JP6074284B2 - Method and apparatus for measuring shape of belt-like rubber member - Google Patents

Description

  The present invention relates to a shape measuring method and a shape measuring apparatus for an object to be measured such as a belt-shaped rubber member, and in particular, a shape measuring method and a shape measuring apparatus for measuring a cross-sectional shape of a belt-shaped rubber member formed continuously in a long shape. It is about.

  Conventionally, an outer shape of a tread produced as a belt-like rubber member by extrusion molding is inspected by online inspection. In the on-line inspection, the tread that has been extruded is irradiated with plane light consisting of a slit-shaped laser of a certain length so as to cross the tread in the width direction from one irradiation means, and the trace of light irradiated with the plane light Is taken with a camera to acquire the contour line of the cross-sectional shape in the width direction of the tread, import it into the image processing device, and after processing the software so that it becomes the actual cross-sectional shape of the tread by the software in the image processing device, It is determined whether the shape of the tread after molding is good or not by determining whether or not the cross-sectional shape is within an acceptable standard.

JP 2006-337270 A

However, since the slit-shaped plane light irradiated from one irradiation means is irradiated on the tread so as to spread out, the intensity of the light irradiated on the end side of the plane light tends to be weak. For this reason, in the vicinity of the shoulder portion which is the end portion of the tire tread, the contrast value between the portion irradiated with the plane light and the portion not irradiated is likely to be low, and the contour of the shoulder portion is not clear, so the cross-sectional shape of the tread It was difficult to specify the contour.
Further, on the upper side of the tread surface on which a tread pattern composed of a plurality of circumferential grooves or the like is formed, a marker line or the like indicating the center in the width direction of the tread is applied extending in the longitudinal direction. Since the reflected light of the plane light is irregularly reflected on the coating film, the cross-sectional shape may not be accurately obtained in the image. A pair of minute projections extending in the longitudinal direction of the tread are formed in the region where the marker line is applied, and the marker line is applied in a recess (groove) surrounded by the pair of projections. The minute protrusions cause irregular reflection of plane light when taking an image and hinder acquisition of a cross-sectional shape near the center of the tread, and become a factor that degrades accuracy when detecting the center position in the width direction of the tread. Yes.
Furthermore, since the molded tire tread is a rubber member, the reflectivity of the plane light differs depending on the surface part, and the contour line in the photographed image will be photographed unclearly or clearly, resulting in unclearness. In some cases, it is detected that there is an abnormality even if there is no abnormality in the actual cross-sectional shape.

  The present invention has been made in view of the above problems, and provides a shape measuring method and a shape measuring apparatus for accurately measuring the cross-sectional shape of a belt-like rubber member.

As a form of the measurement method for measuring the cross-sectional shape of the measurement object for solving the above-described problem, the surface of the measurement object is irradiated with slit light, and the irradiated portion is different from the optical axis of the slit light A shape measuring method of a belt-like rubber member for measuring a cross-sectional shape of a measurement target object by scanning the measurement target object in the length direction while acquiring image data by photographing from the direction, and is a predetermined measurement data constituting the image data A luminance value detection step for detecting the maximum luminance value and the minimum luminance value for each region of the range, and a luminance centroid position setting step for setting the luminance centroid position for the luminance value in the region detected by the luminance value detection step for each region When, and a cross-sectional shape obtaining step of obtaining a cross-sectional shape by connecting the luminance center position adjacent to each other which is Ri設 constant by the luminance gravity center position setting step, the luminance value detection step, the maximum luminance of each detected regions And the minimum luminance value is calculated, and when the contrast value is equal to or lower than a predetermined threshold value, the image data acquired at the previous time is added to the image data being processed at the previous time. value that was so that to process so that the above predetermined threshold value, the image data is even unclear can measure the cross-sectional shape of the high precision measurement object. That is, by detecting a predetermined luminance value in the area of the image data and setting the center of gravity position of the area based on the detected luminance value, even if the luminance value is different for each area, the luminance value of each area is set. Since the centroid value is calculated based on the centroid value, the cross-sectional shape can be measured with high accuracy by connecting the centroid value that is brightest in each region . Also, since the luminance value of a portion taken blurred in images data increases, it is possible to the contrast value above the threshold, the cross-sectional shape taken in the image data can be clarified.
Further, as another form of the measuring method for measuring the cross-sectional shape of the measurement target object for solving the above-mentioned problem, a high-quality tread member is supplied in the tire manufacturing process by using the measurement target object as a tire tread. can do.
Further, as a configuration of a measuring apparatus for measuring the cross-sectional shape of the measurement target object for solving the above-mentioned problem, the surface of the measurement target object is irradiated with slit light, and the irradiated part is the optical axis of the slit light. An apparatus for measuring the shape of a belt-like rubber member that measures the cross-sectional shape of an object to be measured by scanning the object to be measured in the length direction while acquiring image data by photographing from different directions, and constitutes image data Luminance value detecting means for detecting the maximum luminance value and the minimum luminance value for each area in the predetermined range, and luminance centroid position setting for setting the luminance centroid position for the luminance value in the area detected by the luminance value detecting means for each area and means, and a sectional shape acquiring means for acquiring cross-sectional shape by connecting the luminance center position adjacent to each other which is Ri設 constant by the luminance gravity center position setting unit, the luminance value detecting means, the maximum of each region detected Brightness The contrast value between the value and the minimum brightness value is calculated, and when the contrast value is equal to or less than a predetermined threshold value, the image data acquired immediately before is added to the image data currently being processed. the Rukoto be processed so that the contrast value is equal to or greater than a predetermined threshold value, even images captured in the image data is a blurred can measure the cross-sectional shape of the high precision measurement object. That is, by detecting a predetermined luminance value in the area of the image data and setting the center of gravity position of the area based on the detected luminance value, even if the luminance value is different for each area, the luminance value of each area is set. Since the centroid value is calculated based on the centroid value, the cross-sectional shape can be measured with high accuracy by connecting the centroid value that is brightest in each region.

