A joint detection method for surface defects of metal components

Abstract

The present invention provides a combined detection method for metal component surface defects, which relates to the field of metal detection and includes: step S1, workpiece placement; step S2, eddy current testing; step S3, workpiece transfer; step S4, visual inspection; and step S5, workpiece judgment. This method combines eddy current and machine vision to analyze and judge the surface defects of thin-walled tubular or cylindrical metal components. This effectively addresses the problems of single machine vision detection methods being unable to accurately and quickly detect surface defects of such metal components, prone to detection blind spots, and single eddy current flaw detection being insensitive, quantitatively inaccurate, and susceptible to signal interference. This method achieves efficient, accurate, and comprehensive surface flaw detection of metal components.

Description

Technical Field

[0001] The present invention relates to the technical field of metal detection, and in particular to a combined detection method for surface defects of metal components. Background Art

[0002] Metal surface defects refer to discontinuous, irregular, or non-compliant areas that appear on the surface of metal materials during processing or use, including scratches, pits, pores, cracks, inclusions, etc. Metal surface defects can easily lead to reduced metal strength, weakened toughness, poor fatigue performance, accelerated corrosion, and other problems. At present, the detection of metal surface defects mainly relies on manual inspection and machine vision inspection: Manual inspection, that is, manual inspection using relevant inspection tools to inspect metal surface defects. This method is difficult and inefficient, with low detection accuracy and large errors, and is greatly affected by human factors; machine vision inspection, that is, converting the target to be inspected into an image signal through an image capture device, transmitting it to a dedicated image processing system, and converting it into a digital signal based on pixel distribution, brightness, color and other information. The defects on the metal surface are identified, analyzed, and judged through the digital signal and set thresholds to achieve the purpose of accurate detection. However, for some thin-walled tubular and cylindrical metal components, it is necessary not only to detect defects or damage on their surfaces, but also to detect defects or damage near their surfaces in order to effectively analyze the damage situation of the metal components and achieve the purpose of accurately detecting component defects. Although machine vision inspection can detect tiny surface defects with high sensitivity, it cannot detect embedded defects near the surface of thin-walled tubular and cylindrical metal components, resulting in incomplete surface flaw detection of such metal components, prone to detection blind spots, and unable to accurately, efficiently and completely realize the analysis and judgment of defects of such metal components. Summary of the Invention

[0003] In response to the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a joint detection method for surface defects of metal components. This method combines eddy current and machine vision to analyze and judge the surface defects of thin-walled tubular or cylindrical structure metal components, effectively solving the problem that a single machine vision detection method cannot accurately and quickly detect the surface defects of such metal components and is prone to detection blind spots.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A combined detection method for metal component surface defects, targeting thin-walled tubular and cylindrical metal components, comprises:

[0006] Step S1, workpiece placement: metal components are placed on a conveying mechanism in sequence. An eddy current detection module and a visual detection module are respectively provided on one side of the conveying mechanism to facilitate eddy current detection and visual detection of the metal components in sequence;

[0007] Step S2, eddy current testing: The metal component is moved to the eddy current testing module. While the metal component rotates around its own axis, eddy current testing is performed on the outer and inner surfaces of the metal component using an outer diameter eddy current probe and an inner diameter eddy current probe. During the testing process, the outer diameter eddy current probe and the inner diameter eddy current probe move simultaneously along the axis of the metal component.

[0008] Step S3, workpiece transfer: according to the eddy current test results, unqualified products are transferred to the unqualified area, and qualified products are transferred to the visual inspection module;

[0009] Step S4, visual inspection: While the qualified eddy current test product is rotating around its own axis, the outer diameter visual probe is activated to perform visual inspection on the outer surface of the metal component. During the inspection process, the outer diameter visual probe moves along the axis of the metal component. Afterwards, the metal component stops rotating, and the inner diameter visual probe is activated and moved along the axis of the metal component to perform visual inspection on the inner surface of the metal component.

