A Visual Inspection Method and System for Pulley Dimensions

Abstract

The present invention relates to a method and system for visual inspection of pulley dimensions. The pulley is positioned and rotated one week with the axial center of the pulley as the center. During the rotation process, the following steps are executed every first angle: obtaining a front projection image of the pulley; detecting and obtaining the radius of a circle tangent to the inner groove angle of the front projection image of the pulley. If the radius is within the first threshold range, proceed to the next step; detecting and obtaining an arc corresponding to the outer groove angle of the front projection image of the pulley, and obtaining the radius of the circle corresponding to the arc. If the radius of the circle corresponding to the arc is within the second threshold range, proceed to the next step; fitting the sides of the groove angle through the coordinates of the edge pixels of the inner groove angle or the outer groove angle, obtaining the angular bisector of the inner groove angle according to the two sides of the groove angle, calculating the angular spacing between adjacent groove angles according to the angular bisector. If the angular spacing between adjacent groove angles is within the third threshold range, proceed to the next step; determining that the pulley is qualified.

Description

Technical Field

[0001] The present invention relates to the field of pulley size detection, and specifically refers to a visual detection method and system for pulley sizes. Background Art

[0002] Pulleys, belonging to disc hub parts, are mainly used in occasions for long-distance power transmission, such as the power output of small diesel engines, the power transmission of agricultural vehicles, tractors, automobiles, agricultural machinery, etc. As a power transmission system, the key of a pulley lies in the groove angle in contact with the belt and the center height of the installation reference. Therefore, after the pulley is manufactured, size detection is required, such as detecting parameters such as the tooth top, tooth bottom, groove angle, and the height of the groove angle of the pulley, to ensure the production quality. Only when the sizes of the pulley meet the preset range can the pulley be tightly engaged with the belt to prevent phenomena such as deviation and slipping.

[0003] The existing detection tools generally rely on manual or mechanical operation of tools such as scales for detection. The operation changes caused by the cost make the detection effect have certain fluctuations, and it is time-consuming and laborious, increasing the manpower.

[0004] Designing a visual detection method and system for pulley sizes to address the problems existing in the above-mentioned prior art is the purpose of the research of the present invention. Summary of the Invention

[0005] Aiming at the problems existing in the above-mentioned prior art, the present invention provides a visual detection method and system for pulley sizes, which can effectively solve the problems existing in the above-mentioned prior art.

[0006] The technical solution of the present invention is as follows:

[0007] A visual detection method for pulley sizes,

[0008] Locate the pulley and rotate it one week around the axis of the pulley. During the rotation process, the following steps are performed every first angle:

[0009] Obtain the orthographic projection image of the pulley;

[0010] Detect and obtain the radius of the circle tangent to the inner groove angle of the orthographic projection image of the pulley. If the radius is within the first threshold range, proceed to the next step;

[0011] Detect and obtain the arc corresponding to the outer groove angle of the orthographic projection image of the pulley, and obtain the radius of the circle corresponding to the arc. If the radius of the circle corresponding to the arc is within the second threshold range, proceed to the next step;

[0012] Fit the sides of the groove angle based on the coordinates of the edge pixels of the inner groove angle or the outer groove angle, obtain the angle bisector of the inner groove angle according to the two sides of the groove angle, calculate the angular pitch between adjacent groove angles, and if the angular pitch between adjacent groove angles is within the third threshold range, proceed to the next step;

[0013] Determine that the pulley is qualified.

[0014] Further, the fitting of the sides of the groove angle based on the coordinates of the edge pixels of the inner groove angle or the outer groove angle includes:

[0015] Obtain the coordinates of the edge pixels of the arc corresponding to the outer groove angle and the coordinates of the edge pixels of the groove angle, and fit the sides of the groove angle through the coordinates of the edge pixels of the arc corresponding to the outer groove angle and the coordinates of the edge pixels of the groove angle.

