JP2011247639A - Tire inspection device and tire inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire inspection device and a tire inspection method which are easily applicable to inspection of tires having different sizes of diameter.SOLUTION: A tire inspection device 1 is provided with: a first imaging part 10 for imaging an inspection face Ta of a tire T; a second imaging part 20 for imaging the inspection face Ta; and an image data correction part 103. The first imaging part 10 is arranged such that the inspection face Ta is imaged when an optical axis Ax10 of the first imaging part 10 is matched with a normal N1 in the directional view of the rotary axis of the tire; and the second imaging part 20 is arranged such that the inspection face Ta is imaged when an optical axis Ax20 of the second imaging part 20 is parallel with the normal N1. The image data correction part 103 is configured to correct the image obtained by the second imaging part 20 so that the image obtained by the second imaging part 20 can be matched with the image obtained by the first imaging part 10.

Description

  The present invention relates to a tire inspection apparatus and a tire inspection method that acquire an image of a tire and inspect the appearance and shape of the tire using the acquired image.

  2. Description of the Related Art Conventionally, a method has been proposed in which a tire image is acquired by a camera, and a tire shape and appearance quality are determined by comparing the acquired image with a reference image that is stored in advance as a reference (Patent Literature). 1).

  The tire inspection apparatus described in Patent Document 1 detects the shape of a tire by a so-called light cutting method. In other words, while irradiating the inspection surface of the tire with laser slit light at a predetermined angle, the unevenness of the inspection surface is detected by imaging the irradiation area of the laser slit light with an area camera in which image sensors are arranged in a matrix. is doing.

  Since it is difficult to determine the color using only the image acquired in this way using an area camera, the tire inspection apparatus acquires an image for determining the color using a line camera. By using different images for color determination and shape determination, the accuracy of pass / fail determination is improved.

  In this tire inspection apparatus, a tire to be inspected is installed on a rotary table in a state where the rotation center of the tire coincides with the rotary axis of the rotary table, and when the rotary table is rotated, an area camera and a line An image for the entire circumference of the inspection surface of the tire is acquired by scanning the camera.

  The optical axis of the area camera is fixed in a state of being directed to the inspection surface so as to coincide with a plane including a cross section in the tread width direction and the tire radial direction. The optical axis of the line camera is also fixed in a state of being directed to the inspection surface so as to coincide with a plane including a cross section in the tread width direction and the tire radial direction. The image captured by the area camera captured in this manner can be easily matched with the image captured by the line camera.

JP, 2001-249012, A, etc.

  However, the conventional tire inspection apparatus described above has room for improvement as follows. That is, in the tire inspection apparatus described in Patent Document 1, when the diameter size of a tire to be inspected changes, a plurality of numerical values such as a focal length and an imaging region are adjusted again for each of the area camera and the line camera. The adjustment work was complicated. In addition, even if an error is allowed for each numerical value, the error accumulates as the number of items to be adjusted increases, leading to a decrease in the accuracy of the pass / fail judgment.

  Accordingly, an object of the present invention is to provide a tire inspection apparatus and a tire inspection method that can be easily applied to inspection of tires having different diameter sizes.

  In order to solve the above-described problem, a first feature of the present invention is that a first imaging unit (first imaging unit 10) that images an inspection surface of a tire to be inspected, and the inspection of the tire (tire T). A second imaging unit (second imaging unit 20) that images a surface (inspection surface Ta), the first imaging unit, the second imaging unit, and the inspection surface of the tire relative to the circumferential direction of the tire. It is a tire inspection device (tire inspection device 1) that inspects the state of the tire based on an image of the entire circumference of the inspection surface of the tire acquired by rotating the first imaging unit, When viewed in the direction of the rotation axis of the tire (viewed in the direction of arrow A), the optical axis (Ax10) of the first imaging unit coincides with a predetermined normal line (normal line N1) and is arranged so as to image the inspection surface. And the second imaging unit is arranged in the direction of the rotation axis of the tire. In view, the optical axis (Ax20) of the second imaging unit is arranged to image the inspection surface in parallel to the predetermined normal line (normal line N1), and is acquired by the second imaging unit. The gist of the invention is to include an image correction unit (image data correction unit 103) that corrects the image acquired by the second imaging unit so that the image matches the image acquired by the first imaging unit.