[0010] Step S5, workpiece judgment: first transfer the unqualified products detected by visual inspection to the unqualified area; then make a joint judgment on the qualified products detected by visual inspection, transfer the unqualified products detected by joint judgment to the unqualified area, and transfer the qualified products to the conveying mechanism for the next step.

[0011] Based on further optimization of the above scheme, during the eddy current detection process of step S2, the distance between the end of the outer diameter eddy current probe and the outer surface of the metal component is 1 to 5 mm, and the distance between the end of the inner diameter eddy current probe and the inner surface of the metal component is 1 to 5 mm.

[0012] Based on further optimization of the above solution, the specific steps of eddy current detection in step S2 are:

[0013] Step S21: Scan the outer surface and inner surface of the metal component line by line along the axis direction using the outer diameter eddy current probe and the inner diameter eddy current probe to obtain eddy current signal acquisition signals;

[0014] Step S22, filtering processing: First, the time domain signal in the eddy current signal acquisition signal is processed to obtain the localized spectrum:

[0015]

[0016] Where: represents a time series signal, w represents a real frequency variable;

[0017] Then, the filtering interval is delineated and the harmonic components outside the filtering interval are reset to zero;

[0018] Finally, the filtered frequency domain signal is converted into a time domain signal:

[0019]

[0020] Step S23: Extract the peak value of the signal after filtering and set the eddy current defect threshold F d If the extracted signal peak is not less than the eddy current defect threshold, the metal component is judged to be unqualified; if the extracted signal peak is less than the eddy current defect threshold, the metal component is judged to be qualified, and the corresponding qualified product eddy current peak F is recorded.

[0021] Based on further optimization of the above solution, the filtering range is 0 to 7 MHz.

[0022] Based on further optimization of the above scheme, during the visual inspection process of step S4, the distance between the end of the outer diameter visual probe and the corresponding outer surface of the metal component is 20 to 50 mm; the inner diameter visual probe is collinear with the central axis of the data component, and during the inspection process, the inner diameter visual probe moves from the outside to the inside of the metal component (that is, initially, the inner diameter visual probe is located outside the metal component).

[0023] Based on further optimization of the above solution, the specific steps of the visual inspection in step S4 are as follows:

[0024] Step S41: Scan the outer surface and inner surface of the metal component line by line along the axis direction using an outer diameter visual probe and an inner diameter visual probe to obtain a visual signal acquisition image;

[0025] Step S42: Image processing:

[0026] First, the visual signal acquisition image is grayed to obtain a grayscale image. The grayscale value of each pixel in the image for:

[0027]

[0028] Where: R i 、G i 、B i Respectively represent i The color values ​​of the red channel, green channel, and blue channel of each pixel; Represent the weight coefficients of the color values ​​corresponding to the red channel, green channel, and blue channel respectively;

[0029] Afterwards, the grayscale image is denoised:

[0030]

[0031] Where:(x,y) Indicates the coordinates of the corresponding pixel point; represents the standard deviation;

[0032] Then, the Sobel operator is used to perform edge detection on the grayscale image after denoising, and the area surrounded by the upper edge, lower edge, left edge and right edge is divided out to obtain the target image, and the rest of the image is removed as invalid background.

[0033] Finally, set the binarization threshold T , perform binarization on the target image to obtain a binary image:

[0034] like Gray(i)≥T , then the grayscale value of the pixel is 255, if Gray(i)< T , then the gray value of the pixel is 0;

[0035] Step S43: Compare the obtained binary image with the preset standard defect binary image point by point. If the pixel matches, the pixel is marked as "1" and the coordinates of the corresponding pixel are obtained. (x i ,y i ) , otherwise it is recorded as "0";

[0036] Get the center point of all pixels marked as "1" (x 0 ,y 0 ) :

[0037]

[0038] Center point (x 0 ,y 0 ) is the center of the circle, r A circular frame is drawn around the pixels marked as "1" with a radius of 0.001. If the number of pixels marked as "1" in the circular frame exceeds 2 / 3 of the area of ​​the corresponding circular frame, the area is judged as a defect; otherwise, it is not judged as a defect.

