Defect positioning method and system based on laser and visual online detection

Abstract

The invention relates to the technical field of optical test defects, in particular to a defect positioning method and system based on laser and visual online detection. Comprising the following steps: monitoring a concave-convex defect problem on the surface of the enameled wire through laser, monitoring a color defect problem on the surface of the enameled wire through vision, calling out image data of a concave-convex defect position from real-time image data, and identifying the image data by adopting a shadow depth analysis technology; the matching difference value of the laser concave-convex data and the visual concave-convex data is calculated, when the matching difference value is larger than a difference threshold value, an error signal is output, and the concave-convex data of the concave-convex defect position is verified through the visual feedback image data again, so that mutual verification of laser monitoring and visual monitoring is facilitated, and the defect detection accuracy is improved; and when any one of laser monitoring or visual monitoring outputs abnormal data, a worker can be alerted in time, so that the monitoring effect of the enameled wire performance is prevented from being influenced when equipment is damaged.

Description

Technical Field

[0001] The present invention relates to the technical field of optical defect testing, and in particular to a defect positioning method and system based on laser and visual online detection. Background Art

[0002] During production, enameled wire may occasionally experience quality issues due to molds, paint, and foreign matter, such as air bubbles, particles, and surface impurities. These defects can significantly reduce the electrical insulation performance of the enameled wire, far below the product design requirements. Therefore, to ensure 100% product safety and reliability, online monitoring technology must be used to conduct a full inspection of the product.

[0003] In recent years, with the development of online monitoring technology, laser online monitoring technology and visual online monitoring technology have been widely used. For example, Chinese patent application number CN202410984093.X discloses a cable detection system that combines laser and vision, including a processing module, a laser generator, a cable installation rotation mechanism, a laser receiving device, and a visual detection device. The cable installation rotation mechanism is used to place the cable and drive the cable to rotate. The laser generator is located obliquely above the cable installation rotation mechanism, the visual detection device is located directly above the cable installation rotation mechanism, and the laser receiving device is located on the other side of the cable installation rotation mechanism. The purpose of the present invention is to provide a cable detection system that combines laser and vision, which uses laser to screen out suspected defect areas, and then analyzes and judges the suspected defect areas through vision, thereby greatly improving the detection efficiency of cable defects; However, these technologies still have some shortcomings. The laser monitoring system has high measurement accuracy, but is greatly affected by wire fluctuations and is prone to false alarms. It cannot distinguish the size of particles and it is difficult to verify the accuracy of particle positioning. The visual monitoring system is good at identifying color defects, but it has more false alarms for oil stains and cannot detect defects with high altitude. It is easy to miss some small particles. In view of this, we propose a system that includes laser + 2D camera + insulation detection. The defects are detected through the above-mentioned "three-in-one" equipment. When the defect is detected, a small character inkjet printer is used to mark the defect location, and then a visual system is added to determine whether the inkjet printer is marking normally, forming a closed-loop detection system. Summary of the Invention

[0004] The purpose of the present invention is to provide a defect location method and system based on laser and visual online detection to solve the problems raised in the above background technology.

[0005] To solve the above technical problems, one of the objectives of the present invention is to provide a defect location method based on laser and visual online detection, comprising the following steps: S1. Continuously scan the same position on the surface of the enameled wire using a laser and a visual monitoring device. The visual monitoring device captures the laser reflection point on the enameled wire surface to feedback the surface concave-convex defects of the enameled wire and records the laser concave-convex data. The laser concave-convex data includes the height information and the location of the concave-convex defect. When the height information of the concave-convex defect does not match the height threshold range, a concave-convex defect signal is output and an early warning is issued. S2. Use visual monitoring equipment to capture real-time image data of the enameled wire surface and use image analysis technology to identify the color data of the enameled wire surface. When the color data does not match the color threshold range, a color defect signal is output and an early warning is issued. Color defects include color difference defects and color spot defects. S3. After receiving the concave-convex defect signal, the image data of the concave-convex defect position is retrieved from the real-time image data, the shadow depth analysis technology is used to identify the image data, the visual concave-convex data in the image data is fed back, and the matching difference value between the laser concave-convex data and the visual concave-convex data is calculated. When the matching difference value is greater than the difference threshold, an error signal is output.