It is a figure which shows the shape measuring apparatus which concerns on embodiment of this invention. It is a figure which shows the irradiation range of a light projector. It is a figure which shows the image data image | photographed by each imaging means. It is the elements on larger scale which show the edge part vicinity of the upper left image data. It is the elements on larger scale which expanded the upper center of image data. It is a figure which shows the cross-sectional shape which synthesize | combined the upper image data. It is a figure which shows the quality determination of the synthesized image data. It is a flowchart of the image processing by an inspection process means.

  Hereinafter, the present invention will be described in detail through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are included in the invention. It is not necessarily essential to the solution, but includes a configuration that is selectively adopted.

FIG. 1 is a schematic configuration diagram showing an embodiment of a shape measuring apparatus 1 that executes the shape measuring method for a belt-like rubber member according to the present invention.
As shown in the figure, in the present embodiment, the shape measuring device 1 is positioned on the conveyance path of an unillustrated extrusion molding machine that forms a tread T as a member constituting a tire into a long strip shape. It is conveyed in the acquisition means 2 direction. In the present embodiment, the tread T is described as an object to be measured.
The shape measuring device 1 generally includes a shape acquisition unit 2 for acquiring the shape of the extruded tread T, and the quality of the shape of the tread T formed by processing the image acquired by the shape acquisition unit 2. It is comprised with the test | inspection process means 3 to determine.

The shape acquisition unit 2 includes irradiation units 40 and 41 that irradiate the tread surface Ta with slit light, and imaging units 50 and 51 that shoot the light traces of the tread surface Ta irradiated with the slit light.
The irradiating means 40 and 41 are configured by a plurality of light projectors 4A to 4D so that light rays are irradiated over the entire outer periphery of the cross section of the tread T in the width direction. That is, in this embodiment, the upper left surface projector 4A and the upper right side projector 4B that irradiate slit light left and right on the upper surface of the tread surface Ta, and the lower surface (rear surface) slit light left and right. It comprises a lower left projector 4C and a lower right projector 4D for irradiation. As shown in FIG. 1, left and right define left and right in the transport direction.

  The upper left projector 4A, the upper right projector 4B, the lower left projector 4C, and the lower right projector 4D each direct linear slit light of a certain length, in which laser light is adjusted in a two-dimensional sheet shape, toward the tread surface Ta. Irradiate almost vertically. As shown in FIG. 2, the upper left projector 4A and the upper right projector 4B are positioned on the left and right with respect to the center mark line o extending in the longitudinal direction of the tread T, and the upper left projector 4A and the upper right projector 4B. The left and right lower projectors 4C and 4D are arranged in the longitudinal direction of the tread T so that the slit light emitted from the center marker line o protrudes beyond the center marker line o. The left half of the center marker line o is provided on the left and right with respect to the center marker line o extending to the left and right, and the slit light emitted from the lower left projector 4C and the lower right projector 4D exceeds the center marker line o, respectively. Irradiate the right half.

