JP5088007B2 - Tire inspection method and apparatus - Google Patents

Description

  The present invention relates to a tire inspection method and apparatus for non-destructively inspecting the state of a belt member of an automotive pneumatic tire, for example.

  In general, as an inspection method for this type of tire, an X-ray is emitted from the inner peripheral surface side of the tire toward the tire, and the image pickup device is disposed on the outer peripheral surface side of the tire while rotating the tire in the circumferential direction. In addition to taking a transmitted X-ray image that has passed through the tire by the display, the captured image is displayed on a display device, and the inspector visually determines the state of the belt cord in the image displayed by the display device It has been known.

In addition, as another tire inspection method, a transmission X-ray image is captured by the imaging device as described above, and the reference data stored in advance is compared with the captured image, and the reference data is captured. An apparatus that determines the state of a belt cord based on a difference from an image is known (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 9-15172

  By the way, in the former inspection method, since the inspector visually determines the state of the belt cord and the like, it is difficult to improve the determination accuracy and it is difficult to shorten the time required for the inspection. there were.

  In the latter inspection method, reference data stored in advance and a captured image are compared, and a belt code state or the like is determined based on a difference between the reference data and the captured image. Since the reference data is created by imaging a plurality of tires and averaging the images, for example, a detailed determination is made as to whether or not the belt end meanders where the end in the width direction of the belt member meanders. There was a problem that it was not possible.

  Further, since it is necessary to create and store the reference data for each tire type, there is a problem that the time required for the inspection is increased by the amount of creation of the reference data.

  The present invention has been made in view of the above-described problems, and an object thereof is a tire capable of accurately determining the presence or absence of belt end meandering and reducing the time required for inspection. An inspection method and apparatus therefor are provided.

In order to achieve the above object, the present invention irradiates the tire with electromagnetic waves such as X-rays and γ rays from the inner peripheral surface side of the tire, and transmits the tire by an imaging device disposed on the outer peripheral surface side of the tire. In the tire inspection method for capturing whether or not a belt end meandering in which the width direction end portion of the belt member meanders in the tire that has taken the transmitted electromagnetic wave image, the image is picked up by the imaging device. A belt code region determining step for determining a belt code region where the belt code in the image is imaged, and an end width line for determining an end portion of the belt code region in the image width direction in the image width direction. When the size is equal to or higher than reference dimension, seen including a a determination step of determining a tire having captured the belt end portion meandering occurs the transmitted radiation image, the belt coding region Make An enhancement step for enhancing the contrast of the image captured by the imaging device, and an orthogonal component enhancement step for enhancing a component in a direction substantially orthogonal to the direction in which the carcass code extends in the image whose contrast is enhanced by the enhancement step. A region determining step of determining a belt code region by determining a region in which the components emphasized by the orthogonal component emphasizing step in the image picked up by the imaging device are gathered .

The present invention also provides an irradiation device that irradiates the tire with electromagnetic waves such as X-rays and γ rays from the inner peripheral surface side of the tire, and a transmitted electromagnetic wave image that is disposed on the outer peripheral surface side of the tire and transmits through the tire. An image picked up by an image pickup device in a tire inspection device for inspecting whether or not a belt end meandering in which a width direction end portion of a belt member meanders has occurred in a tire that has taken a transmission electromagnetic wave image. Dimension in the image width direction of the belt code area determining means for determining the belt code area in which the inner belt code is imaged and the end width defining line for determining the end portion in the image width direction in the belt code area If There becomes equal to or higher than the reference size, the tire of the captured transmitted radiation image and a and determination means belt ends meandering occurs, the belt cord area determining means, the imaging apparatus An image is picked up by an enhancement device that enhances the contrast of the image captured in this way, an orthogonal component enhancement device that enhances a component in a direction substantially orthogonal to the direction in which the carcass code extends in the image whose contrast is enhanced by the enhancement device, and an imaging device There is provided area determining means for determining a belt code area by determining an area in which the components emphasized by the orthogonal component enhancing means in the image are gathered .