  According to the first feature, the optical axis of the first imaging unit coincides with a predetermined normal line when viewed from the direction of the rotation axis of the tire, and is arranged so as to image the inspection surface. It arrange | positions so that an axis | shaft may image a test | inspection surface in parallel with the optical axis of a 1st imaging part. In addition, the image correction unit corrects the image acquired by the second imaging unit so that the image acquired by the second imaging unit matches the image acquired by the first imaging unit. For this reason, what is necessary is just to adjust the positional relationship of a 1st imaging part and an inspection surface in the tire inspection apparatus which concerns on this invention. The image acquired by the second imaging unit is corrected by the image correction unit, and the image acquired by the second imaging unit and the image acquired by the first imaging unit can be matched. Thereby, it is easily applicable to the inspection of tires having different diameter sizes.

  A second feature of the present invention relates to the first feature, wherein the first image pickup unit is an area camera in which image pickup devices are arranged in a matrix, and the second image pickup unit has an image pickup device in a linear shape. The main point is that the line cameras are arranged.

  According to the second feature, since the image for determining the shape and the image for determining the color can be acquired by separate cameras, the accuracy can be improved.

  A third feature of the present invention relates to the first feature, supports both the first imaging unit and the second imaging unit, an imaging distance between the first imaging unit and the inspection surface, and the The gist is to include a support mechanism (support mechanism 30, frame 31, guide part 32) that changes the imaging distance between the second imaging unit and the inspection surface.

  According to the third feature, the first imaging unit and the second imaging unit are both supported by the support mechanism that changes the imaging distance to the inspection surface. The imaging region imaged by one imaging unit and the imaging region imaged by the second imaging unit can be changed. Therefore, it can be easily applied to inspection of tires having different diameter sizes.

  A fourth feature of the present invention relates to the third feature, wherein the support mechanism is capable of setting a plurality of the imaging distances, and the second imaging is added to an image acquired by the first imaging unit. A conversion table (lookup table) for associating a corrected image acquired after being acquired by the unit with respect to each of the plurality of imaging distances, and the image correction unit is configured to perform the first imaging based on the conversion table. The gist is to make the image acquired by the unit coincide with the corrected image.

  According to the fourth feature, the image acquired by the first imaging unit and the corrected image corrected after being acquired by the second imaging unit are based on a conversion table prepared in advance for each tire diameter size. Since it can be expanded to three-dimensional coordinates, the arithmetic processing can be simplified.

  A fifth feature of the present invention is that a first imaging unit that images an inspection surface of a tire to be inspected, a second imaging unit that images the inspection surface of the tire, the first imaging unit, and the second Tire inspection for inspecting the state of the tire based on an image for the entire circumference of the inspection surface of the tire acquired by relatively rotating the imaging unit and the inspection surface of the tire in the circumferential direction of the tire A method of imaging the inspection surface in a state in which the optical axis of the first imaging unit coincides with a predetermined normal in the tire rotation axis direction view, and in the tire rotation axis view, Imaging the inspection surface in a state where the optical axis of the second imaging unit is parallel to the predetermined normal line, an image acquired by the second imaging unit, and an image acquired by the first imaging unit The second imaging unit so as to match Thus the subject matter that a step of correcting the acquired image.

  According to the present invention, it is possible to provide a tire inspection apparatus and a tire inspection method that can be easily applied to inspection of tires having different sizes in the radial direction.

FIG. 1 is a schematic diagram illustrating an external configuration of the tire inspection apparatus according to the present embodiment. FIG. 2 is a plan view of the tire inspection apparatus as seen from the direction of arrow A shown in FIG. FIG. 3 is a block diagram illustrating an internal configuration of the tire inspection apparatus according to the present embodiment. FIG. 4 is a flowchart for explaining the tire inspection method according to the present embodiment. FIG. 5 is a flowchart illustrating image correction executed by the image correction unit in the tire inspection method according to the present embodiment. FIG. 6A is a diagram for explaining a part of the image for the entire circumference acquired by the first imaging unit 10 (area camera), and the entire circumference acquired by the second imaging unit 20 (line camera). It is a figure explaining a part of minute image. FIG. 7 is a schematic diagram illustrating a process of associating pixels of an image acquired by the second imaging unit 20 (line camera) with pixels of an image acquired by the first imaging unit 10 (area camera).

