread surface T1 of the tire T has a minimum block length L [mm] in the tire rotation direction A every sampling interval D [sec], assuming that the sampling interval D [sec] is maximum in the above equation (2). ], The overlap of the contact surface of the tire T at the adjacent measurement time is about 10%. However, when the shape of the block formed on the tread surface T1 of the tire T is complicated, there is a possibility that this block does not overlap in the ground contact surface of the tire T at the adjacent measurement time. Therefore, when the sampling interval D [sec] is maximized using the following formula (3) having a short sampling interval D [sec], the tread surface T1 of the tire T is in the tire rotation direction A and the minimum block length L [mm] ], The overlap of the contact surface of the tire T at the adjacent measurement time is about 50%. Thereby, even if the shape of the block formed on the tread surface T1 of the tire T is complicated, the blocks can be reliably overlapped in the ground contact surface of the tire T at the adjacent measurement time.
D <0.5 × (L / 1000) / (V / 3.6) (3)

  Next, the tire T is rotated in the tire rotation direction A by a driving device (not shown), and the processing unit 3b outputs an imaging signal to the imaging device 2 at each sampling interval D (step ST103). Next, the camera 2c of the imaging device 2 continuously captures the ground contact image of the rotating tire T using the imaging signal, that is, continuously measures every measurement time based on the sampling interval D (step ST104). .

Next, as shown in FIG. 2, ground image data for each measurement time is generated from each ground image (step ST2). This camera 2c of measuring the ground image of the tire T converts the ground image is an analog state into a ground image data is a digital state, and generates a ground image data 10 ₁ ~ _n. For example, the processing unit 3b outputs the 12 times the imaging signal to the camera 2c of the imaging apparatus 2 to the image pickup apparatus 2 based on the sampling interval, as shown in FIG 4-1～12 twelve ground image data 10 ₁ ~ ₁₂ is generated. As shown in the figure, the position of the block in the contact surface of the tire T changes within the contact surface while changing its shape every measurement time. The generated ground image data 10 ₁ to _n are output from the imaging device 2 to the image processing device 3, and the input ground image data 10 ₁ to _n are temporarily stored in the storage unit.

Next, as shown in FIG. 2, a block in each generated ground image data is recognized (step ST3). Specifically, the first processing unit 3b, reads each ground image data 10 ₁ ~ _n which is stored in the storage unit, the noise removal and edge portions of the ground image data 10 ₁ ~ _n optionally filling Etc. As shown in FIGS. 5A and 5B, the closed area is recognized in each of the ground image data 10 ₁ to _n , and a labeling process for adding a label to the closed area is performed. recognizing the blocks in each ground image data 10 ₁ ~ _n was. When the generated ground image data 10 ₁ to _n is color or gray scale image data, at least before each block of the generated ground image data 10 ₁ to _n is recognized, each pixel is binarized. It is preferable to convert it into converted image data. This is in recognizing the blocks in each ground image data 10 ₁ ~ _n which is the image data of the color or gray scale, must determine the threshold, the determination of this threshold, the recognized block This is because the shape may be different from the shape of the block in the actual contact surface of the tire T.

Next, as shown in FIG. 2, a reference block is selected from the blocks recognized in the ground image data at the start of measurement (step ST4). More specifically, first processing unit 3b is ground image data 10 ₁ measurement start, which is the recognition of the block shown in Figure 5-1 towards the tire rotation direction, the scanning in the tire width direction from the upper end to the lower end To do. By this scanning, among the recognized block 20 ₁ shown in the figure, as shown in Figure 5-2, the reference block 21 to block an area closed in the vicinity ground front end of the tire T in the tire width direction select. That is, the selected reference block 21 is the block 21a that is first recognized by the above scanning among the block group defined by the grooves (circumferential grooves) formed in the tire rotation direction of the tread surface T1 of the tire T. ~ E. As a block change image data 30 ₁ created image data of the reference block 21 is selected, temporarily stored in the storage unit 3a. In the case of selecting a reference block 21 one of any block of the block 20 ₁ which are recognized in the ground image data 10 ₁ at the start of measurement, first, the processing unit 3b is previously measured at the start of the ground image It recognizes the blocks demarcated by the grooves formed in the tire rotation direction of the tread surface T1 of the tire T in the data 10 ₁ (circumferential groove). Then, only the block group including the block to be selected as the reference block 21 is scanned, and the block recognized first by this scanning is selected as the reference block.