[0016] Further, after the step of if the angular pitch between adjacent groove angles is within the third threshold range, proceed to the next step and before the determination of being qualified, the following steps are further included:

[0017] Set a vertical fixed line in the orthographic projection image of the pulley, select an angle bisector that is farthest from the vertical fixed line, calculate the line pitch between an angle bisector that is farthest from the vertical fixed line and the vertical fixed line, and if the line pitch between adjacent groove angles is within the fourth threshold range, proceed to the next step.

[0018] Further, after the step of if the angular pitch between adjacent groove angles is within the third threshold range, proceed to the next step and before the determination of being qualified, the following steps are further included:

[0019] Frame the area between the groove angles in the orthographic projection image of the pulley;

[0020] Calculate the image area of the orthographic projection image of the pulley in the area between the groove angles, and if the image area is less than the fifth threshold, proceed to the next step.

[0021] Further, the framing of the area between the groove angles in the orthographic projection image of the pulley includes:

[0022] Set two horizontal fixed lines in the orthographic projection image of the pulley, one of the horizontal fixed lines is lower than any inner groove angle, and the other horizontal fixed line is higher than any outer groove angle;

[0023] Extend the angle bisector so that the angle bisector and the horizontal fixed line enclose a quadrilateral;

[0024] The calculation of the image area of the orthographic projection image of the pulley in the area between the groove angles includes:

[0025] Calculate the image area of the orthographic projection image of the pulley within the quadrilateral for the groove angle.

[0026] Furthermore, calculating the image area of the orthographic projection image of the pulley in the region between the groove angles includes:

[0027] Convert the orthographic projection image of the pulley into a grayscale image, calculate the number of pixels in the image of the region between the groove angles whose pixel grayscale values are greater than the sixth threshold, and calculate the image area of the orthographic projection image of the pulley in the region between the groove angles based on the number of pixels.

[0028] Furthermore, after the step of if the angular pitch between adjacent groove angles is within the range of the third threshold and then entering the next step, before the determination of being qualified, it further includes the following steps:

[0029] Calculate the angle corresponding to the angle formed by the sides of adjacent groove angles. If the angle is within the range of the seventh threshold, enter the next step.

[0030] Furthermore, a visual inspection system for pulley dimensions is provided, including:

[0031] A rotating mechanism for positioning the pulley and rotating it one week around the axial center of the pulley;

[0032] A photographing mechanism for obtaining the orthographic projection image of the pulley at intervals of the first angle during the rotation of the pulley;

[0033] An inner groove angle detection module for detecting and obtaining the radius of the circle tangent to the inner groove angle of the orthographic projection image of the pulley. If the radius is within the range of the first threshold, enter the next module;

[0034] An outer groove angle detection module for detecting and obtaining the circular arc corresponding to the outer groove angle of the orthographic projection image of the pulley, obtaining the radius of the circle corresponding to the circular arc. If the radius of the circle corresponding to the circular arc is within the range of the second threshold, enter the next module;

[0035] A groove angle pitch detection module for fitting the sides of the groove angle through the coordinates of the edge pixels of the inner groove angle or the outer groove angle, obtaining the angular bisector of the inner groove angle according to the two sides of the groove angle, calculating the angular pitch between adjacent groove angles according to the angular bisector. If the angular pitch between adjacent groove angles is within the range of the third threshold, enter the next module;

[0036] A determination module for determining that the pulley is qualified.

[0037] Therefore, the present invention provides the following effects and / or advantages:

[0038] In this application, an image of a pulley is obtained, and then various shapes in the pulley image are obtained through line recognition, circle recognition, and arc recognition in shape recognition respectively. Then, corresponding threshold comparisons are made using the parameters obtained through graphic recognition. Only when all parameters meet the parameter threshold range is it determined that the shape and size of the pulley are qualified.

[0039] In this application, the coordinates of the edge pixels of the arc corresponding to the outer groove angle and the coordinates of the edge pixels of the groove angle are used to fit the side of the groove angle, and a straight line closer to the side of the groove angle can be obtained.

