System and method for evaluating ozone degradation of vulcanized rubber

Abstract

To provide a vulcanized rubber ozone deterioration evaluation system and a method which can accurately and efficiently evaluate ozone deterioration.SOLUTION: A vulcanized rubber ozone deterioration evaluation system holds a large number of test samples S by a holding part 2A in an extended sate, relatively moves at least one of the holding part 2A and a camera device 3 by controlling the movement of a movement mechanism 4 by a control part 5, sequentially positions each test sample S held by the holding part 2A or the camera device 3 at a prescribed imaging position for each preset elapsed time, acquires image data M in the front view of a surface Sf of each test sample S at the prescribed imaging position by the camera device 3 in such a state that a back plate 8 is arranged on a back side while emitting light by illumination means 7, and calculates an evaluation index Dx for evaluating an ozone deterioration degree of each test sample S by a calculation device 6 on the basis of the result of image processing on the image data M by the calculation device 6.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a system and method for evaluating ozone degradation of vulcanized rubber, and more particularly to a system and method for evaluating ozone degradation of vulcanized rubber that can evaluate ozone degradation more accurately and efficiently. [Background technology]

[0002] The static ozone degradation test, specified in JIS K 6259-1:2015 "Vulcanized and thermoplastic rubber - Determination of ozone resistance," is widely known as a method for evaluating ozone degradation of vulcanized rubber. This test method requires a considerable amount of work, as the tester must record the degradation status at regular intervals. Furthermore, differences in the tester's judgment can lead to variations in the evaluation results.

[0003] Various methods have been proposed for quantitatively evaluating ozone degradation of vulcanized rubber, using image data obtained by photographing vulcanized rubber test samples (see, for example, Patent Documents 1 and 2). In these proposed evaluation methods, the image data is analyzed to calculate the area of ​​ozone cracks and the like, which is used as an evaluation index. By using such an evaluation index, it is possible to eliminate variations in evaluation results due to human judgment.

[0004] However, even for test samples with the same specifications, there are some individual differences in the degree of ozone degradation. Therefore, to evaluate the ozone degradation of test samples with each specification with higher accuracy, it is desirable to test a large number of test samples with each specification. Furthermore, to compare the degree of ozone degradation between test samples with different specifications, it is desirable to test each test sample at the same time. However, with various evaluation methods proposed in the past, testing a large number of test samples requires sequentially replacing and attaching the test samples to a holder, which is disadvantageous for efficient evaluation. Therefore, there is room for improvement in evaluating the ozone degradation of vulcanized rubber more accurately and efficiently. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-45142 [Patent Document 2] Japanese Patent Publication No. 2020-118462 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a system and method for evaluating ozone degradation of vulcanized rubber that can evaluate ozone degradation more accurately and efficiently. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a system for evaluating ozone degradation of vulcanized rubber, which comprises a holding mechanism for holding a test sample of vulcanized rubber in an elongated state, a camera device for acquiring image data of the surface of the test sample, and a calculation device for performing image processing of the image data, and an evaluation index for evaluating the degree of ozone degradation of the test sample is calculated by the calculation device based on the results of the image processing. In this system, the holding mechanism has holding sections for holding a large number of the test samples, and comprises a movement mechanism for relatively moving at least one of the holding mechanism and the camera device, and a control section for controlling this movement mechanism. By relatively moving at least one of the holding mechanism and the camera device by the movement mechanism, each of the test samples or the camera device held in the holding mechanism is sequentially positioned at a predetermined photographing position at every preset elapsed time, and the image data of a front view of the surface of each of the test samples at the predetermined photographing position is acquired by the camera device. a back plate placed behind each of the test samples at the predetermined photographing position, and the difference in saturation in the CIELAB color space between the surface color of each of the test samples in the image data and the surface color of the back plate is 20 or more. It is characterized by: Another system for evaluating ozone degradation of vulcanized rubber according to the present invention comprises a holding mechanism for holding a vulcanized rubber test sample in an elongated state, a camera device for acquiring image data of the surface of the test sample, and a computing device for image processing of the image data, and the computing device calculates an evaluation index for evaluating the degree of ozone degradation of the test sample based on the results of the image processing. The system is characterized in that the holding mechanism has a holding section for holding a large number of test samples, and the system has a movement mechanism for relatively moving at least one of the holding mechanism and the camera device, and a control section for controlling the movement mechanism, and the movement mechanism causes the relative movement of at least one of the holding mechanism and the camera device so that each of the test samples or each of the camera devices held in the holding mechanism is sequentially positioned at a predetermined photographing position at a predetermined elapsed time, and the image data of a front view of the surface of each of the test samples at the predetermined photographing position is acquired by the camera device, and the system has a back panel placed behind each of the test samples at the predetermined photographing position, and the difference in lightness in CIELAB color space between the color of the surface of each of the test samples in the image data and the color of the surface of the back panel is 20 or more. Another system for evaluating ozone degradation of vulcanized rubber according to the present invention comprises a holding mechanism for holding a test sample of vulcanized rubber in an elongated state, a camera device for acquiring image data of the surface of the test sample, and a calculation device for performing image processing of the image data, and the calculation device calculates an evaluation index for evaluating the degree of ozone degradation of the test sample based on the results of the image processing. The system is characterized in that the holding mechanism has holding sections for holding a large number of the test samples, and the system also has a movement mechanism for relatively moving at least one of the holding mechanism and the camera device, and a control unit for controlling the movement mechanism. The movement mechanism moves at least one of the holding mechanism and the camera device relative to each other, so that each of the test samples or each of the camera devices held in the holding mechanism is sequentially positioned at a predetermined photographing position every preset elapsed time, and the image data of a front view of the surface of each of the test samples at the predetermined photographing position is acquired by the camera device, and the system has a back panel placed on the back side of each of the test samples at the predetermined photographing position, and the reflectance of the surface of the back panel is 50% or less.