As a result, the belt code region in which the belt code in the image captured by the imaging device is captured is determined, and the end determination line for determining the end in the image width direction in the belt code region is present. When the dimension in the image width direction is equal to or larger than the reference dimension, it is determined that the belt end meandering has occurred in the tire that captured the transmitted electromagnetic wave image. For example, the image width direction in the range where the end definite line exists If the belt end meanders so that the size of the belt is 30 mm and the reference dimension is set to 25 mm, the dimension in the image width direction in the range where the end definite line exists is equal to or larger than the reference dimension. Thus, it is determined that the belt end meandering has occurred. In this case, the contrast of the image captured by the imaging device is enhanced, the components in the direction substantially orthogonal to the extending direction of each carcass code in the image with the enhanced contrast are enhanced, and the enhanced components are collected. Since the belt code area is determined by determining the area, the belt code area can always be determined accurately even when the width dimension of the belt member changes depending on the tire type.

According to the present invention, for example, the belt end meandering occurs so that the dimension in the image width direction in the range where the end definite line exists is 30 mm, and the reference dimension is set to 25 mm. Since it is determined that the belt end meandering has occurred because the dimension in the image width direction in the range where the end line is present exceeds the reference dimension, the reference dimension is appropriately set according to the tire type and the like By doing so, the presence or absence of the belt end meandering can be accurately determined. In addition, it is possible to make a determination automatically without using visual inspection, and it is not necessary to create reference data for each tire type, which is extremely advantageous in reducing the time required for inspection. In this case, since the belt code area can always be determined accurately, it is extremely advantageous to accurately determine the presence or absence of the belt end meandering. In particular, in the tire T having the metal carcass cord CC, the belt cord region can be accurately determined, and in the tire T having the metal carcass cord CC, it is possible to accurately determine whether or not the belt end meanders. Is very advantageous.

  1 to 10 show an embodiment of the present invention. FIG. 1 is a schematic diagram of an irradiation apparatus and an imaging apparatus, FIG. 2 is a block diagram of a tire inspection apparatus, and FIG. 3 is a control unit of the first control apparatus. FIG. 4 to FIG. 10 are schematic diagrams of images processed by the control unit of the first control device.

  The tire inspection apparatus of the present embodiment is disposed on the inner peripheral surface side of the tire T, and is disposed on the outer peripheral surface side of the tire T and the irradiation device 10 that irradiates X-rays toward the tire T, and transmits through the tire T. An imaging apparatus 20 that captures a transmitted X-ray image as a transmitted electromagnetic wave image, and an inspection apparatus main body 30 connected to the imaging apparatus 20 are provided. The tire T is rotatably supported by a support device (not shown). The tire T is a radial tire arranged such that a plurality of metal carcass cords CC extend in the radial direction. A plurality of belt members are provided on the outer peripheral surface side of the tire T, and each belt member has a plurality of metal belt cords BC. Each belt member is provided so as to extend in the circumferential direction of the tire T, but the end in the width direction of the belt member may meander, and such a phenomenon is referred to as belt end meandering.

  The irradiation device 10 is formed of a known X-ray tube that radiates X-rays radially, and is arranged on the inner peripheral surface side of the tire T supported by the support device. It is also possible to configure so that γ rays are irradiated instead of X rays.

  The imaging device 20 includes an upper camera 21 disposed on the upper side of the tire T supported by the support device, and a pair of side cameras 22 disposed on both sides in the width direction of the tire T supported by the support device. Each of the cameras 21 and 22 is a known line sensor camera, and each of the cameras 21 and 22 captures a transmission X-ray image transmitted through the tire T in a linear shape. That is, a transmission X-ray image for one round of the tire T is taken by taking images at predetermined intervals by the cameras 21 and 22 while rotating the tire T at a predetermined speed in the circumferential direction by the support device.