[0040] In this application, the image area of the region between the groove angles in the orthographic projection image of the pulley of the groove angle is further calculated, which can overcome the problem that defects in the groove angle edge cannot be calculated after straight line fitting due to the unevenness caused by groove angle cutting.

[0041] It should be understood that the above summary and the following detailed description of the present invention are exemplary and explanatory, and are intended to provide further explanation of the present invention as claimed. Brief Description of the Drawings

[0042] Figure 1 It is a schematic flow chart of the method provided by the present invention.

[0043] Figure 2 It is a schematic structural diagram of the pulley.

[0044] Figure 3 It is a schematic orthographic projection diagram of the side of the pulley.

[0045] Figure 4 It is a schematic diagram of one of the results calculated by the method provided by the present invention.

[0046] Figure 5 It is a schematic diagram of the second result calculated by the method provided by the present invention.

[0047] Figure 6 For Figure 5 the enlarged view of the second groove angle.

[0048] Figure 7 It is the third result calculated by the method provided by the present invention and does not meet the parameter range. Detailed Description of the Embodiment

[0049] For the convenience of those skilled in the art to understand, the structure of the present invention will be further described in detail below in combination with the accompanying drawings: It should be understood that the steps mentioned in this embodiment, unless specifically stating their order, can be adjusted according to actual needs in terms of their front and back order, and can even be executed simultaneously or partially simultaneously.

[0050] Refer to Figure 1, a visual inspection method for pulley dimensions,

[0051] S1, Locate the pulley and rotate it one week with the axis of the pulley as the center. In this embodiment, the pulley can be of the structure as shown in Figure 2 . There are several groove angles on its side for meshing with the corresponding belt. In this embodiment, it can be positioned and rotated through a rotating mechanism. The rotating mechanism includes a workpiece positioning block with a magnet, a servo motor, a bearing, etc. The servo motor drives the workpiece positioning block to rotate at a constant speed, and the magnet in the workpiece positioning block can ensure that the pulley does not slip during the rotation process.

[0052] During the rotation process, the following steps are executed every first angle: In this embodiment, the first angle is 3°. In other embodiments, it can also be other angles. It can be considered that the smaller the first angle, the longer the period for completing the entire measurement, and the higher the measurement accuracy.

[0053] S2, Obtain the front projection image of the pulley; In this embodiment, it is photographed through a camera mechanism such as a camera to obtain a picture as shown in Figure 2 . The shooting angle is a front projection from the side, so that the side projection of the pulley forms a toothed image, reducing the overlapping shadows and other situations caused by other structures in the image.

[0054] S3, Detect and obtain the radius of the circle tangent to the inner groove angle of the front projection image of the pulley. If the radius is within the first threshold range, proceed to the next step;

[0055] In this step, the radius of the circle tangent to the inner groove angle can be detected through a circle detection algorithm. The circle detection algorithm can be the Hough circle detection algorithm. The circle detection algorithm is a prior art and not the core improvement step of this application, so it will not be elaborated here. Through this step, a circle tangent to each inner groove angle as shown in Figure 4 can be obtained, and then the radius of each circle can be directly obtained through the circle detection algorithm. For example, the radii of the tangent circles of the inner groove angles of the pulley shown in Figure 4 from left to right are 0.420, 0.430, 0.429, 0.431, 0.431, 0.403, 0.397 in mm. And the first threshold range can be set according to the specifications of the produced pulleys. In this application, the first threshold range is set to 0.390 - 0.440. It can be seen that the radii of the tangent circles in Figure 4 all meet the first threshold range, indicating that the dimensions of the inner groove angles corresponding to the pulley shown in Figure 4 meet the production requirements and can proceed to the next step.