[0039] Count the number and area of ​​all areas judged as defects and preset the defect area threshold S d Defect count threshold N d If the total area of ​​the defective regions detected is not less than the defect area threshold and / or the number of defects is not less than the defect number threshold, the corresponding metal component is judged to be unqualified, and the total defect area S and the number of defects N are recorded; otherwise, the metal component is judged to be qualified.

[0040] Based on the further optimization of the above scheme, ther It is 0.5 to 5 mm and is determined according to the scanning rate.

[0041] Based on the further optimization of the above solution, the joint judgment in step S5 is specifically to obtain the joint judgment value of eddy current detection and visual detection P :

[0042]

[0043] Where: a represents the eddy current peak equivalent, b Indicates the visual defect area equivalent, c Indicates the equivalent number of visual defects;

[0044] Preset joint judgment threshold P d If the joint judgment value is not less than the joint judgment threshold, the corresponding metal component is judged to be unqualified; otherwise, it is judged to be qualified.

[0045] The following are the technical effects of the solution of the present invention:

[0046] This application combines the methods of first performing eddy current testing and then performing visual inspection, and through the complementary advantages of eddy current testing and visual inspection, effectively avoids the problems of single eddy current testing being insensitive to surface defects of metal components, inaccurate quantitative detection, and being susceptible to signal interference, as well as the inability of single visual inspection to detect defects below the surface and near-surface defects of metal components, thereby achieving zero-blind zone detection of surface and near-surface defects of metal components, avoiding detection blind spots, and improving detection accuracy and efficiency. This application integrates eddy current and visual inspection data to avoid the errors of a single detection method and improve the reliability and confidence of detection data. Secondly, it expands the detection range and avoids detection blind spots. Thirdly, it improves detection efficiency and avoids the time-consuming and labor-intensive problems of multiple inspections, thereby effectively saving labor productivity and reducing production intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a flowchart of the combined eddy current and visual detection process in an embodiment of the present invention.

[0048] Figure 2 Schematic diagram of the structure of the joint detection system in Example 3 of the present invention.

[0049] Among them, 10. Conveying mechanism; 21. First rotating seat; 22. Servo drive mechanism for outer diameter eddy current probe; 23. Servo drive mechanism for inner diameter eddy current probe; 24. Outer diameter eddy current probe; 25. Inner diameter eddy current probe; 31. Second rotating seat; 32. Servo drive mechanism for outer diameter visual probe; 33. Servo drive mechanism for inner diameter visual probe; 34. Outer diameter visual probe; 35. Inner diameter visual probe; 41. Column; 42. First steering knuckle; 43. Second steering knuckle; 44. Gripper lifter; 45. Gripper; 50. Unqualified frame. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0051] Example 1:

[0052] A combined detection method for metal component surface defects, targeting thin-walled tubular and cylindrical metal components, comprises:

[0053] Step S1, workpiece placement: metal components are placed on a conveying mechanism in sequence. An eddy current detection module and a visual detection module are respectively provided on one side of the conveying mechanism to facilitate eddy current detection and visual detection of the metal components in sequence;

[0054] Step S2, eddy current testing: the metal component is moved to the eddy current testing module. While the metal component rotates about its own axis, eddy current testing is performed on the outer and inner surfaces of the metal component using an outer diameter eddy current probe and an inner diameter eddy current probe at the same time. During the testing process, the distance between the end of the outer diameter eddy current probe and the outer surface of the metal component is 1 to 5 mm (preferably 3 mm), and the distance between the end of the inner diameter eddy current probe and the inner surface of the metal component is 1 to 5 mm (preferably 3 mm), and the outer diameter eddy current probe and the inner diameter eddy current probe are moved simultaneously along the axis of the metal component (the speed at which the outer diameter eddy current probe and the inner diameter eddy current probe move along the axis of the metal component matches the speed at which the metal component rotates about its own axis, ensuring that the eddy current testing process covers a wide area);

[0055] The specific steps of eddy current testing are:

[0056] Step S21: Scan the outer surface and inner surface of the metal component line by line along the axis direction using the outer diameter eddy current probe and the inner diameter eddy current probe to obtain eddy current signal acquisition signals;

[0057] Step S22, filtering processing: First, the time domain signal in the eddy current signal acquisition signal is processed to obtain the localized spectrum:

[0058]

[0059] Where: represents a time series signal, w represents a real frequency variable;

[0060] Then, the filtering interval is delineated and the filtering interval is 0 to 7 MHz (the specific filtering range is set according to the actual situation), and the harmonic components outside the filtering interval are reset to zero;

[0061] Finally, the filtered frequency domain signal is converted into a time domain signal:

[0062]

[0063] Step S23: Extract the peak value of the signal after filtering and set the eddy current defect threshold F d (Eddy current defect threshold F d (obtained from a large amount of laboratory empirical data), if the extracted signal peak is not less than the eddy current defect threshold, the metal component is judged to be unqualified; if the extracted signal peak is less than the eddy current defect threshold, the metal component is judged to be qualified, and the corresponding qualified product eddy current peak F is recorded.

[0064] Step S3, workpiece transfer: according to the eddy current test results, unqualified products are transferred to the unqualified area, and qualified products are transferred to the visual inspection module;

[0065] Step S4, visual inspection: while the qualified eddy current test product rotates around its own axis, the outer diameter visual probe is started to perform visual inspection on the outer surface of the metal component. During the inspection process, the distance between the end of the outer diameter visual probe and the corresponding outer surface of the metal component is 20 to 50 mm (preferably 35 mm), and the outer diameter visual probe moves along the axis of the metal component (the speed of the outer diameter visual probe moving along the axis of the metal component matches the speed of the metal component rotating around itself, ensuring that the outer diameter visual probe can capture clear images without ghosting). Afterwards, the metal component stops rotating, and the inner diameter visual probe is started and moved along the axis of the metal component to perform visual inspection on the inner surface of the metal component. The inner diameter visual probe is collinear with the central axis of the data component, and during the inspection process, the inner diameter visual probe moves from the outside to the inside of the metal component (i.e., initially, the inner diameter visual probe is located outside the metal component).

[0066] The specific steps of visual inspection are:

[0067] Step S41: Scan the outer surface and inner surface of the metal component line by line along the axis direction using an outer diameter visual probe and an inner diameter visual probe to obtain a visual signal acquisition image;

[0068] Step S42: Image processing:

[0069] First, the visual signal acquisition image is grayed to obtain a grayscale image. The grayscale value of each pixel in the image for:

[0070]

[0071] Where: R i 、G i 、B i Respectively represent i The color values ​​of the red channel, green channel, and blue channel of each pixel; Respectively represent the weight coefficients of the color values ​​corresponding to the red channel, green channel, and blue channel. In this embodiment, , which proves that the green channel has the highest sensitivity, the red channel is second, and the blue channel is the lowest;

[0072] Afterwards, the grayscale image is denoised:

[0073]

[0074] Where: (x,y) Indicates the coordinates of the corresponding pixel point; represents the standard deviation;

[0075] Then, the Sobel operator is used to perform edge detection on the grayscale image after denoising, and the area surrounded by the upper edge, lower edge, left edge and right edge is divided out to obtain the target image, and the rest of the image is removed as invalid background.

[0076] Finally, set the binarization threshold T (Binarization threshold T Obtained from a large amount of laboratory empirical data), the target image is binarized to obtain a binary image:

[0077] like Gray(i)≥T , then the grayscale value of the pixel is 255, if Gray(i)< T , then the gray value of the pixel is 0;

[0078] Step S43: Compare the obtained binary image with the preset standard defect binary image point by point. If the pixel matches, the pixel is marked as "1" and the coordinates of the corresponding pixel are obtained. (x i ,y i ) , otherwise it is recorded as "0";

[0079] Get the center point of all pixels marked as "1" (x 0 ,y 0 ) :

[0080]

[0081] Center point (x 0 ,y 0 ) is the center of the circle, r The pixel points marked as "1" are circled with a radius of r The range is 0.5 to 5 mm, determined by the scanning rate. If the number of pixels marked as "1" in the circular frame exceeds 2 / 3 of the area of ​​the corresponding circular frame, the area is judged to be a defect. Otherwise, it is not judged as a defect.