[0008] The method for evaluating ozone degradation of vulcanized rubber of the present invention involves using a camera device to obtain image data of the surface of a test sample of vulcanized rubber held in an elongated state by a holding mechanism, and using a computing device to calculate an evaluation index for evaluating the degree of ozone degradation of the test sample based on the results of image processing of the obtained image data by the computing device, wherein the holding mechanism holds a large number of test samples, and controls relative movement of at least one of the holding mechanism and the camera device to sequentially position each of the test samples held by the holding mechanism or the camera device at a predetermined photographing position every predetermined elapsed time, and obtains the image data of a front view of each of the test samples at the predetermined photographing position by the camera device. A back plate is placed behind each of the test samples at the predetermined photographing position, and the difference in chroma and / or lightness in the CIELAB color space between the surface color of each of the test samples in the image data and the surface color of the back plate is set to 20 or more. It is characterized by: Another method for evaluating ozone degradation of vulcanized rubber of the present invention involves using a camera device to obtain image data of the surface of a vulcanized rubber test sample held in an elongated state by a holding mechanism, and using a computing device to calculate an evaluation index for evaluating the degree of ozone degradation of the test sample based on the results of image processing of the obtained image data by the computing device, characterized in that the holding mechanism holds a large number of test samples, and controls the relative movement of at least one of the holding mechanism and the camera device to sequentially position each of the test samples held in the holding mechanism or the camera device at a predetermined shooting position every predetermined elapsed time, obtains the image data of a front view of each of the test samples at the predetermined shooting position by the camera device, and places a back panel on the back side of each of the test samples at the predetermined shooting position, and sets the reflectance of the surface of the back panel to 50% or less. [Effects of the Invention]

[0009] According to the present invention, the evaluation index is calculated based on the results of image processing of the image data of the surface of each of the test samples by the arithmetic device, so that the degree of ozone deterioration of each of the test samples can be objectively evaluated using the evaluation index. Furthermore, the holding mechanism holds a large number of the test samples, and the camera device is controlled to sequentially acquire the image data of the front view of each of the test samples at the predetermined photographing position every predetermined elapsed time. Therefore, it is possible to accurately and efficiently evaluate the ozone deterioration of each of the test samples. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an explanatory diagram illustrating the system for evaluating ozone degradation of vulcanized rubber according to the present invention, showing the inside of a test tank in vertical cross section. FIG. [Figure 2] 2 is an explanatory diagram illustrating the inside and outside of the test tank of FIG. 1 in plan view. FIG. [Figure 3] FIG. 2 is an enlarged view of a portion of FIG. [Figure 4]FIG. 4 is an explanatory diagram illustrating the test sample of FIG. 3 as viewed from the front. [Figure 5] FIG. 10 is an explanatory diagram illustrating image data of a front view of a test sample acquired by a camera device. [Figure 6] 6 is a graph illustrating an example of the distribution state of saturation in the analysis range of the image data of FIG. 5. [Figure 7] 6 is a graph illustrating an example of the distribution of brightness in the analysis range of the image data of FIG. 5. FIG. [Figure 8] 6 is an explanatory diagram illustrating image data of a test sample extracted by image processing the analysis range of the image data of FIG. 5. FIG. [Figure 9] 9 is an explanatory diagram illustrating image data in which the image data of FIG. 8 is subjected to image processing to separate an ozone crack region from other regions. FIG. [Figure 10] FIG. 10 is an explanatory diagram illustrating a state in which a circumscribing rectangle is fitted to an ozone crack region of image data. [Figure 11] 10 is an explanatory diagram illustrating, in plan view, the inside and outside of a test chamber of another embodiment of the evaluation system. FIG. [Figure 12] FIG. 10 is an explanatory diagram illustrating yet another embodiment of the evaluation system, showing the interior of a test tank in vertical cross section. [Figure 13] 13 is an explanatory diagram illustrating the inside and outside of the test tank of FIG. 12 in plan view. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the system and method for evaluating ozone degradation of vulcanized rubber according to the present invention will be described based on the embodiments shown in the drawings.