  Embodiments of the present invention will be described with reference to the drawings. Specifically, (1) the external configuration of the tire inspection device, (2) the internal configuration of the tire inspection device, (3) the tire inspection method, (4) the image correction method, (5) the action / effect, (6) Other embodiments will be described.

  In the following description of the drawings, the same parts are denoted by the same reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

(1) External Configuration of Tire Inspection Device FIG. 1 is a schematic diagram illustrating an external configuration of a tire inspection device. FIG. 2 is a plan view of the tire inspection apparatus as seen from the direction of arrow A shown in FIG. The tire inspection apparatus 1 acquires an image of the tire T that is an inspection target, and inspects the state of the tire T using the acquired image. The tire inspection apparatus 1 includes a first imaging unit 10 and a second imaging unit 20 that image the inspection surface Ta of the tire T. The tire T to be inspected is installed on the turntable B in a state where the center axis of the tire T and the rotation center of the turntable B coincide with each other. A support mechanism 30 to which the first imaging unit 10 and the second imaging unit 20 are attached is disposed at the center of the tire T, and the inspection surface Ta of the tire T is the first imaging unit 10 and the second imaging unit. 20 relative to the rotation. Although not shown in FIG. 1, the tire inspection device 1 includes a control system that determines whether the tire T is good or bad based on images acquired by the first imaging unit 10 and the second imaging unit 20. Details of the control system will be described later.

  In the embodiment, the first imaging unit 10 is an area camera. The area camera is a CCD camera in which image pickup elements are arranged in a matrix, and includes a wavelength separation filter. The area camera can selectively capture the laser slit light having a wavelength of 660 nm emitted from the area projector 11 and take an image. The image captured by the area camera is suitable for determining the unevenness of the tire surface including scratches and deformations. The tire inspection apparatus 1 detects unevenness of the inspection surface Ta to be inspected by the first imaging unit 10 by a so-called light cutting method.

  In the embodiment, the second imaging unit 20 is a color line camera. The line camera is a CCD camera or a CMOS sensor in which imaging elements are arranged in a line shape, and can capture and capture light emitted from a light source (line projector 21) such as an LED. The second imaging unit 20 captures 1000 to 4000 frames per second. The image captured by the line camera is suitable for judging the color of the tire surface including color and dirt.

  The first imaging unit 10 is disposed to face the inspection surface Ta of the tire T to be inspected, and the optical axis Ax10 (see FIG. 2) of the objective lens of the first imaging unit 10 is in the tread width direction on the inspection surface Ta. And it arrange | positions so that it may correspond to the virtual plane S containing the cross section of a tire radial direction. In FIG. 1, the line portion L <b> 1 on the inspection surface Ta on the sidewall of the tire T to be inspected is the imaging region of the first imaging unit 10.

  The second imaging unit 20 is arranged at a position translated from the first imaging unit 10 by a predetermined distance L0 in a direction perpendicular to the plane S including the cross section in the tread width direction and the tire radial direction on the inspection surface Ta. The In FIG. 1, the line portion L <b> 2 on the inspection surface Ta on the sidewall of the tire T to be inspected corresponds to the imaging region of the second imaging unit 20. The line portion L3 is an imaging region of the line camera in the conventional tire inspection apparatus and tire inspection method, and coincides with the normal line of the tire T.

  In the direction of the arrow A shown in FIG. 1 of the tire T (viewed in the direction of the rotation axis), the first imaging unit 10 images the inspection surface Ta while the optical axis Ax10 of the first imaging unit 10 coincides with the normal line N1. Has been placed. Further, the second imaging unit 20 is arranged so that the optical axis Ax20 of the second imaging unit 20 images the inspection surface Ta in parallel with the normal line N1 when the tire T is viewed in the rotation axis direction.