[0082] Count the number and area of ​​all areas judged as defects and preset the defect area threshold S d Defect count threshold N d (Defect area threshold S d , defect quantity threshold N d (obtained from a large amount of empirical data in the laboratory), if the total area of ​​the defective regions detected is not less than the defect area threshold and / or the number of defects is not less than the defect number threshold, the corresponding metal component is judged to be unqualified, and the total defect area S and the number of defects N are recorded; otherwise, the metal component is judged to be qualified.

[0083] Step S5, workpiece judgment: first transfer the unqualified products of visual inspection to the unqualified area; then make a joint judgment on the qualified products of visual inspection, specifically: obtain the joint judgment value of eddy current inspection and visual inspection P :

[0084]

[0085] Where: a represents the eddy current peak equivalent, b Indicates the visual defect area equivalent, c Indicates the equivalent number of visual defects (a, b, c are obtained from a large amount of laboratory experience data);

[0086] Preset joint judgment threshold P d (Joint judgment threshold P d (obtained from a large amount of laboratory experience data), if the joint judgment value is not less than the joint judgment threshold, the corresponding metal component is judged to be unqualified, otherwise it is judged to be qualified.

[0087] Unqualified products are jointly judged and transferred to the unqualified area, and qualified products are transferred to the conveying mechanism for the next operation.

[0088] Example 2:

[0089] As another preferred embodiment of the present application, based on the solution in Example 1, the specific method for performing area statistics on all regions determined to be defects in step S43 is as follows:

[0090] First, the defect area is treated as an approximate quadrilateral, and the four directions of distance from the pixel center point - point O are obtained by Euclidean distance. (x 0 ,y 0 ) The farthest pixel coordinates: A ( x A ,y A )、B( x B ,y B )、C( x C ,y C )、B( x D ,y D ),

[0091]

[0092] Then, the quadrilateral of the defect area is divided into four triangles: OAB, OBC, OCD, and OAD, and the areas of the four triangles are calculated by the vector method. M A 、M B 、M C 、M D ,For example:

[0093]

[0094] After that, get the total area of ​​the quadrilateral M :

[0095]

[0096] And obtain the number of all pixels Z0 in the quadrilateral frame and the number of pixels corresponding to the defect area in the quadrilateral frame Z i , finally, the area of ​​the defect area is obtained M i :

[0097] .

[0098] Example 3:

[0099] A combined detection system based on eddy current and machine vision, using the detection method in Example 1 or Example 2, with reference to Figure 2 As shown: it includes a conveying mechanism 10, an eddy current detection module, a visual inspection module, a transfer robot and an unqualified frame 50, the eddy current detection module and the visual inspection module are arranged on the same side of the conveying mechanism 10 and the transfer robot is arranged between the eddy current detection module and the visual inspection module, and the unqualified frame 50 is arranged on the side of the transfer robot away from the conveying mechanism;

[0100] The conveying mechanism 10 adopts a conventional conveying production line (which can adopt a conveyor belt or other conveying methods) to transport the metal components to be inspected and the qualified metal components;

[0101] The eddy current detection module includes a first rotating seat 21, an outer diameter eddy current probe servo drive mechanism 22, an inner diameter eddy current probe servo drive mechanism 23, an outer diameter eddy current probe 24 and an inner diameter eddy current probe 25, wherein the first rotating seat 21 is fixedly arranged on the ground corresponding to the transmission mechanism 10 for supporting and rotating the metal component; the outer diameter eddy current probe servo drive mechanism 22 and the inner diameter eddy current probe servo drive mechanism 23 are arranged on the side of the first rotating seat 21 away from the transfer manipulator (such as Figure 2 As shown), the outer diameter eddy current probe servo drive mechanism 22 installs the outer diameter eddy current probe 24 through a mechanical arm, and the inner diameter eddy current probe servo drive mechanism 23 installs the inner diameter eddy current probe 25 through a mechanical arm (the mechanical arm can be a conventional mechanical arm, and the three-dimensional movement of the outer diameter eddy current probe 24 and the inner diameter eddy current probe 25 needs to be ensured), thereby respectively realizing the three-dimensional spatial movement of the outer diameter eddy current probe 24 and the inner diameter eddy current probe 25;