That is, each slit light emitted from the upper left projector 4A and the upper right projector 4B extends in the width direction of the tread T, but each slit light emitted from the lower left projector 4C and the lower right projector 4D is tread. Since it is set so that there is an overlapping range in the width direction on the upper surface side and the lower surface side of T, it is set so that the upper and lower slit lights do not line up in a straight line.
However, the slit light emitted from the upper left projector 4A and the lower left projector 4C and the slit light emitted from the upper right projector 4B and the lower right projector 4D are displaced from each other in the extending direction of the tread T. Arranged.
Thus, by arranging the projectors 4A and 4B on the upper left and right sides of the tread surface Ta and the projectors 4C and 4D on the lower left and right sides and irradiating the tread surface Ta with slit light, a uniform amount of light can be applied to the tread surface Ta. The slit light can be irradiated. That is, the slit light extending in the width direction of the tread T spreads toward the bottom and is applied to the tread surface Ta, so that the light amount on the end side is smaller than the light amount on the center side. When a portion to be irradiated with slit light is imaged by the photographing means 50 and 51 (to be described later) with the amount of light on the end side, only the portion irradiated on the end side of the slit light is unclear in the captured image data. However, as in the present embodiment, the tread surface Ta is formed on the end side of the slit light by disposing the upper side and the lower side in the width direction of the tread T like the projector 4A, the projector 4B, the projector 4C, and the projector 4D. Since it is not necessary to irradiate, clear image data can be obtained. In addition, since a plurality of projectors in the width direction of the tread T, such as the projector 4A, the projector 4B, the projector 4C, and the projector 4D, the tread surface Ta is irradiated with slit light by a single projector having the same output. Since the distances of the projector 4A and the projector 4B, the projector 4C, and the projector 4D with respect to the surface Ta can be reduced, the amount of slit light applied to the tread surface Ta is increased and a clearer sectional shape can be obtained.

The photographing means 50 and 51 are area cameras, and are provided individually corresponding to the four projectors 4A to 4D.
That is, the photographing means 50 includes a left upper photographing means 5A corresponding to the left upper projector 4A and an upper right photographing means 5B corresponding to the upper right projector 4B, and the photographing means 51 corresponds to the lower left photographing corresponding to the lower left projector 4C. Means 5C and lower right photographing means 5D corresponding to the lower right projector 4D.

Each of the photographing means 5A to 5D photographs the reflected light reflected by the tread surface Ta from a position inclined by a predetermined angle with respect to the optical axis of the slit light irradiated from the corresponding projectors 4A to 4D. The contour lines of the cross-sectional shape P of the part irradiated with the slit light are respectively acquired as Da, upper right side image data Db, lower left side image data Dc, and lower right side image data Dd. In addition, the optical axis which each imaging | photography means 5A thru | or 5D image | photographs, and the optical axis of each slit light corresponding to it are set to the same angle. In addition, the distance between the irradiated portion of the tread surface Ta of the slit light irradiated from each of the projectors 4A to 4D and the photographing means 5A to 5D is set to be equal.
In this embodiment, the front and back surfaces of the tread T are irradiated with slit light, the front and back slit lights are photographed, the outer shapes of the front and back surfaces are detected, and the cross-sectional shape is measured. In this case, by conveying the tread T, the cross-sectional shape is measured over the entire length of the tread T while scanning in the length direction of the tread T. Note that two pairs of projectors and photographing means are provided on the front and back, but this is for increasing the resolution. If necessary, one set is provided on the front and back of the tread T. The number may be set as appropriate.

As a result, the size of the cross-sectional shape P included in each of the image data Da, Db, Dc, and Dd photographed by each of the photographing means 5A to 5D as described later becomes constant, so that each of the image data Da, Db, and Dc. , Dd can be made constant, so that the synthesis accuracy when the image data Da, Db, Dc, Dd are synthesized can be improved.
That is, the optical axis photographed by each of the photographing means 5A to 5D and the corresponding optical axis of each slit light are set at the same angle, and the irradiation part of the tread surface Ta of the slit light emitted from each of the projectors 4A to 4D By setting the distances to the photographing means 5A to 5D to be equal, the size of the partial cross-sectional shape P included in each of the image data Da, Db, Dc, Dd photographed by the photographing means 5A to 5D is constant. Therefore, it is possible to improve the synthesis accuracy when synthesizing the image data with the distortion in each of the image data Da, Db, Dc, and Dd being constant.