  The first imaging unit 10 and the second imaging unit 20 are fixed to a common frame 31 in order to maintain the relative position and angle with respect to the inspection-symmetric tire T. The first imaging unit 10 is attached to a frame 31 (described later) so as to capture at least a part of the inspection surface Ta from the virtual plane S.

  The second imaging unit 20 is attached to the frame 31 so as to capture a position at a predetermined interval L from the position captured by the first imaging unit 10 on the inspection surface Ta. That is, the first imaging unit 10 and the second imaging unit 20 are fixed to the frame 31 with a predetermined interval (interval L0 in FIG. 1). In the embodiment, L = L0. The optical axis of the objective lens of the first imaging unit 10 and the optical axis of the objective lens of the CCD camera arranged at the center of the line of the second imaging unit 20 are at a predetermined angle (for example, 45 degrees) with respect to the inspection surface Ta. Is set.

  The support mechanism 30 includes a frame 31 and a guide portion 32, and the frame 31 is movably attached to the guide portion 32. In addition to the first imaging unit 10 and the second imaging unit 20, an area projector 11 for an area camera and a line projector 21 for a line camera are attached to the frame 31 in a predetermined positional relationship.

  The area projector 11 is a laser projector that projects laser slit light having a wavelength of 660 nm, and projects the laser light in a slit shape. Laser slit light (referred to as first slit light) emitted from the area projector 11 is irradiated in a line along the tire radial direction of the inspection surface Ta. The first imaging unit 10 (area camera) images the line portion L1 from a predetermined angle (for example, 45 degrees). Thereby, the unevenness | corrugation of a tire surface can be imaged.

  The line projector 21 is an LED projector. A plurality of LEDs are arranged in the line projector 12. The white light irradiated from the LED of the line projector 12 is irradiated around the line portion L2 parallel to and spaced from the first slit light irradiated to the line portion L1 of the inspection surface Ta.

  As the tire T is rotated by the turntable B, the line portions L1 and L2 continuously move on the inspection surface Ta. That is, the first imaging unit 10 and the second imaging unit 20 can acquire images for the entire circumference of the inspection surface Ta of the tire T.

(2) Internal Configuration of Tire Inspection Device Next, a control system of the tire inspection device 1 will be described. Whether the tire T is good or bad based on the appearance image and the shape image of the tire T is processed by the computer 100. FIG. 3 is a block diagram illustrating the internal configuration of the tire inspection apparatus 1.

  The computer 100 includes a first image input unit 101, a second image input unit 102, an image data correction unit 103, a determination unit 104, and a storage unit 105.

  The first image input unit 101 inputs image data of an image captured by the first imaging unit 10. The second image input unit 102 inputs image data of an image captured by the second imaging unit 20.

  The image data correction unit 103 corrects the image acquired by the second imaging unit 20 so that the image acquired by the second imaging unit 20 matches the image acquired by the first imaging unit 10. For example, it is acquired by the second imaging unit 20 based on information including the distance between the first imaging unit 10 and the inspection surface Ta and the angle between the inspection surface Ta and the optical axis of the objective lens of the first imaging unit 10. Correct the image. The image data correction unit 103 converts the image acquired by the second imaging unit 20 and the image acquired by the first imaging unit 10 from the coordinate system in the pixel to the actual physical coordinate system based on a lookup table described later. Then, in the actual physical coordinate system, conversion is performed to match the image acquired by the second imaging unit 20 with the image correction acquired by the first imaging unit 10. The converted image is again assigned to pixel coordinates using a lookup table.

  The image correction method using the look-up table executed by the image data correction unit 103 can follow the method disclosed in International Publication No. WO2006 / 054775.

  The determination unit 104 compares the image acquired by the first imaging unit 10 and the image corrected after being acquired by the second imaging unit 20 with a reference image that is a predetermined reference, thereby comparing the tire. Judge the quality.