  As shown in FIG. 2, the inspection apparatus main body 30 includes first to third control apparatuses 31, 32, and 33. Each of the control devices 31, 32, 33 includes control units 31a, 32a, 33a, display units 31b, 32b, 33b such as a liquid crystal display screen, and storage units 31c, 32c, 33c such as a hard disk. The control units 31a, 32a, and 33a are well-known microcomputers having an arithmetic device, a storage device, an input device, and the like. Furthermore, an image captured by the upper camera 21 in the imaging device 20 is transmitted to the control unit 31a of the first control device 31, and an image captured by one side camera 22 among the side cameras 22 is subjected to the second control. An image transmitted to the control unit 32 a of the device 32 and captured by the other side camera 22 among the side cameras 22 is transmitted to the control unit 33 a of the third control device 33.

  In the tire inspection apparatus configured as described above, the camera 21 and 22 perform imaging at predetermined intervals while rotating the tire T in the circumferential direction at a predetermined speed by a support device (not shown) as described above. A transmission X-ray image of one round of the tire T is captured, and images captured by the cameras 21 and 22 are transmitted as digital images to the control units 31a, 32a, and 33a of the control devices 31, 32, and 33, respectively. In addition, it is also possible to create an image for one round of the tire T by connecting the linear imaging data captured by the cameras 21 and 22 in the control devices 31, 32, and 33.

  Subsequently, the control unit 31a of the first control device 31 performs image processing of an image for one round of the tire T, and determines whether or not the belt end meanders based on the image processed image. Each of the control devices 32 and 33 also performs image processing of an image for one round of the tire T by the control units 32a and 33a, and inspects the tire T based on the image processed image. The operation of the control unit 31a of the first control device 31 at this time will be described with reference to the flowchart shown in FIG. Here, the image of one round of the tire T transmitted to the control unit 31a of the first control device 31 is an image of the tire T taken from the outside in the radial direction, and each belt member is placed on the center side in the width direction of the image. A plurality of metal belt cords BC are imaged, and a plurality of metal carcass cords CC constituting the carcass member are imaged on both sides of the belt cord BC in the width direction (see FIG. 4). FIG. 4 shows a part of an image for one round of the tire T. FIG. The carcass cords CC are arranged so as to extend in the image width direction, and are arranged at intervals in the vertical direction of the image. The belt cords BC are arranged at a predetermined angle with the extending direction of the carcass cords CC, and are arranged at intervals in the vertical direction of the image. Here, images other than each belt code BC and each carcass code CC are not captured in the image transmitted from the upper camera 21. For example, when a background is captured in the image transmitted from the upper camera 21, each of the images transmitted from the upper camera 21 is subjected to differential processing from the transmitted image. It is preferable to remove things other than the belt cord BC and each carcass cord CC.

  First, when an image for one round of the tire T is transmitted from the upper camera 21 to the control unit 31a of the first control device 31 (SA1), the contrast of the image is enhanced (SA2). This contrast enhancement is performed using a known process such as a linear conversion process, a binarization process, and a luminance slicing process. Thereby, each belt code BC and each carcass code CC in the image are clarified (see FIG. 5). It is also possible to perform step SA3 and subsequent steps without performing step SA2.

  Subsequently, the component in the vertical direction of the image (the direction substantially perpendicular to the direction in which each carcass code CC extends) is emphasized in the image with enhanced contrast (SA3). The enhancement of the component in the vertical direction of the image is performed by a known method using, for example, a shift process and a differential process in the vertical direction of the image. Thereby, each belt code BC in the image is emphasized, and each carcass code CC is thinned or removed (see FIG. 6).

  Subsequently, the contrast of the image in which the vertical component of the image is enhanced is enhanced (SA4). This contrast enhancement is performed using a known process such as a linear conversion process, a binarization process, and a luminance slicing process. Thereby, each belt code BC in the image becomes clear (see FIG. 7).

  Subsequently, a belt code area in which each belt code BC in the image captured by the imaging device is captured is determined (SA5). This region determination is performed, for example, by appropriately performing shift processing and addition processing in the vertical direction of the image, after filling the region where the components (each belt code BC) emphasized in step SA3 are gathered (see FIG. 8). For example, by performing edge emphasis processing using a Prewitt filter or Sobel filter, an outline OL for determining a region having the largest area among the regions where the components emphasized in step SA3 are gathered is created (FIG. 9). reference). Here, the contour line OL is a contour line of the belt code region. Note that by performing expansion processing for expanding each line on the image instead of the shift processing and addition processing, it is also possible to fill the region where the components emphasized in step SA3 are gathered. It is also possible to determine the belt code region based on an average density per unit area (for example, a range of several pixels × several pixels).