[0012] 1 to 4, an ozone degradation evaluation system 1 for vulcanized rubber (hereinafter referred to as evaluation system 1) is capable of sequentially and continuously acquiring front-view image data M of a large number of vulcanized rubber test samples S. To this end, evaluation system 1 includes a holding mechanism 2 that holds each of the large number of test samples S in an elongated state, a camera device 3 that acquires image data M of the surface Sf of each test sample S, a computing device 6 that performs image processing of each piece of image data M, a moving mechanism 4 that moves at least one of the holding mechanism 2 and the camera device 3 relatively, a control unit 5 that controls this moving mechanism 4, and a monitor 9.

[0013] This embodiment of the evaluation system 1 further includes a lighting means 7, a back panel 8, a test chamber 10, and an ozone injector 11. The lighting means 7, the back panel 8, the test chamber 10, and the ozone injector 11 may be included as an option.

[0014] The test sample S may be, for example, any of the various dumbbell-shaped samples specified by JIS. Alternatively, any desired test sample S may be used, such as a cut sample of an actual rubber product or an approximate sample that imitates a rubber product. The test samples S may have the same specifications or different specifications. Test samples S with different elongation states (magnitude of tensile strain) may also be mixed.

[0015] The holding mechanism 2 has multiple holding portions 2A. Each holding portion 2A holds one or more test samples S in an extended state. In this embodiment, 12 holding portions 2A are provided, and each holding portion 2A holds five test samples S, so that a total of 60 test samples S are held by the holding mechanism 2. The number of test samples S that can be held by the holding mechanism 2 is, for example, 10 or more, and more preferably 20 or more. The upper limit of the number of test samples S that can be held by the holding mechanism 2 is limited mainly by the installation space, but is, for example, around 200 or 300.

[0016] Each holding portion 2A has a pair of clamps 2b whose separation distance is adjustable. For example, the pair of clamps 2b can be connected by a ball screw or the like to adjust the separation distance. One clamp 2b holds one end of the test sample S, and the other clamp 2b holds the other end of the test sample S. The greater the separation distance between the clamps 2b, the greater the stretching of the test sample S. In Figure 4, each test sample S is stretched in the vertical direction.

[0017] The elongation state (magnitude of tensile strain) of the test sample S can be set to any desired degree, such as 10%, 20%, or 30%. For example, the tensile strain applied to the test sample S can be set in accordance with the test method of JIS K 6259-1:2015. The test sample S can also be elongated so that the magnitude of the tensile strain is the same as that applied to a vulcanized rubber with the same specifications as the test sample S when it is actually used as a rubber product.

[0018] The camera device 3 acquires front-view image data M of the surface Sf of each test sample S at a predetermined shooting position. The camera device 3 may acquire either digital still image data or digital video image data. The angle α1 between the shooting direction of the camera device 3 (extension direction of the shooting lens unit 3a) and the extension direction (extension direction) of the surface Sf is approximately 90° (85° or more and 90° or less). In other words, the shooting direction of the camera device 3 is approximately perpendicular to the surface Sf of the test sample S. The camera device 3 is not limited to one, and multiple camera devices 3 may be provided.

[0019] The moving mechanism 4 moves at least one of the holding mechanism 2 and the camera device 3 relative to one another, and sequentially positions each test sample S held by the holding mechanism 2 or the camera device 3 at a predetermined photographing position every preset elapsed time T. In this embodiment, the camera device 3 is fixed at the predetermined photographing position, and the holding mechanism 2 is moved by the moving mechanism 4.

[0020] In this embodiment, the movement mechanism 4 includes a swivel base 4b that rotates around a vertically extending rotation axis 4c, and a drive motor such as a servo motor 4a that rotates the swivel base 4b around the rotation axis 4c. Each holding unit 2A is provided upright on the swivel base 4b. Therefore, by rotating the swivel base 4b with the movement mechanism 4, the holding mechanism 2 moves, and each test sample S is sequentially positioned at a predetermined photographing position. The holding mechanism 2 can be fixed and the camera device 3 can be moved by the movement mechanism 4, or both the holding mechanism 2 and the camera device 3 can be moved.

[0021] The above-mentioned elapsed time T is set to, for example, 2, 4, 8, 24, 48, 72, 96 hours, etc. from the start of the test in accordance with the test method of JIS K 6259-1:2015. This elapsed time T can be set arbitrarily as needed, and can also be set to, for example, every 10 minutes, every hour, etc.

[0022] The control unit 5 controls the moving mechanism 4. In this embodiment, the control unit 5 controls the operation and stopping, rotation angle, etc. of the servo motor 4a that constitutes the moving mechanism 4, and moves each test sample S sequentially to a predetermined photographing position every preset elapsed time T. A computer is used as the control unit 5.