  The storage unit 105 stores a lookup table. In addition, a reference image serving as a reference for determining the quality of the tire T is stored. In the lookup table, pixel coordinates and real coordinates of arbitrary points of an image captured by the first imaging unit 10 (area camera) and an image captured by the second imaging unit 20 (line camera) are associated with each other. It is a table.

  The storage unit 105 includes at least information such as the distance between the inspection surface Ta of the tire T to be inspected and the first imaging unit 10 and the angle formed between the inspection surface Ta and the optical axis of the objective lens of the first imaging unit 10. Is stored.

  In addition to this, the tire inspection apparatus 1 includes an area projector 11 for an area camera, a light projecting control unit 106 that controls light projection in a line projector 21 for a line camera, a motor control unit 108 that controls the rotary table B, and an image. The image processing unit 107 that executes processing for displaying the image on the monitor 120 and outputs it to the monitor is included. The plurality of LEDs provided in the line projector 12 are individually controllable in light quantity, and are projected so that the light quantity of the image captured by the second imaging unit 20 (line camera) becomes an appropriate constant value. The light control unit 106 performs feedback control. The motor control unit 108 controls a motor (not shown) that rotates the rotary table B. The motor is driven and controlled by the motor control unit 108 and rotates a rotary table (not shown in FIG. 3) on which the tire to be imaged is placed. On the monitor 120, the inspection result of the tire T to be inspected is displayed.

(3) Tire Inspection Method Next, a tire inspection method by the tire inspection apparatus 1 having the above-described configuration will be described. FIG. 4 is a flowchart for explaining the tire inspection method according to the present embodiment.

  In step S <b> 1, the tire T is set in the tire inspection apparatus 1. In step S <b> 2, the computer 100 rotates the turntable B to rotate the tire T with respect to the first imaging unit 10 and the second imaging unit 20.

  In step S <b> 3, the computer 100 irradiates the line portion L <b> 1 of the inspection surface Ta of the tire T with measurement light from the area projector 11 and the line projector 21, and the line portion L <b> 1 is lined by the first imaging unit 10. The part L2 is imaged by the second imaging unit 20, respectively.

  In the tire inspection method shown in FIG. 4, in step S <b> 4, the computer 100 determines whether or not imaging has been performed over the entire circumference of the inspection surface Ta of the tire T, and while the imaging has not been completed over the entire circumference. Steps S3 and S4 are repeated. That is, by rotating the tire T, the computer 100 moves the line portions L1 and L2 to be imaged with respect to the inspection surface Ta and continues the imaging. When imaging is completed over the entire circumference, the process proceeds to step S5. That is, the computer 100 stops the rotary table.

  In step S <b> 6, the computer 100 performs the second imaging based on information such as the distance between the first imaging unit 10 and the inspection surface Ta and the angle between the inspection surface Ta and the optical axis of the objective lens of the first imaging unit 10. The image acquired by the unit 20 is corrected. Thereafter, the computer 100 synthesizes the image acquired by the first imaging unit 10 and the image corrected after being acquired by the second imaging unit 20.

  In step S <b> 7, the computer 100 determines the quality of the tire by comparing the synthesized image with a predetermined reference image. In the tire inspection method shown in FIG. 4, the pass / fail determination is determined to be good if the degree of shading of the image is within the allowable range, and is determined to be defective if it exceeds the allowable range. Moreover, the quality on the shape of a tire is determined based on an image. The computer 100 may set a mark on the defective portion of the image. The monitor 120 displays the determination result for the tire T that is the inspection target.

(4) Image Correction Method Next, the image correction executed in step S6 of the tire inspection method will be described in detail. FIG. 5 is a diagram for explaining image correction. FIG. 6A is a schematic diagram for explaining a part of an image for the entire circumference imaged by the first imaging unit 10, and FIG. 6B is an entire circumference imaged by the second imaging unit 20. It is a schematic diagram explaining a part of image for minutes.

  Photographed while rotating the tire at a constant speed with the optical axis of the area camera and the optical axis of the line camera arranged so as to coincide with the virtual plane S including the cross section in the tread width direction and the tire radial direction on the inspection surface Ta, respectively. By shifting the images (for example, images taken in the line portions L1 and L3 in FIG. 5) in the rotation direction, the pixels capturing the same subject can be made to correspond to each other.