[0102] The visual inspection module includes a second rotating seat 31, an outer diameter visual probe servo drive mechanism 32, an inner diameter visual probe servo drive mechanism 33, an outer diameter visual probe 34 and an inner diameter visual probe 35, wherein the second rotating seat 31 is fixedly arranged on the ground corresponding to the conveying mechanism 10 for supporting and rotating the metal component; the outer diameter visual probe servo drive mechanism 32 and the inner diameter visual probe servo drive mechanism 33 are arranged on the side of the second rotating seat 31 away from the transfer robot (such as Figure 2As shown), the outer diameter vision probe servo drive mechanism 32 installs the outer diameter vision probe 34 through a robotic arm, and the inner diameter vision probe servo drive mechanism 33 installs the inner diameter vision probe 35 through a robotic arm (the robotic arm can be a conventional robotic arm, and the three-dimensional movement of the outer diameter vision probe 34 and the inner diameter vision probe 35 needs to be ensured), thereby respectively realizing the three-dimensional spatial movement of the outer diameter vision probe 34 and the inner diameter vision probe 35;

[0103] The transfer robot includes a column 41, a first steering knuckle 42, a second steering knuckle 43, a gripper lifter 44 and a gripper 45. The column 41 is fixed on the ground, the first steering knuckle 42 is rotatably mounted on the column 41, the second steering knuckle 43 is rotatably mounted on the end of the first steering knuckle 42 away from the column 41, the gripper lifter 44 is slidably mounted on the end of the second steering knuckle 43 away from the first steering knuckle 42, and the gripper 45 is fixedly mounted on the bottom end of the gripper lifter 44 (such as Figure 2 shown);

[0104] The unqualified frame 50 is made of cold-rolled sheet metal and is used to store the screened unqualified products.