[0006] Preferably, the warning in S1 is electrically connected to the first indicator light, and is used to drive the first indicator light to emit a warning when sensing a concave-convex defect signal. The warning in S2 is electrically connected to the second indicator light, and is used to drive the second indicator light to emit a warning when sensing a color defect signal.

[0007] Preferably, the step of capturing the reflection point of the laser on the surface of the enameled wire and feeding back the surface concave-convex defects of the enameled wire in S1 comprises the following steps: The laser emits a beam of laser to the surface of the enameled wire. The visual monitoring device captures the reflection point of the laser on the surface of the enameled wire and obtains the distance from the laser to the visual monitoring device. , the incident angle of the laser , the angle between the laser reflection point captured by the visual monitoring equipment and the baseline , the displacement of the laser reflection point on the image of the visual monitoring device , then the height of the enameled wire surface: ; The laser and visual monitoring equipment continuously scan the same position of the enameled wire, collecting multiple height data and calculating the average value. ,like , then the normal signal is output. If , then the concave-convex defect signal is output.

[0008] Preferably, in said S1, the position information of the concave-convex defect is determined by recording the position of the laser reflection point, and when the output concave-convex defect signal is received, the inkjet printer is driven to mark the concave-convex defect position.

[0009] Preferably, the image analysis technology is used in S2 to identify the color data of the surface of the enameled wire, including: When identifying color difference defects: convert real-time image data from RGB color space to HSV color space; Determine the standard color of the enameled wire, use Euclidean distance to calculate the color difference between each pixel and the standard color, and use a numerical comparison algorithm to compare the color difference with the color difference threshold. If the color difference is less than or equal to the color difference threshold, a normal signal is output; if the color difference is greater than the color difference threshold, a color difference defect is output. When identifying color spot defects: use edge detection algorithms to segment different areas in real-time image data, extract the color features of each area, and set a color variance threshold. If the color variance of a certain area exceeds the threshold, it is judged as a color spot defect.

[0010] Preferably, the step S3 of using shadow depth analysis technology to identify image data and feeding back visual concave-convex data in the image data comprises the following steps: Detect edges in image data through edge detection algorithm, calculate gradient information in the image, detect shadow edges, and output multiple pixel points; The surface depth h2 of each pixel is estimated by the illumination model, and the expression is: in, is the brightness of a point in the image, is the ambient light intensity, is the diffuse intensity, is the angle between the light source direction and the surface normal vector; By quantifying the surface depth h2 into a specific numerical output.

[0011] Preferably, the calculation of the matching difference between the laser concave-convex data and the visual concave-convex data in S3 includes the following steps: Average height data received from laser monitoring and the surface depth h2 of visual monitoring, normalized calculation The difference between h2 and h2; Set the difference threshold. If the difference is greater than the difference threshold, an error signal is output. If the difference is less than the difference threshold, a normal signal is output. If the difference is less than the difference threshold, a normal signal is also output. The mean method is used to calculate the error. The average value of h and h2 is used as the height information of the concave-convex defect in S1.

[0012] Preferably, S3 also includes a mark verification algorithm, which is used to collect the mark features of the inkjet printer, and use image analysis technology to extract the image data features of the concave and convex defects, and match and compare the mark features with the image data features. If they match, the normal signal of the inkjet printer is output; if they do not match, the abnormal signal of the inkjet printer is output.