  On the other hand, in the tire inspection apparatus 1 of the present embodiment, the first imaging unit 10 is attached to the frame 31 so as to image the (line portion L1) of the inspection surface Ta from the virtual plane S, and the second imaging unit 20 Is attached to the frame 31 so as to image a line portion L2 that is separated from the imaging position (line portion L1) by the first imaging unit 10 on the inspection surface Ta. That is, on the inspection surface Ta, the line portion L1 and the line portion L2 that are imaging regions are set to be parallel. For this reason, the image acquired by the second imaging unit 20 includes rotational distortion corresponding to the angle θ radians formed by the tire radial direction and the line portion L2 (see FIG. 6B). Therefore, in the present embodiment, the same image as that obtained when the line portion L2 imaged by the second imaging unit 20 is acquired in a state of being arranged so as to coincide with the virtual plane S including the cross section in the tread width direction and the tire radial direction. The image acquired by the second imaging unit 20 is corrected so that

  An image correction method will be described below. This correction is a process of associating the pixels of the image 202 acquired by the second imaging unit 20 (line camera) with the pixels of the image 201 acquired by the first imaging unit 10 (area camera). FIG. 7 is a schematic diagram illustrating the correction process. In this correction, as shown in FIG. 7, the pixel (X01, Y01) is associated with the pixel (X11, Y11). That is, color information such as the color tone and gradation of the pixel (X01, Y01) capturing the subject is assigned to the pixel (X11, Y11). Similarly, the pixel (X02, Y02) is associated with the pixel (X12, Y12).

(4-1) Radial Direction Correction of Image Obtained by Second Imaging Unit 20 Radial direction correction will be described with reference to FIG. The radially inner end of the line portion L1 is a point a, and the radially inner end of the line portion L2 is a point A ′. The radius of rotation from the rotation center of the tire T to the point a is defined as radius R. Further, an intersection of the imaginary line l1 passing through the point a and orthogonal to the line part L1 and the line part L2 is defined as a point A. The distance between point a and point A is represented by L. It is assumed that a plane coordinate system is set in FIG. 5, the position of the point A is represented by real coordinates (I, J), and the position of the point A ′ is represented by real coordinates (I ′, J ′).

The image of the entire circumference acquired by the second imaging unit 20 (line camera) is longer than the image acquired by the first imaging unit 10 (area camera) by the error dr in the W direction. When the angle θ formed by the straight line connecting the rotation center O of the tire T and the point a and the straight line connecting the center O and the point A ′, the angle θ is calculated by the following equation (1).

Therefore, the error dr is calculated by the following equation.

Subsequently, based on the error dr in the W direction, the radial error dr of the image for the entire circumference acquired by the second imaging unit 20 (line camera) is corrected. Subsequently, coordinates (physical coordinates) in an actual three-dimensional space are calculated. The physical coordinates of the points A and A ′ are calculated by the following equations (3) and (4).

Next, the physical coordinates (X, Y) of the point A are obtained from the pixel coordinates (I, J) of the point A using a lookup table. Further, the physical coordinates (X ′, Y ′) of the point A ′ are calculated by the equations (5) and (6).

  Next, the pixel coordinates (I ′, J ′) of the point A ′ are obtained from the physical coordinates (X ′, Y ′) of the point A ′ using a lookup table. As described above, based on the calculated linear distance dr, it is possible to perform correction for converting the physical coordinates (X ′, Y ′) of the point A ′ to the physical coordinates (X, Y) of the point A.

(4-1) Correction of circumferential direction of image acquired by second imaging unit 20 Correction of the circumferential direction will be described with reference to FIG. In the circumferential direction, correction is performed so that the deviation in the rotation direction (D direction) increases from the rotation center O toward the radially outer side of the tire T. An arbitrary point on the line portion L2 is corrected corresponding to the line portion L3. That is, the correction amount m at an arbitrary point p on the line portion L2 is obtained. The correction amount m is calculated by the following equation (7).