  The image data Da, Db, Dc, Dd photographed by the photographing means 5A to 5D are individually output to the inspection processing means 3. Specifically, each of the image data Da, Db, Dc, and Dd is, as shown in FIG. 3, a partial outline Ca, Cb, Cc of the cross-sectional shape P photographed individually by each photographing means 5A to 5D. , Cd are acquired as image data Da, Db, Dc, Dd, respectively, and output to the inspection processing means 3.

  The inspection processing means 3 is a so-called computer, and includes a CPU as a calculation means, a ROM and a RAM as storage means, and an input / output interface as a communication means. The storage means stores a processing program for executing inspection processing, and image processing is performed on the image data Da, Db, Dc, Dd photographed by the photographing means 5A to 5D by executing the processing program. Then, it is inspected whether there is an abnormality as to whether or not the outer shape of the tread T is out of the range of the regular shape.

  Specifically, the inspection processing unit 3 includes an image preprocessing unit 31 that performs preprocessing of the image data Da, Db, Dc, and Dd photographed by the photographing units 5A to 5D, and preprocessed image data Da, The center position detecting means 32 for detecting the center position in the width direction of the tread from Db, Dc, Dd and the contour lines Ca, Cb, Cc, Cd of the preprocessed image data Da, Db, Dc, Dd are combined as a cross-sectional image. A cross-sectional image synthesizing unit 33, and an image comparison / determination unit 34 that compares a cross-sectional image with a master image prepared and stored in advance as a cross-sectional image comparison target.

  The image preprocessing unit 31 includes a luminance value detection unit 31a, a gravity center position detection unit 31b, and a cross-sectional shape acquisition unit 31c. The image preprocessing unit 31 scans the frame F of the image data Da, Db, Dc, Dd output from each of the photographing units 5A to 5D in the vertical direction, sets each pixel column as a predetermined area, and sets the pixel column in this pixel column. The maximum luminance value and the minimum luminance value included are detected, and the contour lines Ca, Cb, Cc, Cd of the cross-sectional shape P connecting the maximum luminance values in the horizontal direction of the frame F are detected. Since the light trace of the slit light imaged with the image data Da, Db, Dc, Dd is acquired in a blurred state with a thick width as the contour line of the cross-sectional shape P, a clear contour line approximating the actual shape Cannot be specified as. That is, since a set of a plurality of luminance values in the vertical direction of the frame F forms a contour line by continuing in the horizontal direction, the contour line of the cross-sectional shape P is thick and blurred.

  Therefore, as shown in FIG. 4A, the image preprocessing unit 31 scans the frames F of the image data Da, Db, Dc, and Dd in the vertical direction by the luminance value detection unit 31a, and performs the maximum for each pixel column. Detect the luminance value. Next, the minimum luminance value having the smallest luminance value is detected from the scanning range within a predetermined number of pixels in the vertical direction with the maximum luminance value for each pixel column as a reference. For example, the predetermined number of pixels may be set in a range of around 3 pixels. When the predetermined number of pixels is set to be large, the contrast value of the image data Da, Db, Dc, Dd with respect to the blurred contour lines Ca, Cb, Cc, Cd becomes large, and the contour lines Ca, Cb in the subsequent process. , Cc, Cd may not be clarified. Note that the horizontal axis in FIG. 4 is the length direction of the slit light (tread width direction), the vertical axis is the scan direction (tread thickness direction), and 1 mm (one block) in the frame F is Indicates a pixel.

  Next, a contrast value that is the difference between the average value of the maximum luminance values detected for each pixel column and the average value of the minimum luminance values is obtained for each pixel column. Each pixel constituting the image data is, for example, a gray scale of 256 gradations, and is set with a luminance value in the range of 0 to 255, and is darker to brighter from 0 to 255.

Next, when the contrast value is equal to or greater than the predetermined threshold value α, the maximum pixel value for each pixel column detected in each frame F is connected and set and stored as an outline of the cross-sectional shape P.
When the contrast value is smaller than the predetermined threshold value α, the image data Da, Db, Dc, Dd currently processed is overlaid with the image data taken immediately before at the same position. By combining the brightness values of the image data that is currently being processed with the brightness values of the previously captured image data, the maximum brightness value and the minimum brightness value for each pixel column are obtained again, and the maximum A contrast value that is a difference between the average value of the luminance values and the average value of the minimum luminance values is calculated. Thereby, it is possible to clarify the outline of the image frame F in which a predetermined contrast value cannot be obtained.