[0056] S4. Detect and obtain the arc corresponding to the outer groove angle of the orthographic projection image of the pulley, and obtain the radius of the circle corresponding to the arc. If the radius of the circle corresponding to the arc is within the second threshold range, proceed to the next step;

[0057] In this step, the algorithm for detecting the arc can also be detected by the Hough transform. The arc detection algorithm is a prior art and not the core improvement step of this application, so it will not be elaborated here. On the basis that the inner groove angle is determined to be qualified in step S3, the outer groove angle is further determined. Since the shape of the outer groove angle is closer to an arc rather than a circle, an arc algorithm is used for detection in this step. For the detected arc, calculate according to the circle where the arc is located to obtain the radius of the circle corresponding to the arc. As Figure 4 shown, the radii of the circles corresponding to the arcs of the outer groove angles from left to right are 0.465, 0.469, 0.476, 0.493, 0.477, 0.463, with the unit of mm. Similarly, the second threshold range can be set according to the specifications of the produced pulleys. In this application, the second threshold range is set to 0.460 - 0.500. It can be seen that the radii of the tangent circles in Figure 4 all meet the second threshold range, indicating that Figure 4 the dimensions of the outer groove angles of the shown pulley meet the production requirements and can proceed to the next step.

[0058] S5. Fit the sides of the groove angle through the coordinates of the edge pixels of the inner groove angle or the outer groove angle, obtain the angle bisector of the inner groove angle according to the two sides of the groove angle, and calculate the angular spacing between adjacent groove angles according to the angle bisector. If the angular spacing between adjacent groove angles is within the third threshold range, proceed to the next step;

[0059] In this step, the sides of the groove angle are fitted by the algorithm of line fitting. The algorithm of line fitting can be the least squares method and other algorithms, which are not the core improvement steps of this application and will not be elaborated here. Through line fitting, the lines corresponding to the respective sides of the groove angle can be obtained, as Figure 4 shown. Then find the angle bisector in the included angle formed by the lines on both sides of the groove angle. In this step, the angular spacing between adjacent groove angles is calculated through the angle bisector. The reason is that if the angular spacing between the groove angles is calculated using the center of the circle obtained in step S3, then even if the groove angles are offset, distorted, etc., the calculated angular spacing between the groove angles by the center of the circle is still within the normal range, making it difficult to detect comprehensively. Through the angle bisector, the orientations of the respective groove angles can be well obtained, and then the spacing can be calculated. In this embodiment, both angle bisectors are straight lines, and the distance between the two angle bisectors is calculated through the following steps: calculate the distance from the midpoint of the first line segment to the line where the second line segment is located; or calculate the distance between the midpoints of the two line segments. This embodiment obtains as Figure 4The distances between the angle bisectors from left to right of the results are successively: 3.509, 3.546, 3.543, 3.521, 3.525, 3.531, with the unit being mm. Similarly, the third threshold range can be set according to the specifications of the pulley produced. In this application, the third threshold range is set to 3.500 - 3.550. It can be seen that the Figure 4 radii of the tangent circles in Figure 4 all meet the third threshold range, indicating that

[0060] Further, the fitting of the side of the groove angle through the coordinates of the edge pixels of the inner groove angle or the outer groove angle includes:

[0061] Obtain the coordinates of the edge pixels of the arc corresponding to the outer groove angle and the coordinates of the edge pixels of the groove angle, and fit the side of the groove angle through the coordinates of the edge pixels of the arc corresponding to the outer groove angle and the coordinates of the edge pixels of the groove angle.

[0062] This step is optimized according to the principle of the least squares method. The principle of the least squares method is to assume that a straight line can be expressed in the form of y = bx + a, where b is the slope and a is the intercept. The least squares method fits n points to minimize the overall error from the fitted straight line. The solution method is also very simple, which is to minimize the perpendicular error from each point to the straight line. In this step, the coordinates of the edge pixels of the arc corresponding to the outer groove angle are added. Since the edge of the outer groove angle is connected to the side of the groove angle, it can be considered that the pixel points on the edge of the outer groove angle are the pixel points of the side of the groove angle. At the same time, due to the unstable shape change and position at the edge of the outer groove angle and the side of the groove angle, when selecting the side of the groove angle, only the pixels in the middle part of the groove angle are often taken as the side of the groove angle, which brings a certain error. In this step, the coordinates of the edge pixels of the arc corresponding to the outer groove angle and the coordinates of the edge pixels of the groove angle are used as the input elements of the least squares method, and a straight line closer to the side of the groove angle can be obtained.