From equation (1), the value of θ is substituted into the above equation.

Next, in the following equation (9), the amount by which the pixel at the point p is shifted to the corresponding point q in the line portion L3 (that is, the number up to the destination pixel after the conversion of the pixel information at the point p). A certain shift amount K is calculated. The shift amount K is expressed by the following equation (9), where S is the number of images to be captured by the second imaging unit 20 in order to obtain image data for the entire circumference.

  Therefore, by moving the pixel by the shift amount K calculated as described above in the circumferential direction, the pixel of the image 202 acquired by the second imaging unit 20 (line camera) is converted into the first imaging unit 10. It can be associated with the pixels of the image 201 acquired by the (area camera).

(5) Action / Effect According to the tire inspection apparatus 1 of the embodiment, the optical axis Ax10 of the first imaging unit 10 coincides with the predetermined normal line N1 when the tire T is viewed in the direction of the rotation axis (viewed in the direction of arrow A). The optical axis Ax20 of the second imaging unit 20 is arranged so as to image the inspection surface Ta in parallel with the optical axis Ax10 of the first imaging unit 10. Further, the image data correction unit 103 corrects the image acquired by the second imaging unit 20 so that the image acquired by the second imaging unit 20 matches the image acquired by the first imaging unit 10.

  For this reason, in the tire inspection apparatus 1, only the positional relationship between the first imaging unit 10 and the inspection surface Ta needs to be adjusted. The image acquired by the second imaging unit 20 is corrected by the image data correction unit 103 to match the image acquired by the second imaging unit 20 with the image acquired by the first imaging unit 10. Can do. Thereby, it is easily applicable to the inspection of tires having different diameter sizes.

  In the tire inspection apparatus 1, the first imaging unit 10 is an area camera in which imaging elements are arranged in a matrix, and the second imaging unit 20 is a line camera in which imaging elements are arranged in a straight line. That is, since the image for determining the shape and the image for determining the color can be acquired by separate cameras, the accuracy can be improved.

  The tire inspection apparatus 1 supports both the first imaging unit 10 and the second imaging unit 20, the imaging distance between the first imaging unit 10 and the inspection surface Ta, and the second imaging unit 20 and the inspection surface Ta. A support mechanism 30 for changing the imaging distance, a frame 31, and a guide portion 32 are provided. In the tire inspection apparatus 1, the first imaging unit 10 and the second imaging unit 20 are both operably supported by the support mechanism 30, and therefore the first imaging unit 10 can be simply changed by the support mechanism 30 by changing the imaging distance. The width of the imaging region (line portion L1) imaged by the second imaging unit 20 and the width of the imaging region (line portion L2) imaged by the second imaging unit 20 can be changed. Therefore, it can be easily applied to inspection of tires having different diameter sizes.

  In the tire inspection apparatus 1, the support mechanism 30 can set a plurality of imaging distances, and an image acquired by the first imaging unit 10 is corrected to a corrected image acquired after being acquired by the second imaging unit 20. It has a lookup table for correspondence. The image data correction unit 103 converts the image acquired by the first imaging unit 10 based on the lookup table and the correction image into three-dimensional coordinates, and performs correction to match both images in the three-dimensional coordinate system. After that, the pixel coordinate system is converted again. As described above, the image acquired by the first imaging unit 10 and the corrected image corrected after being acquired by the second imaging unit 20 can be developed into three-dimensional coordinates based on the lookup table. Can be simplified.

  The tire inspection apparatus 1 can cope with a change in the tire size of the tire to be inspected by setting only the imaging distance of the support mechanism 30 by converting the image by the image data correction unit 103. With conventional tire inspection equipment, if the diameter of the tire to be inspected changes, multiple values such as focal length and imaging area must be adjusted for each of the area camera and line camera. However, the tire inspection apparatus 1 can be easily applied to inspection of tires having different diameter sizes.

(6) Other Embodiments As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the above-described embodiment, after the correspondence between the shape image data and the appearance image data is corrected, the image data acquired by the appearance image data acquisition unit 104 is combined with the image data acquired by the shape image data acquisition unit 102. . However, the image data acquired by the shape image data acquisition unit 102 may be combined with the image data acquired by the appearance image data acquisition unit 104 after correcting the association between the shape image data and the appearance image data.