Next, as shown in FIG. 2, the block corresponding to the selected reference block among the blocks in each installation image data is specified by the overlapping of the blocks in the ground image data whose measurement times are adjacent to each other. Block change image data is created (step ST5). Specifically, as shown in FIG. 6, first, the process unit 3b reads out the block change image data 30 ₁ which is the image data of the reference block 21 stored in the storage unit, the reference shown in Figure 7-1 block 20 ₂ time measurement and the ground image data 10 ₁ measurement at the start of the selected block is adjacent read the recognized grounded image data 10 ₂ (step ST 501). Next, as illustrated in FIG. 7B, the processing unit 3b uses the block change image data 30 ₁ that is the read image data of the reference block 21 and the ground image data 10 ₂ in which the block 20 ₂ is recognized. Overlay (step ST502). Next, the processing unit 3b calculates a logical product of the superimposed reference block 21 and all the blocks 20 ₂ recognized in the ground image data 10 ₂ (step ST503). Next, the processing unit 3b identifies the block 22 that overlaps the reference block 21 in which the calculated logical product is not 0 as the block 22 corresponding to the reference block 21 (step ST504). Next, the processing unit 3b creates block change image data 30 ₂ from the identified block 22 (step ST505). That is, the block changed image data 30 ₂ created the image data of the block 22 identified, temporarily stored in the storage unit 3a. As shown in FIGS. 7-2 and 7-3, when the reference block 21 is a plurality of blocks 21a to 21e, the blocks 22a to 22a to which the logical product is not 0 with the blocks 21a to 21e which are the reference blocks 21, respectively. Let e be the identified block 22.

Then, the processing unit 3b judges whether or not to create all the block change the image data 30 ₁ ~ _n which corresponds to the ground image data 10 ₁ ~ _n (step ST 506). That is, it is determined whether or not the block corresponding to the reference block 21 is identified from the blocks recognized in the ground image data 10 ₁ to _n among all the ground image data 10 ₁ to _n . When the block change image data 30 ₁ to _n corresponding to all the ground image data 10 ₁ to _n are not created, steps ST501 to ST505 are repeated. Specifically, the processing unit 3b includes block change image data 30 ₂ that is image data of the block 22 corresponding to the reference block 21 stored in the storage unit 3a, and the ground image data 10 in which the block 22 is specified. _The block recognized in the ground image data 10 ₃ adjacent to the measurement time ₂ is read (step ST501). Next, the processing unit 3b superimposes the block change image data 30 ₂ that is the image data of the read block 22 and the block recognized in the ground image data 10 ₃ (step ST502). Next, the processing unit 3b calculates a logical product of the identified block 22 and all the blocks recognized in the ground image data 10 ₃ (step ST503). Next, the processing unit 3b identifies a block that overlaps the block 22 corresponding to the reference block 21 whose calculated logical product is not 0 as a block corresponding to the reference block 21 (step ST504). Next, the processing unit 3b creates block change image data 30 ₂ from the identified block 22 (step ST505). That is, the block changed image data 30 ₂ created the image data of the block 22 identified, temporarily stored in the storage unit 3a. Thereby, the block change images 30 ₁ to _n for each measurement time can be created from the specified blocks (including the reference block) in each of the ground contact image data 10 ₁ to _n . For example, as shown in FIGS. 8A to 12, twelve block change image data 30 ₁ to ₁₂ are generated.

As described above, the generated block change image data 30 ₁ to _n are the image data of the reference block 21 at each measurement time when the position, shape, and the like change in the contact surface of the tire T when the tire T rotates. Become. Therefore, by creating a block change image data 30 ₁ ~ _n, it is possible to visualize, quantify the change history such as the position change and the shape change of the block. In steps ST503 and 504, the logical product is used when specifying the block that overlaps the reference block 21 or the block corresponding to the reference block 21, but the present invention is not limited to this. For example, the processing unit 3b first calculates the center of gravity of the block recognized in the ground image data 10 _n adjacent to the reference block 21 or the block corresponding to the reference block 21 and the measurement time. Then, the block recognized in the ground image data 10 _n having the measurement time having the centroid closest to the centroid of the reference block 21 or the block corresponding to the reference block 21 is made to correspond to the reference block 21. May be. Further, the processing unit 3b first calculates the contour line of the block recognized in the ground image data 10 _n adjacent to the reference block 21 or the block corresponding to the reference block 21 and the measurement time. Then, the block recognized in the ground image data 10 _n having the measurement time adjacent to the reference block 21 or the outline of the block corresponding to the reference block 21 is set as the block corresponding to the reference block 21. Also good.

Next, as shown in FIG. 2, overlap change history image data is created by superimposing the block change image data 30 ₁ to _n for each measurement time (step ST6). Specifically, first, the processing unit 3b reads the block change image data 30 ₁ to _n for each measurement time stored in the storage unit 3a, and reads the block change image data 30 ₁ to _n for each read measurement time. Overlap, one overlap change history image data 40 as shown in FIG. The created overlap change history image data 40 is stored in the storage unit 3a.