[0063] S6, Set a vertical fixed straight line in the orthographic projection image of the pulley, select an angle bisector that is farthest from the vertical fixed straight line, calculate the line spacing between an angle bisector that is farthest from the vertical fixed straight line and the vertical fixed straight line. If the line spacing between adjacent groove angles is within the fourth threshold range, then proceed to the next step.

[0064] As Figure 4 shown, the vertical fixed straight line is Figure 4The rightmost straight line in [description], which can be set arbitrarily as long as it is vertical and has a fixed position. The function of setting this vertical and fixed straight line is to calculate the angle bisector of the first inner groove angle or outer groove angle, that is, the distance from the orientation direction of the first inner groove angle or outer groove angle to this fixed straight line, so as to calculate whether the width of the overall groove angle is within the preset range. Similarly, the fourth threshold range can be set according to the specifications of the pulley produced. In this application, the fourth threshold range is set to 26.200 - 26.500 mm. It can be seen that the Figure 4 radii of the tangent circles in [description] all meet the fourth threshold range, indicating that Figure 4 the total width of the groove angle corresponding to the pulley shown in [description] meets the production requirements and can enter the next step.

[0065] S7. Select the area between the groove angles in the orthographic projection image of the pulley;

[0066] Calculate the image area of the area between the groove angles in the orthographic projection image of the pulley. If the image area is less than the fifth threshold, enter the next step.

[0067] Specifically, it includes:

[0068] S7.1. Set two horizontal fixed straight lines in the orthographic projection image of the pulley, where one horizontal fixed straight line is lower than any inner groove angle and the other horizontal fixed straight line is higher than any outer groove angle; as shown in Figure 5 [description].

[0069] S7.2. Extend the angle bisector so that the angle bisector and the horizontal fixed straight line enclose a quadrilateral; the quadrilateral enclosed by one angle bisector and the horizontal fixed straight line is shown as the shaded part in Figure 5 [description].

[0070] S7.3. Convert the orthographic projection image of the pulley into a grayscale image, calculate the number of pixels with pixel grayscale values greater than the sixth threshold in the image of the area between the groove angles, and calculate the image area of the area between the groove angles in the orthographic projection image of the pulley according to the number of pixels.

[0071] In this step, since the groove angles of the pulley are obtained by cutting, if there are problems such as notches in the cutting tool, then the groove angles will be serrated after cutting, as shown in Figure 6 [description], where Figure 6 is Figure 5An enlarged view of the area between the second groove corner. Since the present application adopts a straight line fitting method to fit a straight line, and the jagged unqualified area has a convex or concave shape, the fitted straight line calculated by this image, the convex or concave pixels in the least squares fitting process, the error from the pixel point to the straight line is also the smallest, so it is necessary to add step S7, and further test if step S6 is judged to be qualified. After the image is converted into a grayscale image, each pixel has a grayscale value. In order to reasonably reduce the influence of edge blur during image capture, the sixth threshold of the present application is set to 50, that is, pixels with a grayscale value greater than 50 are considered to be gaps in the groove corners. By calculating the number of pixels with a grayscale value greater than 50, the area with a grayscale value greater than 50 can be obtained, and it is judged whether the area is greater than the fifth threshold. The fifth threshold is set to 1 in the present application. According to Figure 5 It can be seen that the area of ​​the second groove corner with a gray value greater than 50 is 3.353mm 2 , which is unqualified.

[0072] S8, calculating the angle corresponding to the angle formed by the sides of adjacent groove angles, and if the angle is within the seventh threshold range, proceeding to the next step.