  Subsequently, with respect to a pair of width direction end line OL1 for determining the end part in the image width direction in the belt code region, the dimension L1 in the image width direction in the range where each end line determination line OL1 exists is set to each end part. Detection is performed for each confirmed line OL1 (SA6, see FIG. 10). Here, since the image on which image processing is performed by the control unit 31a is an image for one round of the tire T, the dimension L1 is detected for the image for one round of the tire T.

  Subsequently, when the dimension L1 detected for each end determination line OL1 is equal to or larger than a reference dimension L0 (for example, 25 mm), belt end meandering occurs in the tire T that has captured the transmitted X-ray image. (SA7).

  Subsequently, when it is determined in step SA7 that the belt end meandering has occurred (SA8), the image before the contrast enhancement in step SA2 is displayed on the display unit 31b, and the belt end meandering has occurred. A display process for displaying the edge determination line OL1 on the side determined to be conspicuous is performed, and a storage process for storing the measurement date and time, the type of the measured tire T, the determination result, and the like in the storage unit 31c is performed ( SA9). If it is not determined in step SA7 that the belt end meandering has occurred (SA8), a storage process for storing the measurement date and time, the type of tire T measured, the determination result, etc. is performed in the storage unit 31c (SA10).

  As described above, according to the present embodiment, the belt code region in which each belt code BC in the image captured by the imaging device 20 is captured is determined, and the end of the belt code region in the image width direction is determined. When the dimension L1 in the image width direction in the range where the pair of width direction end line OL1 exists is equal to or larger than the reference dimension L0 (for example, 25 mm), the belt end meanders on the tire T that has captured the transmitted X-ray image. Therefore, for example, the belt end is set so that the dimension L1 in the image width direction in the range where at least one end determination line OL1 exists among the end determination lines OL1 is 30 mm or more. When the part meandering has occurred, it is determined that the belt end meandering has occurred because the dimension L1 in the image width direction in the range where the end defining line OL1 exists is equal to or larger than the reference dimension L0. It is. That is, by appropriately setting the reference dimension L0 according to the type of the tire T, the presence / absence of the belt end meandering can be accurately determined. In addition, it is possible to make a determination automatically without visual observation, and it is not necessary to create reference data for each tire type, which is extremely advantageous in reducing the time required for inspection.

  Further, the image picked up by the image pickup device 20 is subjected to the image processing as described above by the control unit 31a of the control device 31, and the presence or absence of meandering of the belt end is automatically inspected. Compared with the case where the inspector visually confirms the image and inspects whether or not the belt end meanders, the inspection accuracy and speed can be improved.

  In addition, the contrast of the image captured by the imaging device 20 is enhanced (step SA2), and the component in the direction substantially orthogonal to the direction in which each carcass code CC extends in the image with enhanced contrast is enhanced (step SA3). The belt code region is determined by determining the region where the components emphasized in step SA3 are gathered. For this reason, even when the width dimension of the belt member changes according to the type of the tire T, the belt cord area can always be accurately determined, and it is extremely difficult to accurately determine the presence or absence of the belt end meandering. It is advantageous. In particular, in the tire T having the metal carcass cord CC, the belt cord region can be accurately determined, and in the tire T having the metal carcass cord CC, it is possible to accurately determine whether or not the belt end meanders. Is very advantageous.

  In the present embodiment, the control unit 31a of the control device 31 performs image processing of an image for one round of the tire T, and determines the presence or absence of belt end meandering based on the image processed image. On the other hand, it is also possible to perform image processing of an image obtained by capturing a part of the tire T by the control unit 31a of the control device 31, and to determine the presence or absence of the belt end meandering based on the image subjected to the image processing. is there.