[0013] A second object of the present invention is to provide a defect location system based on laser and visual online detection, comprising any one of the above-mentioned defect location methods based on laser and visual online detection, including a laser monitoring module, a visual monitoring module and a data verification module; The laser monitoring module is used to monitor the surface of the enameled wire through laser, capture the reflection points of the laser on the surface of the enameled wire to feedback the surface concave-convex defects of the enameled wire, and record the laser concave-convex data. When the height information of the concave-convex defect does not match the height threshold range, it outputs a concave-convex defect signal and issues an early warning; The visual monitoring module is used to capture real-time image data of the surface of the enameled wire through a visual monitoring device, and use image analysis technology to identify the color data of the surface of the enameled wire. When the color data does not match the color threshold range, a color defect signal is output and an early warning is issued. Color defects include color difference defects and color spot defects. The data verification module is used to receive the concave-convex defect signal, retrieve the image data of the concave-convex defect position from the real-time image data, use the shadow depth analysis technology to identify the image data, feed back the visual concave-convex data in the image data, and calculate the matching difference value between the laser concave-convex data and the visual concave-convex data. When the matching difference value is greater than the difference threshold, an error signal is output.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention not only monitors the concave-convex defect problem on the surface of the enameled wire by laser, but also monitors the color defect problem on the surface of the enameled wire by visual means. At the same time, the image data of the concave-convex defect position is retrieved from the real-time image data, the shadow depth analysis technology is used to identify the image data, the visual concave-convex data in the image data is fed back, and the matching difference value between the laser concave-convex data and the visual concave-convex data is calculated. When the matching difference value is greater than the difference threshold, an error signal is output, and the concave-convex data of the concave-convex defect position is verified again by the visual feedback image data, which is conducive to mutual verification of laser monitoring and visual monitoring, improves the accuracy of defect detection, and can timely alert the staff when either the laser monitoring or the visual monitoring outputs abnormal data to avoid equipment damage affecting the monitoring effect of the enameled wire performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flowchart of the overall process of Example 1; Figure 2 This is a schematic diagram of the marking verification principle of Example 1. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] Example 1, as Figure 1-2 As shown, one of the purposes of the present invention is to provide a defect location method based on laser and visual online detection, comprising the following steps: S1. Continuously scan the same position on the surface of the enameled wire using a laser and visual monitoring equipment. The visual monitoring equipment captures the laser reflection point on the enameled wire surface to feedback the surface concave-convex defects of the enameled wire and records the laser concave-convex data. The laser concave-convex data includes the height information and the position of the concave-convex defect. When the height information of the concave-convex defect does not match the height threshold range, a concave-convex defect signal is output and an early warning is issued. This is conducive to detecting concave-convex defects on the surface of the enameled wire through laser monitoring means. When a concave-convex defect signal appears, it can remind staff to promptly discover the concave-convex defect problem. S2. Use visual monitoring equipment to capture real-time image data of the enameled wire surface and use image analysis technology to identify the color data of the enameled wire surface. When the color data does not match the color threshold range, a color defect signal is output and an early warning is issued. Color defects include color difference defects and color spot defects. This is conducive to providing visual feedback of the color data of the enameled wire surface, facilitating the timely detection of color defects and enabling staff to understand color defect issues. S3. After receiving the concave-convex defect signal, the image data of the concave-convex defect position is retrieved from the real-time image data, the shadow depth analysis technology is used to identify the image data, the visual concave-convex data in the image data is fed back, and the matching difference value between the laser concave-convex data and the visual concave-convex data is calculated. When the matching difference value is greater than the difference threshold, an error signal is output, and the concave-convex data of the concave-convex defect position is verified again through the visual feedback image data, which is conducive to mutual verification between laser monitoring and visual monitoring, and improves the accuracy of defect detection. In addition, when either laser monitoring or visual monitoring outputs abnormal data, the staff can be alerted in time to avoid equipment damage affecting the monitoring effect of the enameled wire performance.

[0018] Expand and publish a detailed work plan based on the above: Among them, in order to enable the staff to distinguish whether it is a concave-convex defect or a color defect when receiving the early warning, the early warning in the S1 is electrically connected to the first indicator light, and is used to drive the first indicator light to emit an early warning when sensing the concave-convex defect signal. The early warning in the S2 is electrically connected to the second indicator light, and is used to drive the second indicator light to emit an early warning when sensing the color defect signal. The staff can judge whether there is a concave-convex defect based on the light of the first indicator light and judge whether there is a color defect based on the light of the second indicator light, so as to facilitate and timely determine the type of defect.