[0073] In this step, refer to Figure 4 , the angles of each groove from left to right are 39.590°, 39.768°, 39.590°, 39.683°, 39.928°, 40.004°, and 40.172°, respectively. The seventh threshold range of this step is 39.5°-40.3°. Figure 4 The groove angles in the table meet production requirements. Figure 7 The angle of the first groove angle shown in the figure is 39.313°, which is not within the seventh threshold range, and is judged as unqualified. At the same time, the distance from the direction of the first inner groove angle to the fixed straight line is 27.026mm, which is not within the third threshold range and is also judged as unqualified.

[0074] S9, judging whether the pulley is qualified. In the case that all the judgments in the above steps are passed, this step outputs a signal that the pulley is qualified.

[0075] A pulley size visual inspection system is further provided, comprising:

[0076] The rotating mechanism is used to position the pulley and rotate the pulley one circle around the axial direction of the pulley;

[0077] A shooting mechanism, used for acquiring an orthographic projection image of the pulley at every first angle during the rotation of the pulley;

[0078] Inner groove angle detection module, which is used to detect and obtain the radius of the circle tangent to the inner groove angle of the orthographic projection image of the pulley. If the radius is within the first threshold range, it proceeds to the next module;

[0079] Outer groove angle detection module, which is used to detect and obtain the arc corresponding to the outer groove angle of the orthographic projection image of the pulley, obtain the radius of the circle corresponding to the arc. If the radius of the circle corresponding to the arc is within the second threshold range, it proceeds to the next module;

[0080] Groove angle spacing detection module, which is used to fit the sides of the groove angle through the coordinates of the edge pixels of the inner groove angle or the outer groove angle, obtain the angular bisector of the inner groove angle according to the two sides of the groove angle, calculate the angular spacing between adjacent groove angles according to the angular bisector. If the angular spacing between adjacent groove angles is within the third threshold range, it proceeds to the next module;

[0081] Determination module, which is used to determine that the pulley is qualified.

[0082] Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can adopt the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0083] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0084] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured product including an instruction device, and the instruction device implements the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0085] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are executed on the computer or other programmable apparatus to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable apparatus provide steps for realizing the functions specified in one process or a plurality of processes and / or boxes. Figure 1 One process or a plurality of processes and / or boxes Figure 1 Steps for realizing the functions specified in one box or a plurality of boxes.

[0086] It should be noted that, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of other elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention can be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim listing several means, several of these means can be embodied by the same item of hardware. The use of the words first, second, and third, etc. does not denote any order. These words can be interpreted as names.

[0087] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made by those skilled in the art once they learn the basic inventive concept. Therefore, the appended claims are intended to be construed to cover the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0088] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

[0089] In the present invention, unless otherwise clearly specified and defined, terms such as "install", "connect", "connection", "fix", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0090] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

Claims

1. A visual inspection method for pulley dimensions, characterized in that: Locate the pulley and rotate it once around the axis of the pulley. During the rotation process, perform the following steps every first angle: Obtain the orthographic projection image of the pulley; Detect and obtain the radius of the circle tangent to the inner groove angle of the orthographic projection image of the pulley. If the radius is within the first threshold range, proceed to the next step; Detect and obtain the arc corresponding to the outer groove angle of the orthographic projection image of the pulley, and obtain the radius of the circle corresponding to the arc. If the radius of the circle corresponding to the arc is within the second threshold range, proceed to the next step; Fit the sides of the groove angle through the coordinates of the edge pixels of the inner groove angle or the outer groove angle. Obtain the angle bisector of the inner groove angle according to the two sides of the groove angle, and calculate the angular spacing between adjacent groove angles according to the angle bisector. If the angular spacing between adjacent groove angles is within the third threshold range, proceed to the next step; Determine that the pulley is qualified; After the step of "if the angular spacing between adjacent groove angles is within the third threshold range, proceed to the next step" and before the determination of being qualified, the following steps are further included: Frame the area between the groove angles in the orthographic projection image of the pulley; Calculate the image area of the area between the groove angles in the orthographic projection image of the pulley. If the image area is less than the fifth threshold, proceed to the next step; The step of "framing the area between the groove angles in the orthographic projection image of the pulley" includes: Set two horizontal fixed lines in the orthographic projection image of the pulley, one of the horizontal fixed lines is lower than any inner groove angle, and the other horizontal fixed line is higher than any outer groove angle; Extend the angle bisector so that the angle bisector and the horizontal fixed line enclose a quadrilateral; The step of "calculating the image area of the area between the groove angles in the orthographic projection image of the pulley" includes: Calculate the image area of the orthographic projection image of the pulley within the quadrilateral.