[0023] The arithmetic device 6 receives the image data M acquired by the camera device 3. Other known image processing programs and various data are also input to and stored in the arithmetic device 6. The arithmetic device 6 then processes the input image data M and calculates an evaluation index Dx for evaluating the degree of ozone degradation of each test sample S based on the image processing results. Various known computers can be used as the arithmetic device 6. The control unit 5 and the arithmetic device 6 may be provided separately, or the arithmetic device 6 and the control unit 5 may be shared, with the arithmetic device 6 functioning as the control unit 5.

[0024] The lighting means 7 irradiates light onto the surface Sf of each test sample S at a predetermined photographing position. Various known electric lamps such as incandescent lamps (light bulbs), fluorescent lamps, and LEDs can be used as the lighting means 7. A circular electric lamp surrounding the photographing lens unit 3a of the camera device 3 can also be used as the lighting means 7. The lighting means 7 is not limited to one unit, and multiple units can also be provided.

[0025] The angle α2 between the optical axis direction of the light emitted from the illumination means 7 and the extension direction of the surface Sf is 10° or more and 80° or less, and more preferably 50° or more and 70° or less. That is, it is preferable that the optical axis direction of the illumination means 7 is close to perpendicular to the surface Sf of the test sample S, but if it is too close to perpendicular, it becomes difficult to identify ozone cracks Cr in the image data M. As in this embodiment, the illumination means 7 is preferably attached to the inner wall surface of the test chamber 10 so that it can be swiveled (tilted) and the optical axis direction can be easily changed to the desired direction. The upper limit of angle α1 is 90°, and the upper limit of angle α2 is 80°.

[0026] The back plate 8 is placed at a predetermined shooting position on the back side of each test sample S. The area of ​​the back plate 8 is larger than the shooting range of each test sample S, and in the field of view from the side of each test sample S, the entire shooting range of the test sample S is located within the area of ​​the back plate 8.

[0027] In this embodiment, a cylindrical back plate 8 is disposed on the back side of each holding portion 2A. The outer peripheral surface of the cylinder forms the surface 8a of the back plate 8. This back plate 8 is engaged with each holding portion 2A, and as the swivel base 4b rotates, it rotates together with each holding portion 2A.

[0028] The back plate 8 only needs to be placed on the back side of each test sample S at a predetermined shooting position, so in this embodiment, the back plate 8 may be placed only at a position facing the camera device 3, and the test sample S positioned at the predetermined shooting position may be between the back plate 8 and the camera device 3. One back plate 8 may be provided for each test sample S, or one back plate 8 may be provided for each of a plurality of test samples S.

[0029] The surface 8a of the back panel 8 is preferably a monochrome color (easy to distinguish) different from the color of the surface Sf of the test sample S. Therefore, it is preferable that the difference in saturation between the color of the surface Sf of each test sample S in the image data M and the color of the surface 8a of the back panel 8 is 20 or more, or the difference in lightness is 20 or more, and it is more preferable that the difference in saturation is 20 or more and the difference in lightness is 20 or more. The numerical values ​​of the saturation and lightness are calculated based on the saturation (C*={(a*) 2 +(b*) 2} 1 / 2 ), and lightness (L*). When the surface Sf of the test sample S is black, the surface 8a of the back panel 8 is made green, red, blue, or the like. When the surface Sf of the test sample S is not black, the surface 8a of the back panel 8 is made black, or the like.

[0030] The reflectance of the surface 8a of the back panel 8 is preferably 50% or less. This reflectance is a value measured in accordance with the measurement of specular reflectance in JIS Z 8741. In other words, the surface 8a of the back panel 8 is preferably a color that is not easily reflective. The back panel 8 is formed, for example, from resin, paper, wood, or metal with a matte finish applied to the surface 8a.

[0031] The monitor 9 is connected to the arithmetic device 6 so as to be able to communicate with the arithmetic device 6. The monitor 9 displays the image data M obtained by the camera device 3, the results of calculations by the arithmetic device 6, and the like.

[0032] Test chamber 10 is a container whose interior can be sealed, and ozone Z is supplied from ozone injector 11 so that the ozone concentration in test chamber 10 can be set to a desired concentration. For example, ozone injector 11 is installed in a circulation path that supplies ozone Z, and the circulation path is equipped with an exhaust pipe and the like via an exhaust purification filter and an on-off valve 11a. Transparent resin or glass is used for the area of ​​the wall of test chamber 10 that faces the photographing lens unit 3a of camera device 3 (the area necessary for camera device 3 to photograph the surface Sf of test sample S).

[0033] A predetermined ozone concentration is maintained inside the test chamber 10. The maintained ozone concentration is set, for example, in accordance with the test method of JIS K 6259-1:2015, to 500±50 ppb (50±5 pphm), 250±50 ppb (25±5 pphm), 1000±100 ppb (100±10 pphm), or 2000±200 ppb (200±20 pphm). It is also possible to set an ozone concentration that approximates the conditions under which rubber products are actually used. If the test chamber 10 is not used, each test sample S is placed under atmospheric conditions.