  Next, as shown in FIG. 2, the outline of the block group corresponding to the overlapping reference block of the overlapping change history image data 40 is generated to create the combined change history screen data 50 (step ST7). Specifically, the processing unit 3b first reads the overlap change history image data 40 stored in the storage unit 3a, and a block group 41 corresponding to the reference block 21 overlapping in the read overlap change history image data 40. Is generated, one composite change history image data 50 as shown in FIG. 9-2 is created. The created composite change history image data 50 is stored in the storage unit 3a. In the generation of the contour line, the contour lines of the blocks corresponding to the reference block 21 are averaged, or the maximum value or the minimum value in the tire rotation direction and the tire width direction is obtained from the contour lines of the blocks corresponding to the reference block. To generate.

As described above, since the overlap change history image data 40 or the composite change history image data 50, which is one image data, is created from the plurality of block change image data 30 ₁ to _n for each measurement time, the tire is formed from one image data. It is possible to easily visualize and quantify a change history such as a change in position and shape of the reference block 21 in the contact surface of the tire T when T rotates. In addition, as the measurement time increases, the amount of data of the block change image data 30 ₁ to _n increases, but a plurality of block change image data 30 ₁ to _n for each measurement time is combined into one overlapping change history image data 40 or By using the combined change history image data 50, the amount of data can be reduced.

  In the best mode for carrying out the invention, the case where one of the blocks continuous in the tire rotation direction of the tread surface T1 of the tire T is selected as the reference block 21 has been described. There are cases where a plurality of blocks having different shapes are formed in the tire rotating direction of the tread surface T1 of the tire T for the purpose of improving the above. In this case, the selection of the reference block 21 in step ST4 shown in FIG. 2 is performed for all the blocks having different shapes. Thereby, the block change image data for every measurement time can be created for each block having a different shape formed in the tire rotation direction of the tread surface T1 of the tire T. Accordingly, it is possible to compare change histories such as block position changes and shape changes between blocks having different shapes from the block change image data of the blocks having different shapes.

Here, as a method of selecting a reference block for each block having different shapes, first, by executing the steps shown in FIG. 2, arbitrary blocks among blocks having different shapes in the tire rotation direction of the tread surface T1 of the tire T are arbitrarily selected. Are selected as the reference block 21, and block change image data 30 ₁ to _n for each measurement time are created. Next, the rotation start position of the tire T with respect to the imaging device 2 is changed so that an arbitrary block desired to be the reference block 21 and a block having a different shape are present in the ground image data 10 ′ ₁ to _n at the start of measurement. , by performing the steps shown in the figure, may be created block change image data 30' ₁ ~ _n of each measurement time corresponding to the ground image data 10' ₁ ~ _n.

Alternatively, first, the ground image data 10 _n is generated in advance until a measurement time in which an arbitrary block selected as the reference block 21 does not already exist among the blocks having different shapes in the tire rotation direction of the tread surface T1 of the tire T. Next, by executing each step shown in FIG. 2, an arbitrary block is selected as the reference block 21 among the blocks having different shapes in the tire rotation direction of the tread surface T1 of the tire T, and a block change image for each measurement time. Data 30 ₁ to _n are created. Next, all the ground image data 10 ′ ₁ to _{n in} which an arbitrary block desired to be the reference block 21 and a block having a different shape exist are selected. Then, drawing on the show perform step may create blocks change image data 30' ₁ ~ _n of each measurement time corresponding to the ground image data 10' ₁ ~ _n this selected.

  Note that, as described above, block change image data for each measurement time is created for each block having a different shape formed in the tire rotation direction of the tread surface T1 of the tire T, and an overlapping change history image is created for each block having a different shape. When the data and composite change history image data are created, average composite change history image data may be created by averaging the composite change history image data for each of the created blocks having different shapes. As a result, the average position change and shape change of the plurality of blocks having different shapes from the change history of the position change and shape change of the plurality of blocks having different shapes in the tire rotation direction of the tread surface T1 of the tire T. The history can be visualized and quantified.

  Here, the above-described composite change history image data was compared with conventional instantaneous dynamic tire contact image data by the tire contact image analysis method. 10-1 and 11-1 are diagrams showing conventional instantaneous dynamic tire ground contact image data. FIGS. 10-2 and 11-2 are views showing the created composite change history image data. Here, the tire to be measured in FIGS. 10-1 and 2 has a tire inner pressure of 200 kPa, a load of 3400 N, a slip, with a radial tire for a passenger car having a size of 195 / 60R14 85H mounted on a rim (not shown). The angle was measured as 1.0 °. On the other hand, the tires to be measured in FIGS. 11-1 and 11 are measured with a tire inner pressure of 230 kPa and a load of 4800 N with a radial tire for a passenger car having a size of 225 / 50R16 mounted on a rim (not shown). It is.