[0019] Furthermore, the step S1 captures the reflection point of the laser on the surface of the enameled wire and feeds back the surface concave-convex defects of the enameled wire, including the following steps: The laser emits a beam of laser to the surface of the enameled wire. The visual monitoring device captures the reflection point of the laser on the surface of the enameled wire and obtains the distance from the laser to the visual monitoring device. , the incident angle of the laser , the angle between the laser reflection point captured by the visual monitoring equipment and the baseline , the displacement of the laser reflection point on the image of the visual monitoring device , then the height of the enameled wire surface: ; The laser and visual monitoring equipment continuously scan the same position of the enameled wire, collecting multiple height data and calculating the average value. ,like , then the normal signal is output. If , then the concave-convex defect signal is output. By calculating the average value of multiple height data at the same position, it is beneficial to improve the accuracy of the height data and further ensure the accuracy of the concave-convex defect determination.

[0020] Secondly, the position information of the concave-convex defect is determined by recording the position of the laser reflection point in S1. When the output concave-convex defect signal is received, the inkjet printer is driven to mark the concave-convex defect position, and the concave-convex defect signal is converted into a control signal that can be recognized by the inkjet printer. The position information is converted into the coordinate system of the inkjet printer. The control signal includes the movement instruction and coding instruction of the inkjet printer. The generated control signal is sent to the control system of the inkjet printer through serial communication (such as RS-232, USB) or network communication (such as TCP / IP). The inkjet printer accurately controls the movement position through the equipped stepper motor or servo motor, and moves to the specified coordinate after receiving the control signal to perform the coding operation. The inkjet printer usually uses inkjet or laser engraving technology to mark the enameled wire.

[0021] Furthermore, the image analysis technology is used in S2 to identify the color data of the surface of the enameled wire, including: When identifying color difference defects: converting real-time image data from RGB color space to HSV color space to better separate color and brightness information; Determine the standard color of the enameled wire, use Euclidean distance to calculate the color difference between each pixel and the standard color, and use a numerical comparison algorithm to compare the color difference with the color difference threshold. If the color difference is less than or equal to the color difference threshold, a normal signal is output; if the color difference is greater than the color difference threshold, a color difference defect is output, which is beneficial for detecting color difference defects on the surface of the enameled wire; When identifying color spot defects: use edge detection algorithms (such as Canny edge detection) to segment different areas in the real-time image data, extract the color features of each area, such as average color, color variance, etc., and set a color variance threshold. If the color variance of a certain area exceeds the threshold, it is judged as a color spot defect, which is conducive to the detection of color spot defects on the surface of enameled wire.

[0022] Furthermore, the shadow depth analysis technology is used in S3 to identify the image data and to feed back the visual concave-convex data in the image data, including the following steps: Detect edges in image data through edge detection algorithm, calculate gradient information in the image, detect shadow edges, and output multiple pixel points; The surface depth h2 of each pixel is estimated by the illumination model, and the expression is: in, is the brightness of a point in the image, is the ambient light intensity, is the diffuse intensity, It is the angle between the light source direction and the surface normal vector. The illumination model is used to estimate the surface depth. Commonly used illumination models include the Lambertian reflection model. ,in, is the surface normal vector, is the direction of the light source, and the surface normal vector is inferred through the lighting model to estimate the depth; By quantifying the surface depth h2 as a specific numerical output, it is beneficial to visually monitor the concave-convex depth of the enameled wire surface, accurately detect and quantify the surface concave-convex conditions, and provide strong support for the surface quality inspection of the enameled wire.

[0023] It is worth noting that the calculation of the matching difference between the laser concave-convex data and the visual concave-convex data in S3 includes the following steps: Average height data received from laser monitoring and the surface depth h2 of visual monitoring, normalized calculation The difference between h2 and h2; Set the difference threshold. If the difference is greater than the difference threshold, an error signal is output, indicating that the error between the two detection methods is large, which may be caused by the damage of a certain device. Therefore, it is helpful for the staff to find the equipment operation status in time. If the difference is equal to the difference threshold, a normal signal is output. If the difference is less than the difference threshold, a normal signal is also output, and the mean method is used for calculation. The average value of h and h2 is used as the concave-convex defect height information in S1, which is beneficial to improving the accuracy of the concave-convex defect height information and further improving the detection of concave-convex defects.