[0034] The internal temperature and humidity of the test chamber 10 are set within an appropriate desired range. These conditions should conform to the test method of JIS K 6259-1:2015. Therefore, the internal temperature of the test chamber 10 should be 40±2°C, and the relative humidity at the internal temperature should be 65% or less. However, the internal temperature and humidity can also be set to approximate the conditions under which the rubber product will actually be used.

[0035] Next, an example of the procedure for the ozone degradation evaluation method of the present invention will be described.

[0036] As shown in FIGS. 1 to 3, each test sample S is placed in a test chamber 10 having a predetermined ozone concentration under preset placement conditions. The test chamber 10 is maintained at a predetermined ozone concentration, and the brightness and angle α2 of the light irradiated by the lighting means 7 are appropriately set. The internal temperature and humidity are set within appropriate desired ranges. Each test sample S can be new, or it can be a test sample S that has undergone a predetermined test (such as a test in which dynamic elongation strain is repeatedly applied).

[0037] Multiple test samples S with the same specifications can be placed in the same elongated state, or multiple test samples S with the same specifications can be placed in different elongated states. Alternatively, multiple test samples S with different specifications can be placed in the same elongated state, or multiple test samples S with different specifications can be placed in different elongated states.

[0038] 4, the moving mechanism 4 is operated to position each test sample S at a predetermined photographing position (a position facing the photographing lens unit 3a of the camera device 3) at every preset elapsed time T. Next, the surface Sf of each test sample S is photographed from a fixed point in front view by the camera device 3 at the predetermined photographing position to obtain image data M.

[0039] Ozone cracks Cr (hereinafter referred to as cracks Cr) occur on the surface Sf of the test sample S over time due to the cleavage of the chemical bonds of the rubber molecules in the test sample S by ozone Z. As these cracks Cr grow over time, their length and area gradually increase. The cracks Cr tend to grow and extend in a direction (horizontal direction in Figure 4) perpendicular to the direction in which the test sample S is stretched (vertical direction in Figure 4).

[0040] 4, in this embodiment, of five test samples S held in parallel in one holder 2A, one test sample S in the left-right middle is positioned at a predetermined photographing position. After acquiring image data M of the surface Sf of this one test sample S as viewed from the front, the swivel base 4b is rotated to position the next test sample S to the left at the predetermined photographing position, and image data M of the surface Sf of this test sample S as viewed from the front is acquired. Thereafter, each test sample S is similarly positioned at the predetermined photographing position, and the surface Sf is photographed from a fixed point as viewed from the front with the camera device 3, and image data M is acquired.

[0041] Alternatively, if it is possible to acquire image data M of a front view of the surfaces Sf of multiple (e.g., all five) test samples S held in one holder 2A at a predetermined shooting position, the image data may be acquired in that manner. If a method for acquiring image data M of multiple test samples S at once is used, it becomes unnecessary to rotate the swivel table 4b at small angles many times in order to acquire image data M of all test samples S. On the other hand, a method for positioning each test sample S at a predetermined shooting position and acquiring image data M is advantageous in suppressing variations in the image data M due to the shooting environment.

[0042] 5, image data M acquired by the camera device 3 is sequentially input to and stored in the arithmetic device 6. The image data M input to the arithmetic device 6 is displayed on the monitor 9.

[0043] In this embodiment, the acquired image data M of each test sample S is subjected to image processing by the calculation device 6. Based on the results of this image processing, the calculation device 6 calculates an evaluation index Dx for evaluating the degree of ozone degradation of each test sample S.

[0044] The image processing and the procedure for calculating the evaluation index Dx will be described in detail below.

[0045] In this embodiment, the back plate 8 is placed on the back side of each test sample S at a predetermined photographing position. Therefore, as illustrated in Fig. 5, the acquired image data M includes image data of the front view of the surface Sf of the test sample S as well as image data of the surface 8a of the back plate 8.

[0046] Therefore, image processing is performed on the analysis range R (the range within the rectangular frame) of the image data M shown in Fig. 5 to identify and separate the surface Sf of the test sample S and the surface 8a of the back panel 8. When this identification and separation is performed, accurate identification and separation is facilitated if the difference in saturation between the color of the surface Sf of the test sample S in the image data M and the color of the surface 8a of the back panel 8 is 20 or more, or if the difference in saturation is 20 or more and the difference in brightness is 20 or more. To improve this accuracy, it is more preferable that the surface 8a of the back panel 8 is a single color.

[0047] Figures 6 and 7 show examples of a saturation histogram and a brightness histogram, respectively, for the image data M in Figure 5. Figures 6 and 7 show data for a case where the color of surface Sf is black like ordinary vulcanized rubber, the color of surface 8a is green, and the reflectance of surface 8a is 30%.

[0048] In Figure 6, the saturation range of approximately 10 to 70 corresponds to the surface Sf of the test sample S, and the saturation range of approximately 130 to 200 corresponds to the surface 8a of the rear panel 8. In Figure 7, the lightness range of approximately 90 to 140 corresponds to the surface Sf of the test sample S, and the lightness range of approximately 120 to 230 corresponds to the surface 8a of the rear panel 8.