  Compared with the conventional instantaneous dynamic tire ground contact image data 100 shown in FIG. 10-1, the composite change history image data 101 shown in FIG. 10-2 shows the block position change and shape change in the contact surface. Visualization and quantification are possible. Further, in comparison with the conventional instantaneous dynamic tire ground contact image data 110 shown in FIG. 11-1, the composite change history image data 111 shown in FIG. 11-2 is a block position change and shape within the contact surface. Changes can be visualized and quantified. Accordingly, tire contact characteristics (contact area, average pressure, maximum contact length, maximum contact width, etc.) can be accurately calculated based on the composite change history images 101 and 111. Moreover, the reliability of the tire 1 performance evaluation (noise performance, friction performance, cornering performance, hydroplaning resistance, etc.) can be improved from the tire contact characteristics with good accuracy.

  As described above, the tire ground contact image analysis method, the tire ground contact image analysis apparatus, and the tire ground contact image analysis program according to the present invention are useful for obtaining the tire ground contact characteristics, and in particular, the contact in a state where the tire is rotating. Visualizing and quantifying changes in the position of blocks on the ground, etc., it is suitable for determining the tire ground contact characteristics of a rotating tire.

It is a figure which shows the structural example of the tire contact image analysis apparatus which performs the tire contact image analysis method concerning this invention. It is a figure which shows the flowchart of the tire contact image analysis method concerning this invention. It is a figure which shows the flowchart of the method of measuring the ground contact image at the time of rotation of a tire continuously. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is a figure which shows the earthing | grounding image data for every produced | generated measurement time. It is explanatory drawing of the method of selecting a reference | standard block. It is explanatory drawing of the method of selecting a reference | standard block. It is a figure which shows the flowchart of the method of specifying the block corresponding to the selected reference | standard block. It is explanatory drawing of the method of specifying the block corresponding to the selected reference | standard block. It is explanatory drawing of the method of specifying the block corresponding to the selected reference | standard block. It is explanatory drawing of the method of specifying the block corresponding to the selected reference | standard block. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the block change image data for every produced measurement time. It is a figure which shows the produced overlap change log image data. It is a figure which shows the produced synthetic change log | history image data. It is a figure which shows the conventional instantaneous dynamic tire contact image data. It is a figure which shows the produced synthetic change log | history image data. It is a figure which shows the conventional instantaneous dynamic tire contact image data. It is a figure which shows the produced synthetic change log | history image data.

Explanation of symbols

1 tire contact image analyzer 2 imaging apparatus 3 image processing apparatus 4 and out color device 10 _1-12 2-dimensional image data generating unit 20 _1, 20 ₂ recognized block 22 corresponding to the reference block blocks 30 ₁ to ₁₂ block change image Data 40 Overlap change history image data 50 Composite change history image data 100, 110 Instantaneous dynamic tire ground contact image data 101, 111 Composite change history image data

Claims (8)

A procedure for continuously measuring a ground contact image during rotation of a tire having a block formed on a tread surface at a predetermined sampling interval;
A procedure for generating ground image data for each measurement time from each measured ground image,
Recognizing a block in each generated ground image data;
A procedure for selecting a reference block among the blocks in the ground image data at the start of measurement,
A step of identifying a block corresponding to the selected reference block among blocks in each ground image data by overlapping of the blocks in the ground image data adjacent to each other in the measurement time;
Creating block change image data for each measurement time from the identified block in each ground contact image data;
A tire ground contact image analysis method comprising:   The tire ground contact image analysis method according to claim 1, further comprising a procedure of creating overlapping change history image data obtained by superimposing block change image data for each measurement time.   3. The tire ground contact image analysis according to claim 2, further comprising generating a contour line of a block group corresponding to the reference block with which the overlap change history image data overlaps to create composite change history image data. 4. Method. The predetermined sampling interval is obtained by the following equation when the minimum block length in the tire rotation direction among the blocks on the tread surface of the tire is L [mm] and the measurement speed V [km / h] of the tire. The tire contact image analysis method according to any one of claims 1 to 3, wherein the sampling interval D is determined.
D <0.9 × (L / 1000) / (V / 3.6) When a plurality of blocks having different shapes in the tire rotation direction of the tread surface of the tire are formed,
The tire ground contact image analysis method according to any one of claims 1 to 4, wherein the reference block is selected for each block having a different shape.   6. The tire ground contact image analysis method according to claim 5, further comprising a procedure of creating average composite change history image data obtained by averaging composite change history image data created for each block having different shapes. Processing means for processing each procedure in the tire ground contact image analysis method according to any one of claims 1 to 6,
Input means for giving the processing means data necessary for determining the predetermined sampling interval, and other data;
Display means for displaying block change image data and other image data by the processing means;
A tire ground contact image analyzing apparatus comprising:   A tire ground contact image analysis program that causes a computer to execute the tire ground contact image analysis method according to any one of claims 1 to 6.

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