[0024] In order to ensure that the inkjet printer can accurately mark the position of the concave and convex defects, the S3 also includes a mark verification algorithm, which is used to collect the inkjet printer mark features and use image analysis technology to extract the image data features of the concave and convex defects, and match and compare the mark features with the image data features. If they match, the normal signal of the inkjet printer is output; if they do not match, the abnormal signal of the inkjet printer is output.

[0025] A second object of the present invention is to provide a defect location system based on laser and visual online detection, including any one of the above-mentioned defect location methods based on laser and visual online detection, including a laser monitoring module, a visual monitoring module and a data verification module; The laser monitoring module is used to monitor the surface of the enameled wire through laser, capture the reflection points of the laser on the surface of the enameled wire to feedback the surface concave-convex defects of the enameled wire, and record the laser concave-convex data. When the height information of the concave-convex defect does not match the height threshold range, it outputs a concave-convex defect signal and issues an early warning; The visual monitoring module is used to capture real-time image data of the surface of the enameled wire through a visual monitoring device, and use image analysis technology to identify the color data of the surface of the enameled wire. When the color data does not match the color threshold range, a color defect signal is output and an early warning is issued. Color defects include color difference defects and color spot defects. The data verification module is used to receive the concave-convex defect signal, retrieve the image data of the concave-convex defect position from the real-time image data, use the shadow depth analysis technology to identify the image data, feed back the visual concave-convex data in the image data, and calculate the matching difference value between the laser concave-convex data and the visual concave-convex data. When the matching difference value is greater than the difference threshold, an error signal is output.

[0026] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A defect location method based on laser and visual online detection, characterized in that: The steps include: S1. Continuously scan the same position on the surface of the enameled wire using a laser and a visual monitoring device. The visual monitoring device captures the laser reflection point on the enameled wire surface to feedback the surface concave-convex defects of the enameled wire and records the laser concave-convex data. The laser concave-convex data includes the height information and the location of the concave-convex defect. Multiple height data are collected to calculate the average value of the concave-convex defect height information. When the concave-convex defect height information does not match the height threshold range, a concave-convex defect signal is output and an alarm is issued. S2. Use visual monitoring equipment to capture real-time image data of the enameled wire surface and use image analysis technology to identify the color data of the enameled wire surface. When the color data does not match the color threshold range, a color defect signal is output and an early warning is issued. Color defects include color difference defects and color spot defects. S3. After receiving the concave-convex defect signal, the image data of the concave-convex defect position is retrieved from the real-time image data, the shadow depth analysis technology is used to identify the image data, the visual concave-convex data in the image data is fed back to output the surface depth of the visual monitoring, and the matching difference value between the laser concave-convex data and the visual concave-convex data is calculated. When the matching difference value is greater than the difference threshold, an error signal is output, which is helpful for the staff to timely discover the equipment operation status. If the difference value = the difference threshold, a normal signal is output. If the difference value is less than the difference threshold, a normal signal is also output, and the average value of the concave-convex defect height information and the average value of the surface depth of the visual monitoring are calculated by the mean method as the concave-convex defect height information in S1.

2. The defect location method based on laser and visual online detection according to claim 1 is characterized in that: The warning in S1 is electrically connected to the first indicator light, and is used to drive the first indicator light to emit a warning when sensing a concave-convex defect signal. The warning in S2 is electrically connected to the second indicator light, and is used to drive the second indicator light to emit a warning when sensing a color defect signal.

3. The defect location method based on laser and visual online detection according to claim 2, characterized in that: The step S1 captures the reflection point of the laser on the surface of the enameled wire and feeds back the surface concave-convex defects of the enameled wire, including the following steps: The laser emits a beam of laser to the surface of the enameled wire. The visual monitoring device captures the reflection point of the laser on the surface of the enameled wire and obtains the distance from the laser to the visual monitoring device. , the incident angle of the laser , the angle between the laser reflection point captured by the visual monitoring equipment and the baseline , the displacement of the laser reflection point on the image of the visual monitoring device , then the height of the enameled wire surface: ； The laser and visual monitoring equipment continuously scan the same position of the enameled wire, collecting multiple height data and calculating the average value. ,like , then the normal signal is output. If , then the concave-convex defect signal is output.