2. The visual inspection method for the size of a pulley according to claim 1, wherein: Fitting the sides of the groove angle through the coordinates of the edge pixels of the inner groove angle or the outer groove angle includes: Obtain the coordinates of the edge pixels of the arc corresponding to the outer groove angle and the coordinates of the edge pixels of the groove angle, and fit the sides of the groove angle through the coordinates of the edge pixels of the arc corresponding to the outer groove angle and the coordinates of the edge pixels of the groove angle.

3. The visual inspection method for pulley dimensions according to claim 1, wherein: After the step of "if the angular spacing between adjacent groove angles is within the third threshold range, proceed to the next step" and before the determination of being qualified, the following steps are further included: Set a vertical fixed line in the orthographic projection image of the pulley, select an angle bisector farthest from the vertical fixed line, and calculate the line spacing between the angle bisector farthest from the vertical fixed line and the vertical fixed line. If the line spacing between adjacent groove angles is within the fourth threshold range, proceed to the next step.

4. A visual inspection method for the size of a pulley according to claim 1, characterized in that: The step of "calculating the image area of the area between the groove angles in the orthographic projection image of the pulley" includes: Convert the orthographic projection image of the pulley into a grayscale image, calculate the number of pixels whose pixel gray value is greater than the sixth threshold in the image of the area between the groove angles, and calculate the image area of the area between the groove angles in the orthographic projection image of the pulley according to the number of pixels.

5. A visual inspection method for pulley dimensions according to claim 1, characterized in that: If the angular pitch between adjacent groove angles is within the third threshold range, after entering the next step and before the determination of being qualified, the following steps are further included: Calculate the angle corresponding to the angle formed by the sides of adjacent groove angles. If the angle is within the seventh threshold range, enter the next step.

6. A visual inspection system for pulley dimensions, characterized in that: Including: A rotating mechanism for positioning the pulley and rotating one week with the axis of the pulley as the center; A photographing mechanism for obtaining a front projection image of the pulley at every first angle during the rotation of the pulley; An inner groove angle detection module for detecting and obtaining the radius of the circle tangent to the inner groove angle of the front projection image of the pulley. If the radius is within the first threshold range, enter the next module; An outer groove angle detection module for detecting and obtaining the arc corresponding to the outer groove angle of the front projection image of the pulley, and obtaining the radius of the circle corresponding to the arc. If the radius of the circle corresponding to the arc is within the second threshold range, enter the next module; A groove angle pitch detection module for fitting the sides of the groove angle through the coordinates of the edge pixels of the inner or outer groove angle, obtaining the angular bisector of the inner groove angle according to the two sides of the groove angle, and calculating the angular pitch between adjacent groove angles according to the angular bisector. If the angular pitch between adjacent groove angles is within the third threshold range, enter the next module; A determination module for determining that the pulley is qualified; If the angular pitch between adjacent groove angles is within the third threshold range, after entering the next step and before the determination of being qualified, the following steps are further included: Select the area between the groove angles in the front projection image of the pulley; Calculate the image area of the area between the groove angles in the front projection image of the pulley. If the image area is less than the fifth threshold, enter the next step; The selection of the area between the groove angles in the front projection image of the pulley includes: Set two horizontal fixed lines in the front projection image of the pulley, one of the horizontal fixed lines is lower than any inner groove angle, and the other horizontal fixed line is higher than any outer groove angle; Extend the angular bisector so that the angular bisector and the horizontal fixed line enclose a quadrilateral; The calculation of the image area of the area between the groove angles in the front projection image of the pulley includes: Calculate the image area of the front projection image of the pulley within the quadrilateral.

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