[0049] Therefore, a known image processing program that utilizes the difference in saturation and brightness between surface Sf and surface 8a is installed in the arithmetic device 6, and this program is executed to perform image processing, thereby identifying and separating surface Sf and surface 8a in the image data M. This image processing can obtain the image data M shown in FIG. 8. The image data M in FIG. 8 is processed by setting threshold values ​​for each of saturation and brightness, thereby identifying and separating surface Sf and surface 8a. Various other known image processing methods can also be used to identify and separate surface Sf and surface 8a.

[0050] 5 may be processed using only the difference in saturation or only the difference in brightness, but employing image processing that utilizes the difference in saturation and brightness is advantageous for accurately identifying and separating surface Sf from surface 8a. Furthermore, if the reflectance of surface 8a is too high, it becomes difficult to accurately identify and separate the two, so the reflectance is set to 50% or less, more preferably 30% or less.

[0051] Next, image processing is performed on the image data M of Fig. 8 to distinguish and separate the crack Cr region on the surface Sf of the test sample S from other regions (the base material of the surface Sf) and binarize the image data. Prior to this binarization image processing, noise removal processing is performed on the image data M as needed. For noise removal processing, various known noise processing methods such as a noise removal filter (e.g., a Gaussian filter) can be used.

[0052] The binarization image processing performed on the image data M in Fig. 8 can be performed using various known methods, and the method is not particularly limited. For example, a method of binarizing by setting a threshold value, a method of binarizing by using a region separation model generated by machine learning, etc. can be exemplified. do

[0053] This binarization image processing can obtain image data M, as shown in Fig. 9. In the image data M in Fig. 9, the crack Cr region is displayed in white, and the other region (the base material of the surface Sf) is displayed in black.

[0054] The edges of the cracks Cr tend to rise slightly above the surface Sf of the test sample S. Therefore, if the angle α2 formed between the surface Sf of the test sample S and the optical axis direction of the light irradiated from the illumination means 7 is less than 10°, the edges of the cracks Cr will cast clear shadows on the surface Sf, increasing the risk of misidentifying these shadows as cracks Cr. Therefore, in order to accurately distinguish and separate the crack Cr region from other regions (the base material of the surface Sf), the angle α2 should be set to 10° or more, more preferably 50° or more, and even more preferably 60° or more, but not more than 80°.

[0055] Next, an evaluation index Dx is calculated using the image data M of Fig. 9. As the evaluation index Dx, for example, at least one of the number, length L, contour length, and area of ​​cracks Cr that have occurred on the surface Sf of each test sample S is calculated by the calculation device 6. The length L of the crack Cr is calculated by fitting a circumscribing rectangle Sq (shown by a dashed line in Fig. 10) to the area of ​​the crack Cr, as shown in Fig. 10, and taking the length of the long side of the circumscribing rectangle Sq as an example. A known fitting program may be used to fit the circumscribing rectangle Sq to the area of ​​the crack Cr.

[0056] For a large number of test samples S with the same specifications, evaluation indices Dx such as the number of cracks Cr, length L, contour length, and area are obtained, and the mean, median, variance, etc. of these evaluation indices Dx are calculated per unit area for each test sample S with the same specifications. When evaluating the ozone degradation of each test sample S with each specification, the magnitude of the mean, median, variance, etc. of at least one type of evaluation indices Dx per unit area is used. By using multiple types of evaluation indices Dx, the degree of ozone degradation of the test sample S can be evaluated from multiple perspectives.

[0057] As described above, the evaluation index Dx is calculated based on the results of image processing of image data M of the surface Sf of each test sample S by the arithmetic unit 6. Therefore, by using the calculated evaluation index Dx, the degree of ozone deterioration of each test sample S can be objectively evaluated, and variations in the evaluation results due to human judgment can be eliminated.

[0058] A large number of test samples S are held in the holding mechanism 2, and front-view image data M of each test sample S is acquired sequentially at a predetermined shooting position at preset intervals, making it possible to more efficiently evaluate ozone degradation. Also, since evaluation tests can be performed simultaneously using a large number of test samples S with single or multiple specifications, variation in test conditions is reduced, making it even more advantageous for accurately evaluating ozone degradation of the test samples S.

[0059] If the wall surface of the test tank 10 is present between the camera device 3 and the test sample S, noise may be introduced into the image data M due to light reflection from this wall surface, etc. Therefore, at least the photographing lens portion 3a of the camera device 3 may be inserted from the outside to the inside of the test tank 10 through a through-hole formed in the test tank 10. The gap between the outer circumferential surface of the photographing lens portion 3a and the through-hole is sealed with a sealant.

[0060] The image data M and the evaluation index Dx can be sequentially input and stored via an internet line or the like in a computing device 6 installed in a management office or the like away from the test tank 10 and the camera device 3. Therefore, the change over time in ozone degradation of the surface of the test sample S can be grasped in the management office or the like.