  The case where the tire T images the inspection surface Ta while the tire T rotates with the rotation center O as the rotation axis has been described. However, it may be anything that rotates relatively. For example, the tire T may be fixed, and the tire inspection apparatus 1 may circulate while imaging the inspection surface Ta.

  A color line camera can be used as the line camera. By applying the color line camera, the appearance data of the subject can be obtained as a color image. Therefore, the quality of the tire T can be easily determined.

  A three-plate line camera can also be used as the line camera. The three-plate line camera is a camera in which a separate CCD camera takes an image for each of R, G, and B, which are the three primary colors. Appearance data of each primary color can be obtained, and the quality of the tire T can be determined more accurately.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

  DESCRIPTION OF SYMBOLS 1 ... Tire inspection apparatus, 10 ... 1st imaging part, 11 ... Area projector, 12 ... Line projector, 20 ... 2nd imaging part, 21 ... Line projector, 30 ... Support mechanism, 31 ... Frame, 32 ... Guide part, 100 DESCRIPTION OF SYMBOLS ... Computer 101 ... 1st image input part 102 ... Shape image data acquisition part 102 ... 2nd image input part 103 ... Image correction part 104 ... Determination part 104 ... Appearance image data acquisition part 105 ... Memory | storage part 106 ... Projection control unit, 107 ... Image processing unit, 108 ... Motor control unit, 120 ... Monitor, 201 ... Image, 202 ... Image, Ax10, 20 ... Optical axis, B ... Rotary table

Claims (5)

A first imaging unit that images an inspection surface of a tire to be inspected;
A second imaging unit that images the inspection surface of the tire;
Based on an image for the entire circumference of the inspection surface of the tire acquired by rotating the first imaging unit and the second imaging unit and the inspection surface of the tire relative to each other in the circumferential direction of the tire. A tire inspection apparatus for inspecting the state of the tire,
The first imaging unit includes:
When viewed in the direction of the rotation axis of the tire, the optical axis of the first imaging unit is arranged so as to coincide with a predetermined normal and image the inspection surface,
The second imaging unit
In the tire rotation axis direction view, the optical axis of the second imaging unit is arranged to image the inspection surface parallel to the predetermined normal line,
A tire inspection apparatus comprising: an image correction unit that corrects the image acquired by the second imaging unit so that the image acquired by the second imaging unit and the image acquired by the first imaging unit match. The first imaging unit is an area camera in which imaging elements are arranged in a matrix,
The tire inspection apparatus according to claim 1, wherein the second imaging unit is a line camera in which imaging elements are linearly arranged.   Supporting both the first imaging unit and the second imaging unit, and changing the imaging distance between the first imaging unit and the inspection surface and the imaging distance between the second imaging unit and the inspection surface The tire inspection apparatus according to claim 1, further comprising a mechanism. The support mechanism is capable of setting a plurality of the imaging distances,
A conversion table that associates the image acquired by the first imaging unit with the corrected image corrected after being acquired by the second imaging unit;
The image correction unit
The tire inspection apparatus according to claim 3, wherein an image acquired by the first imaging unit based on the conversion table is matched with the corrected image. A first imaging unit that images an inspection surface of a tire to be inspected;
A second imaging unit that images the inspection surface of the tire;
Based on an image for the entire circumference of the inspection surface of the tire acquired by rotating the first imaging unit and the second imaging unit and the inspection surface of the tire relative to each other in the circumferential direction of the tire. A tire inspection method for inspecting a state of the tire,
Imaging the inspection surface in a state in which the optical axis of the first imaging unit coincides with a predetermined normal in the tire rotation axis direction view;
In the rotational axis view of the tire, imaging the inspection surface in a state where the optical axis of the second imaging unit is parallel to the predetermined normal;
Correcting the image acquired by the second imaging unit so that the image acquired by the second imaging unit matches the image acquired by the first imaging unit.

Images