Claims

1. A method for joint detection of surface defects of metal components, characterized by: include: Step S1, workpiece placement: metal components are placed on a conveying mechanism in sequence, and an eddy current detection module and a visual detection module are respectively set on one side of the conveying mechanism; Step S2, eddy current testing: The metal component is moved to the eddy current testing module. While the metal component rotates around its own axis, eddy current testing is performed on the outer and inner surfaces of the metal component using an outer diameter eddy current probe and an inner diameter eddy current probe. During the testing process, the outer diameter eddy current probe and the inner diameter eddy current probe move simultaneously along the axis of the metal component. The specific steps of eddy current testing are: Step S21: Scan the outer surface and inner surface of the metal component line by line along the axis direction using the outer diameter eddy current probe and the inner diameter eddy current probe to obtain eddy current signal acquisition signals; Step S22, filtering processing: First, the time domain signal in the eddy current signal acquisition signal is processed to obtain the localized spectrum: Where: represents a time series signal, w represents a real frequency variable; Then, the filtering interval is delineated and the harmonic components outside the filtering interval are reset to zero; Finally, the filtered frequency domain signal is converted into a time domain signal: Step S23: Extract the peak value of the signal after filtering and set the eddy current defect threshold F d If the extracted signal peak value is not less than the eddy current defect threshold, the metal component is judged to be unqualified; if the extracted signal peak value is less than the eddy current defect threshold, the metal component is judged to be qualified, and the corresponding qualified product eddy current peak value F is recorded; Step S3, workpiece transfer: according to the eddy current test results, unqualified products are transferred to the unqualified area, and qualified products are transferred to the visual inspection module; Step S4, visual inspection: While the qualified eddy current test product is rotating around its own axis, the outer diameter visual probe is activated to perform visual inspection on the outer surface of the metal component. During the inspection process, the outer diameter visual probe moves along the axis of the metal component. Afterwards, the metal component stops rotating, and the inner diameter visual probe is activated and moved along the axis of the metal component to perform visual inspection on the inner surface of the metal component. The specific steps of visual inspection are: Step S41: Scan the outer surface and inner surface of the metal component line by line along the axis direction using an outer diameter visual probe and an inner diameter visual probe to obtain a visual signal acquisition image; Step S42: Image processing: First, the visual signal acquisition image is grayed to obtain a grayscale image. The grayscale value of each pixel in the image for: Where: R i 、G i 、B i Respectively represent i The color values ​​of the red channel, green channel, and blue channel of each pixel; Represent the weight coefficients of the color values ​​corresponding to the red channel, green channel, and blue channel respectively; Afterwards, the grayscale image is denoised: Where: (x,y) Indicates the coordinates of the corresponding pixel point; represents the standard deviation; Then, the Sobel operator is used to perform edge detection on the grayscale image after denoising, and the area surrounded by the upper edge, lower edge, left edge and right edge is divided out to obtain the target image, and the rest of the image is removed as invalid background. Finally, set the binarization threshold T , perform binarization on the target image to obtain a binary image: like Gray(i)≥T , then the gray value of the pixel is 255, if Gray(i)< T , then the gray value of the pixel is 0; Step S43: Compare the obtained binary image with the preset standard defect binary image point by point. If the pixel matches, the pixel is marked as "1" and the coordinates of the corresponding pixel are obtained. (x i ,y i ) , otherwise it is recorded as "0"; Get the center point of all pixels marked as "1" (x 0 ,y 0 ) : Center point (x 0 ,y 0 ) is the center of the circle, r A circular frame is drawn around the pixels marked as "1" with a radius of 0.

001. If the number of pixels marked as "1" in the circular frame exceeds 2 / 3 of the area of ​​the corresponding circular frame, the area is determined to be a defect; otherwise, it is not determined to be a defect. Count the number and area of ​​all areas judged as defects and preset the defect area threshold S d Defect count threshold N d If the total area of ​​the defective regions detected is not less than the defect area threshold and / or the number of defects is not less than the defect number threshold, the corresponding metal component is determined to be unqualified, and the total defect area S and the number of defects N are recorded; Otherwise, the metal component is judged to be qualified; Step S5, workpiece judgment: first transfer the unqualified products detected by visual inspection to the unqualified area; then make a joint judgment on the qualified products detected by visual inspection, transfer the unqualified products detected by joint judgment to the unqualified area, and transfer the qualified products to the conveying mechanism for the next step.

2. A metal component surface defect joint detection method according to claim 1, characterized in that: During the eddy current detection process in step S2, the distance between the end of the outer diameter eddy current probe and the outer surface of the metal component is 1 to 5 mm, and the distance between the end of the inner diameter eddy current probe and the inner surface of the metal component is 1 to 5 mm.

3. A metal component surface defect joint detection method according to claim 2, characterized in that: During the visual inspection process of step S4, the distance between the end of the outer diameter visual probe and the corresponding outer surface of the metal component is 20 to 50 mm; the inner diameter visual probe is collinear with the central axis of the data component, and the inner diameter visual probe moves from the outside to the inside of the metal component during the inspection process.

4. The method for joint detection of surface defects of metal components according to claim 1, characterized in that: described r 0.5~5mm.

5. The method for joint detection of surface defects of metal components according to claim 1, characterized in that: The joint judgment in step S5 is specifically to obtain the joint judgment value of eddy current detection and visual detection P : Where: a represents the eddy current peak equivalent, b Indicates the visual defect area equivalent, c Indicates the equivalent number of visual defects; Preset joint judgment threshold P d If the joint judgment value is not less than the joint judgment threshold, the corresponding metal component is judged to be unqualified; otherwise, it is judged to be qualified.

Images