  Note that the image data can be overlaid in a range of 2 to 3 times, for example, so that the image data can be prevented from being overlaid in a blurred state. That is, since the tread T being conveyed meanders right and left on the conveying means and moves while moving up and down due to the vibration of the conveying means, the position of the tread T changes slightly for each photographing. Therefore, when the number of times of superimposing image data increases, the contour line of the image data photographed before the image data currently being processed is superimposed so as to be blurred with respect to the contour line of the image data being processed. As a result, the accuracy in the inspection is lowered and a reference contrast value cannot be obtained. Therefore, the original defect can be detected by setting the superimposition of the image data so as to be equal to or less than the above two to three times. For example, when the belt-like rubber member to be inspected is transported while being guided by the guide means, the position is hardly changed by the transport, and thus the number of times is not limited.

  Next, the center-of-gravity position setting unit 31b of the image preprocessing unit 31 scans the image data Da, Db, Dc, and Dd for which a predetermined contrast value is obtained for each pixel column in the vertical direction of the frame F again. As indicated by the black border in 4 (b), the center of gravity G of the luminance value for each pixel column is calculated, and the center of gravity G and the luminance value at the center of gravity G are stored as points corresponding to the actual tread surface Ta. . The center-of-gravity position G is stored as a coordinate position in the frame F, for example, an X coordinate in the right direction and an Y coordinate in the downward direction with the upper left corner of the frame F as the origin. Next, the adjacent coordinate positions set as the center of gravity by the cross-sectional shape acquisition means are linearly connected and set as the surface in the cross-sectional shape P and stored. Here, the center-of-gravity position G is a reference pixel that is set as a reference in a predetermined area constituted by a pixel row, and a virtual coordinate system centered on the reference pixel is further set, and each pixel from the reference pixel is set. The product of the distance (expressed by the number of pixels) and the luminance value at each pixel is obtained, and the product is defined as a position where the magnitude of the sum of the products with respect to the reference pixel is balanced.

  Thus, the barycentric position G of the luminance value is detected for each vertical pixel column in the frame F of the image data Da, Db, Dc, Dd, and the position is set as a point corresponding to the surface of the cross-sectional shape P. Thus, the points constituting the contour lines Ca, Cb, Cc, Cd acquired in a blurred state in the image data Da, Db, Dc, Dd are specified on an average basis for each pixel column, so that the tread surface Ta It can be specified as a contour line of a substantially true cross-sectional shape P without being affected by the difference in reflectance of the slit light.

  Next, the center position detecting means 32 detects the pair of protrusions 8 formed on the tread surface Ta from the image data Da and Db photographed by the left and upper right photographing means 5A and 5B. Specifically, the center position detecting means 32 scans along the contour lines Ca, Cb, Cc, Cd specified by the image preprocessing means 31, and based on the change in the gradient, the upper tread surface Ta. A pair of protrusions 8, 8 formed at the center of is detected.

A small window W having a predetermined size is set between the detected protrusions 8 and 8. Next, the gravity center position G of the luminance value of the pixels constituting the small window W is calculated and set as the tread center positions MA and MB.
The center marker line o indicating the center in the width direction on the tread surface Ta indicates that the projected slits 8 and 8 formed by the reflected slit light on the tread surface Ta in the image data Da, Db, Dc, and Dd as shown in FIG. Since a circular shape is photographed between them, the tread of the tread surface Ta at the contour lines Ca and Cb in the image data Da and Db is calculated by calculating the gravity center position G of the circular luminance value indicating the center marker line o. The center positions MA and MB can be specified.

  Next, as shown in FIG. 6, the center position detection means 32 includes the tread center position MA specified by the image data Da photographed by the upper left photographing means 5A and the image data photographed by the upper right photographing means 5B. By superimposing the tread center position Cb specified by Db, the image data Da and Db on the upper side of the tread surface Ta are combined to be combined with the upper combined image data. Next, the positions of the left and right ends Ea and Eb on the tread surface Ta are detected from the upper composite image data, and the half position between the ends Ea and Eb is calculated as the arithmetic center position to calculate the tread center position. It is determined whether or not it matches MA (MB).