[0061] The multiple test samples S are not limited to a configuration in which they are sequentially positioned at predetermined photographing positions by rotation of the swivel table 4b, and various other configurations can be adopted. For example, the evaluation system 1 may be equipped with a plurality of panel bodies to which one or more holders 2A are attached. Then, a moving mechanism 4 such as a fluid cylinder may be used to sequentially move the panel bodies, sequentially positioning each test sample S at a predetermined photographing location, and acquiring image data M.

[0062] In the above-described embodiment, a swivel table 4b having a circular shape in a plan view is used. However, various other configurations can be adopted to sequentially move each test sample S. As illustrated in FIG. 11, a movement mechanism 4 can also be adopted in which the movement path of each test sample S is oval in a plan view. In this embodiment, for example, a chain 4d or the like is guided by an oval-shaped guide rail, and the chain 4d is rotationally driven by a servo motor 4a. This moves each holding unit 2A connected to the chain 4d, and each test sample S moves along the oval-shaped movement path. In this embodiment, the back panel 8 provided on each holding unit 2A moves along with the respective holding unit 2A.

[0063] Then, each test sample S (holding unit 2A) is sequentially positioned at a predetermined photographing position (a position where the camera device 3 is disposed) at a predetermined elapsed time interval. At the predetermined photographing position, image data M of the surface Sf of each test sample S in a front view is acquired by the camera device 3. In this embodiment, it is preferable to set the predetermined photographing position on a portion of a linear movement path in a planar view. This makes it easier to suppress noise and the like from being introduced into the image data of the surface Sf of the test sample S acquired by the camera device 3.

[0064] 12 and 13 is configured so that the holding mechanism 2 is fixed and the camera device 3 is moved by the moving mechanism 4. Other specifications are substantially the same as those of the previous embodiment.

[0065] In this evaluation system 1, the camera device 3 is placed on a swivel base 4b. The test tank 10 is cylindrical (cylindrical), and the camera device 3 is located in the center of the test tank 10 in a plan view (the external space of the test tank 10). As the swivel base 4b rotates around a rotation axis 4c, the camera device 3 also rotates. The lighting means 7 is installed on the outer circumferential surface of the inner cylindrical surface of the test tank 10 (i.e., it is located in the internal space of the test tank 10). For example, it is preferable to attach a rail extending circumferentially around the outer circumferential surface of the inner cylindrical surface of the test tank 10, and move the lighting means 7 along this rail in synchronization with the rotation of the camera device 3.

[0066] The holding mechanism 2 and back plate 8 are arranged in the annular internal space of the test chamber 10. More specifically, in this embodiment, 24 holding units 2A are arranged in a ring shape around the rotation axis 4c in a plan view. Each holding unit 2A holds one test sample S, and a total of 20 test samples S are held by the holding mechanism 2. The cylindrical back plate 8 is arranged on the outer periphery of each holding unit 2A.

[0067] The camera device 3 is moved by the moving mechanism 4, and is sequentially positioned at predetermined photographing positions (positions where the respective test samples S are disposed) at predetermined elapsed time intervals. At the predetermined photographing positions, the camera device 3 acquires image data M of the front view of the surface Sf of each test sample S.

[0068] The procedure for evaluating the ozone deterioration of each test sample S is the same as in the previous embodiment. In this embodiment, each test sample S does not move, which has the advantage that unnecessary vibrations (stimuli) are not applied to the test sample S. [Explanation of symbols]

[0069] 1. Rating System 2 Retention mechanism 2A holding part 2b Clamp 3 Camera equipment 3a Shooting lens section 4 Moving mechanism 4a servo motor 4b Swivel base 4c pivot axis 4d chain body 5. Control section 6 Arithmetic unit 7 Lighting means 8 Back plate 8a surface 9 Monitors 10 Test Tank 11 Ozone Injector 11a On-off valve M Image data S test sample science fiction surface Cr crack Dx evaluation index Z Ozone

Claims

1. A system for evaluating ozone degradation of vulcanized rubber, comprising: a holding mechanism for holding a test sample of vulcanized rubber in an elongated state; a camera device for acquiring image data of the surface of said test sample; and a computing device for performing image processing of said image data, wherein an evaluation index for evaluating the degree of ozone degradation of said test sample is calculated by said computing device based on the results of said image processing, the holding mechanism has a holding portion for holding a number of the test samples; a moving mechanism for relatively moving at least one of the holding mechanism and the camera device, and a control unit for controlling the moving mechanism; the moving mechanism moves at least one of the holding mechanism and the camera device relative to one another, whereby each of the test samples held by the holding mechanism or the camera device is sequentially positioned at a predetermined photographing position at a predetermined elapsed time interval, and the image data of a front view of the surface of each of the test samples is acquired by the camera device at the predetermined photographing position; A system for evaluating ozone degradation of vulcanized rubber, which has a back plate placed on the back side of each of the test samples at the specified shooting position, and the difference in saturation in CIELAB color space between the color of the surface of each of the test samples in the image data and the color of the surface of the back plate is 20 or more.