4. The defect location method based on laser and visual online detection according to claim 3 is characterized in that: In the above S1, the position information of the concave-convex defect is determined by recording the position of the laser reflection point, and when the output concave-convex defect signal is received, the inkjet printer is driven to mark the concave-convex defect position.

5. The defect location method based on laser and visual online detection according to claim 4 is characterized in that: The image analysis technology used in S2 to identify the color data of the enameled wire surface includes: When identifying color difference defects: convert real-time image data from RGB color space to HSV color space; Determine the standard color of the enameled wire, use Euclidean distance to calculate the color difference between each pixel and the standard color, and use a numerical comparison algorithm to compare the color difference with the color difference threshold. If the color difference is less than or equal to the color difference threshold, a normal signal is output; if the color difference is greater than the color difference threshold, a color difference defect is output. When identifying color spot defects: use edge detection algorithms to segment different areas in real-time image data, extract the color features of each area, and set a color variance threshold. If the color variance of a certain area exceeds the threshold, it is judged as a color spot defect.

6. The defect location method based on laser and visual online detection according to claim 5, characterized in that: The step S3 uses shadow depth analysis technology to identify image data and feeds back visual concave-convex data in the image data, including the following steps: Detect edges in image data through edge detection algorithm, calculate gradient information in the image, detect shadow edges, and output multiple pixel points; The surface depth h2 of each pixel is estimated by the illumination model, and the expression is: in, is the brightness of a point in the image, is the ambient light intensity, is the diffuse intensity, is the angle between the light source direction and the surface normal vector; By quantifying the surface depth h2 into a specific numerical output.

7. The defect location method based on laser and visual online detection according to claim 6, characterized in that: Calculating the matching difference between the laser concave-convex data and the visual concave-convex data in S3 includes the following steps: Average height data received from laser monitoring and the surface depth h2 of visual monitoring, normalized calculation The difference between h2 and h2; Set the difference threshold. If the difference is greater than the difference threshold, an error signal is output. If the difference is less than the difference threshold, a normal signal is output. If the difference is less than the difference threshold, a normal signal is also output. The mean method is used to calculate the error. The average value of h and h2 is used as the height information of the concave-convex defect in S1.

8. The defect location method based on laser and visual online detection according to claim 7, characterized in that: The S3 also includes a mark verification algorithm, which is used to collect the mark features of the inkjet printer and use image analysis technology to extract the image data features of the concave and convex defects, and match and compare the mark features with the image data features. If they match, the normal signal of the inkjet printer is output; if they do not match, the abnormal signal of the inkjet printer is output.

9. A defect location system based on laser and visual online detection, comprising the defect location method based on laser and visual online detection according to any one of claims 1 to 8, characterized in that: Including laser monitoring module, visual monitoring module and data verification module; The laser monitoring module is used to monitor the surface of the enameled wire through laser, capture the reflection points of the laser on the surface of the enameled wire to feedback the surface concave-convex defects of the enameled wire, and record the laser concave-convex data. When the height information of the concave-convex defect does not match the height threshold range, it outputs a concave-convex defect signal and issues an early warning; The visual monitoring module is used to capture real-time image data of the surface of the enameled wire through a visual monitoring device, and use image analysis technology to identify the color data of the surface of the enameled wire. When the color data does not match the color threshold range, a color defect signal is output and an early warning is issued. Color defects include color difference defects and color spot defects. The data verification module is used to receive the concave-convex defect signal, retrieve the image data of the concave-convex defect position from the real-time image data, use the shadow depth analysis technology to identify the image data, feed back the visual concave-convex data in the image data, and calculate the matching difference value between the laser concave-convex data and the visual concave-convex data. When the matching difference value is greater than the difference threshold, an error signal is output.

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