  Next, the cross-sectional image synthesizing unit 33 detects the positions of both end portions Ec and Ed of the tread T from the image data Dc photographed by the lower left photographing unit 5C and the image data 5d photographed by the lower right photographing unit 5D. . Further, by matching the end Ec of the image data Dc with the left end Ea of the above synthesized upper composite image data and matching the end Ed of the image data Dd with the right end Eb, the image data Are generated, and a contour line indicating the entire cross-sectional shape P is generated.

  The image comparison determination unit 34 determines whether or not the cross-sectional image synthesized by the cross-sectional image synthesis unit 33 is within a predetermined shape. As shown in FIG. 7, the image comparison / determination means 34 stores a master image M as a comparison target of the combined cross-sectional images, and whether or not there is a cross-sectional image within the allowable range S of the master images M and M. By comparing and determining, the quality of the outer shape of the tread T is determined. As shown in FIG. 7, the master images M and M stored by the image comparison determination unit 34 are configured with a predetermined width so as to have an allowable range S in the pass / fail determination, and the combined cross-sectional shape P is within the allowable range S. If the cross-sectional shape P deviates from the permissible range S, it is determined as no (defect).

Hereinafter, the operation of the inspection processing means 3 of the shape measuring apparatus 1 according to the present invention will be described with reference to the flowchart of FIG.
First, each image data Da, Db, Dc, Dd photographed synchronously by the photographing means 5A to 5D is output to the inspection processing means 3.

The output image data Da, Db, Dc, and Dd are preprocessed by the image preprocessing unit 31 of the inspection processing unit 3, respectively.
In step 101, the image preprocessing means 31 scans the frame F of each image data Da, Db, Dc, Dd in the vertical direction, detects the maximum luminance value from each pixel row arranged in the vertical direction, and uses this maximum luminance value. A minimum luminance value is detected from a predetermined number of pixels in the vertical direction as the center.
Next, in step 102, the average value of the maximum luminance value and the average value of the minimum luminance value detected in each pixel column are calculated.
Next, in step 103, it is determined whether or not the difference between the average value of the maximum luminance values and the average value of the minimum luminance values, that is, the contrast value is greater than or equal to a predetermined value. If the contrast value is equal to or greater than the predetermined value, the process proceeds to step 104. If the contrast value is lower than the predetermined value, the process proceeds to step 105.

First, the case where the process proceeds to step 105 will be described.
In step 105, the image data that was captured immediately before the image data Da, Db, Dc, Dd being processed is recalled and superimposed on the image data being processed. As a result, the luminance value of each pixel at the same position of the previous image data is added to the luminance value of each pixel constituting the image data being processed, and the image data being processed is dark. The brightness value can be increased and the contrast value can be increased. Next, it returns to step 101 and repeats to step 103. Then, when the contrast value is equal to or greater than the predetermined value, the routine proceeds to step 104.

In step 104, each frame F of each image data obtained with a predetermined contrast value is scanned for each pixel column in the vertical direction, and the barycentric position G of the luminance value of each pixel column is calculated and stored.
Next, in step 106, the adjacent center-of-gravity position G set for each pixel column is linearly connected and set as the surface position in the cross-sectional shape P, and the process ends.

Next, step 107 is executed by the center position detecting means 32.
In step 107, a pair of protrusions 8 and 8 formed on the upper tread surface Ta are detected from the image data Da and the image data Db.
Next, in step 108, a small window W having a predetermined size is set between the detected protrusions 8 and 8.
Next, in step 109, the barycentric position G of the luminance values of the pixels constituting the small window W is calculated, and the barycentric position G is set as the tread center positions MA and MB of the respective image data Da and Db.

Next, in step 110, the tread center position MA specified by the image data Da and the tread center position MB specified by the image data Db are superimposed and combined with the upper composite image data.
Next, in step 111, the positions of the left and right ends Ea, Eb on the upper tread surface Ta are detected from the upper composite image data, and the arithmetic center position, which is a half of the length between the ends Ea, Eb, is determined. calculate.
Next, in step 112, it is determined whether or not the tread center position MA (MB) of the upper composite image data matches the arithmetic center position, and the tread center position MA (MB) matches the arithmetic center position. If yes, the process proceeds to step 113. If they do not match, the process proceeds to step 114, and a center position detection error is notified.