  In the present embodiment, the steps SA1 to SA10 are performed by the control unit 31a of the first control device 31. However, any step of the steps SA1 to SA10 is performed by the inspector, for example, the control unit 31a. It can also be performed by operation.

  In the present embodiment, the tire T having the metal carcass cord CC is inspected for the presence of the meandering of the belt end, but in the case of the tire T having the resinous carcass cord CC. Even if it exists, it is possible to test | inspect the presence or absence of a belt edge part meander similarly to the above-mentioned.

  In the present embodiment, the image captured by the imaging device 20 is shown in which both ends in the width direction of the belt member are present. However, each width direction end of the belt member is included in the image captured by the imaging device 20. Even if only one of the end portions in the width direction is present, the presence or absence of meandering of the belt end portion can be inspected in the same manner as described above.

Schematic of an irradiation apparatus and an imaging apparatus showing an embodiment of the present invention Block diagram of tire inspection equipment The flowchart which shows operation | movement of the control part of a 1st control apparatus. Schematic of an image processed by the control unit of the first control device Schematic of an image processed by the control unit of the first control device Schematic of an image processed by the control unit of the first control device Schematic of an image processed by the control unit of the first control device Schematic of an image processed by the control unit of the first control device Schematic of an image processed by the control unit of the first control device Schematic of an image processed by the control unit of the first control device

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Irradiation device, 20 ... Imaging device, 21 ... Upper camera, 22 ... Side camera, 30 ... Inspection apparatus main body, 31 ... 1st control apparatus, 31a ... Control part, 31b ... Display part, 31c ... Storage part, 32 ... second control device, 32a ... control unit, 32b ... display unit, 32c ... storage unit, 33 ... third control device, 33a ... control unit, 33b ... display unit, 33c ... storage unit, CC ... carcass code, BC ... Belt cord, T ... tire.

Claims (2)

An electromagnetic wave such as X-rays or γ rays is irradiated toward the tire from the inner peripheral surface side of the tire, and a transmitted electromagnetic wave image transmitted through the tire is imaged by an imaging device disposed on the outer peripheral surface side of the tire. In the tire inspection method for inspecting whether or not the belt end meandering in which the widthwise end of the belt member meanders is generated in the tire imaged,
A belt code area determining step for determining a belt code area in which a belt code in an image captured by an imaging device is captured;
If the dimension in the image width direction in the range where the edge defining line that defines the edge in the image width direction in the belt code area exceeds the reference dimension, the belt end meandering occurs in the tire capturing the transmitted electromagnetic wave image. look including a determination step of determining that,
In the belt code area determination step, an emphasis step for emphasizing the contrast of the image captured by the imaging device, and a component in a direction substantially orthogonal to the direction in which the carcass code extends in the image whose contrast is enhanced by the emphasis step are emphasized. Including an orthogonal component emphasizing step and an area determining step for determining a belt code area by determining an area where the components emphasized by the orthogonal component emphasizing step in the image captured by the imaging device are gathered. A tire inspection method that is characterized. An irradiation device that irradiates the tire with electromagnetic waves such as X-rays and γ rays from the inner peripheral surface side of the tire, and an imaging device that is disposed on the outer peripheral surface side of the tire and picks up a transmitted electromagnetic wave image transmitted through the tire In the tire inspection apparatus for inspecting whether or not the belt end meandering in which the width direction end of the belt member meanders in the tire that has captured the transmitted electromagnetic wave image,
Belt code area determining means for determining a belt code area in which a belt code in an image captured by an imaging device is captured;
If the dimension in the image width direction in the range where the edge defining line that defines the edge in the image width direction in the belt code area exceeds the reference dimension, the belt end meandering occurs in the tire capturing the transmitted electromagnetic wave image. Determination means for determining that the
The belt code region determining means emphasizes the enhancement means for enhancing the contrast of the image captured by the imaging device, and the component in the direction substantially orthogonal to the direction in which the carcass code extends in the image whose contrast is enhanced by the enhancement means. There is provided orthogonal component emphasizing means and area determining means for determining the belt code area by determining an area where the components emphasized by the orthogonal component emphasizing means in the image captured by the imaging device are gathered. A tire inspection device.

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