2. A system for evaluating ozone degradation of vulcanized rubber, comprising: a holding mechanism for holding a test sample of vulcanized rubber in an elongated state; a camera device for acquiring image data of the surface of said test sample; and a computing device for performing image processing of said image data, wherein an evaluation index for evaluating the degree of ozone degradation of said test sample is calculated by said computing device based on the results of said image processing, the holding mechanism has a holding portion for holding a number of the test samples; a moving mechanism for relatively moving at least one of the holding mechanism and the camera device, and a control unit for controlling the moving mechanism; the moving mechanism moves at least one of the holding mechanism and the camera device relative to one another, whereby each of the test samples held by the holding mechanism or the camera device is sequentially positioned at a predetermined photographing position at a predetermined elapsed time interval, and the image data of a front view of the surface of each of the test samples is acquired by the camera device at the predetermined photographing position; A system for evaluating ozone degradation of vulcanized rubber, which has a back plate placed on the back side of each of the test samples at the specified shooting position, and the difference in lightness in CIELAB color space between the color of the surface of each of the test samples in the image data and the color of the surface of the back plate is 20 or more.

3. A system for evaluating ozone degradation of vulcanized rubber, comprising: a holding mechanism for holding a test sample of vulcanized rubber in an elongated state; a camera device for acquiring image data of the surface of said test sample; and a computing device for performing image processing of said image data, wherein an evaluation index for evaluating the degree of ozone degradation of said test sample is calculated by said computing device based on the results of said image processing, the holding mechanism has a holding portion for holding a number of the test samples; a moving mechanism for relatively moving at least one of the holding mechanism and the camera device, and a control unit for controlling the moving mechanism; the moving mechanism moves at least one of the holding mechanism and the camera device relative to one another, whereby each of the test samples held by the holding mechanism or the camera device is sequentially positioned at a predetermined photographing position at a predetermined elapsed time interval, and the image data of a front view of the surface of each of the test samples is acquired by the camera device at the predetermined photographing position; A system for evaluating ozone degradation of vulcanized rubber, comprising a back plate placed on the back side of each of the test samples at the predetermined photographing position, the reflectance of the surface of the back plate being 50% or less.

4. 4. The system for evaluating ozone degradation of vulcanized rubber according to claim 1, further comprising: an illumination means for irradiating light onto the surface of each of the test samples at the predetermined photographing position; and an angle formed between the optical axis direction of the light and the extending direction of the surface of the test sample is 10° or more and 80° or less.

5. The system for evaluating ozone degradation of vulcanized rubber according to any one of claims 1 to 4, further comprising a test tank in which the holding mechanism is installed, and each of the test samples held by the holding mechanism is placed in an atmosphere of a desired ozone concentration inside the test tank.

6. The system for evaluating ozone degradation of vulcanized rubber according to any one of claims 1 to 5, wherein at least one of the number, length, and contour length of ozone cracks generated on the surface of each of the test samples is calculated as the evaluation index.

7. A method for evaluating ozone degradation of vulcanized rubber, comprising the steps of: acquiring image data of the surface of a vulcanized rubber test sample held in an elongated state by a holding mechanism using a camera device; and calculating, by a computing device, an evaluation index for evaluating the degree of ozone degradation of the test sample based on the results of image processing of the acquired image data by the computing device, a holding mechanism for holding a large number of the test samples, and controlling the relative movement of at least one of the holding mechanism and the camera device to sequentially position each of the test samples held by the holding mechanism or the camera device at a predetermined photographing position at a predetermined elapsed time interval, and acquiring the image data of a front view of each of the test samples at the predetermined photographing position by the camera device; A method for evaluating ozone degradation of vulcanized rubber, in which a back plate is placed on the back side of each of the test samples at the specified shooting position, and the difference in saturation in CIELAB color space between the surface color of each of the test samples in the image data and the surface color of the back plate is made to be 20 or more, and / or the difference in lightness is made to be 20 or more.

8. A method for evaluating ozone degradation of vulcanized rubber, comprising the steps of: acquiring image data of the surface of a vulcanized rubber test sample held in an elongated state by a holding mechanism using a camera device; and calculating, by a computing device, an evaluation index for evaluating the degree of ozone degradation of the test sample based on the results of image processing of the acquired image data by the computing device, a holding mechanism for holding a large number of the test samples, and controlling the relative movement of at least one of the holding mechanism and the camera device to sequentially position each of the test samples held by the holding mechanism or the camera device at a predetermined photographing position at a predetermined elapsed time interval, and acquiring the image data of a front view of each of the test samples at the predetermined photographing position by the camera device; A method for evaluating ozone degradation of vulcanized rubber, comprising placing a back plate on the back side of each of the test samples at the predetermined photographing position, and setting the reflectance of the surface of the back plate to 50% or less.

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