Next, step 113 is executed by the cross-sectional image synthesis means 33.
In step 113, the positions of both ends Ec and Ed of the tread T are detected from the image data Dc photographed by the lower left photographing means 5c and the image data Dd photographed by the lower right photographing means 5d, respectively, and the upper composite image data is detected. By matching the left end portion Ea of the image data Dc with the end portion Ec of the lower left image data Dc and the right end portion Eb of the upper composite image data with the end portion Ed of the lower right image data Dd, one cross section is obtained. Composite as a contour line of shape P.

Next, step 114 is executed by the image comparison determination means 34.
In step 114, it is determined whether or not the cross-sectional image combined by the cross-sectional image combining unit 33 is within the allowable range S of the master image M. When the combined cross-sectional image is within the allowable range S, it is output as “good”, and when the cross-sectional image protrudes from the allowable range S, it is output as “no” (defective).
By repeating the processing from step 101 to step 114 each time an image is taken, online processing of the cross-sectional shape P is executed.

  In the processing by the image preprocessing unit, the average value of the maximum luminance value and the average value of the minimum luminance value in the frame F have been described in units of the frame F. However, as another processing method, the frame F is equally By dividing the image into a plurality of areas and calculating the contrast value for each area, the contrast value may be set to a predetermined value or more by superimposing a minimum amount of image data.

In addition, although it has been described that the object to be measured is irradiated with the left and right slit lights, if the object to be measured is wider, the left and right slit lights can be used for the left and right of the object to be measured. The irradiating means may be configured so that the center side is photographed with the slit light at the center.
Further, the object to be measured is not limited to the measurement of the tire tread, and may be one that measures the shape of another member.

1 shape measuring device, 2 shape obtaining means, 3 inspection processing means, 4A to 4D projector,
5A to 5D photographing means, 8 protrusions, 31 image preprocessing means, 32 center position detecting means,
33 cross-sectional image synthesis means, 34 image comparison determination means,
Ca, Cb, Cc, Cd contour line, Da, Db, Dc, Dd image data,
G center of gravity, M master image, o center marker line, P cross-sectional shape,
T tread, Ta tread surface.

Claims (3)

The surface of the object to be measured is irradiated with slit light, and the irradiated object is scanned from the direction different from the optical axis of the slit light to obtain image data, and the object to be measured is scanned in the length direction. A method for measuring a shape of a belt-like rubber member for measuring a cross-sectional shape of an object to be measured,
A luminance value detection step of detecting a maximum luminance value and a minimum luminance value for each of a predetermined range of the image data;
A luminance centroid position setting step for setting, for each region, a luminance centroid position related to a luminance value in the region detected by the luminance value detection step;
A cross-sectional shape acquisition step of acquiring a cross-sectional shape by connecting the luminance gravity center positions adjacent to each other set by the luminance center-of-gravity position setting step ,
The luminance value detection step calculates a contrast value between the maximum luminance value and the minimum luminance value of each detected area, and calculates time for image data currently being processed when the contrast value is equal to or less than a predetermined threshold value. shape measuring method of the belt-shaped rubber member said contrast value by adding the image data obtained one time before, characterized that you treated as equal to or greater than a predetermined threshold value manner. The shape measuring method for a belt-shaped rubber member according to claim 1, wherein the object to be measured is a tire tread. The surface of the object to be measured is irradiated with slit light, and the irradiated object is scanned from the direction different from the optical axis of the slit light to acquire image data, and the object to be measured is scanned in the length direction to be measured. A shape measuring device for a belt-like rubber member for measuring a cross-sectional shape of a measurement object,
A luminance value detecting means for detecting a maximum luminance value and a minimum luminance value for each region of a predetermined range constituting the image data;
A luminance barycentric position setting unit that sets a luminance barycentric position for the luminance value in the area detected by the luminance value detecting unit for each area;
A cross-sectional shape obtaining unit that obtains a cross-sectional shape by connecting the luminance centroid positions adjacent to each other set by the luminance centroid position setting unit ;
The luminance value detecting means calculates a contrast value between the maximum luminance value and the minimum luminance value of each detected area, and calculates time for image data currently being processed when the contrast value is equal to or less than a predetermined threshold value. shape measuring apparatus of the belt-shaped rubber member said contrast value by adding the image data obtained one time before, characterized that you treated as equal to or greater than a predetermined threshold value manner.

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