An automatic detection device and method for tooling planar scribing based on image recognition

Abstract

This application provides an automatic detection device and method for tooling planar engraving based on image recognition. The device includes a PH20 probe and an automatic detection component. The PH20 probe is installed on the Z-axis transmission device of a coordinate measuring machine, and the automatic detection component is connected to the PH20 probe. The automatic detection component includes a wireless transmission module, an industrial camera module, a fixed housing, a pen tip, a marker pen, a buffer spring, and a fixing screw. The wireless transmission module and the industrial camera module are pre-installed in reserved compartments inside the fixed housing. The fixed housing is fixed to the probe rod by fixing screws. The pen tip is installed in a reserved hole at the bottom of the marker pen. After the marker pen is filled with red ink, it is aligned axially with the probe rod and installed in the reserved compartment near the bottom of the middle of the fixed housing along with the buffer spring. The marker pen is then fixed with fixing screws. The side of the marker pen has grooves to ensure that the marker pen will not come out after the screws are tightened, and the buffer spring can be compressed along the Z-axis.

Description

Technical Field

[0001] This application belongs to the field of digital inspection technology of coordinate measuring machines, specifically relating to an automatic inspection device and method for tooling plane engraving based on image recognition. Background Technology

[0002] Tooling scribing consists of a series of grooves with relatively small depths and widths, mainly including part outlines, chemical milling lines, and hole center crosshairs. It is used to ensure the correctness of the product's outline or the position and shape of precision holes when using tooling to process products. At the same time, the red marks of defective points also provide workers with the correct basis for re-repairing the scribing. Therefore, the accuracy of tooling scribing is an important factor in ensuring product quality.

[0003] Faced with the increasingly severe situation of rising production volumes, traditional manual marking and inspection methods are inefficient and unable to provide quantitative judgments. Therefore, a breakthrough in precise and rapid inspection technology for tooling scribing is urgently needed. The traditional inspection method involves manually spreading red pigment powder evenly on the probe of a coordinate measuring machine (CMM). When the probe touches the theoretical position of the scribing extraction point, a red pigment powder mark is left on the tooling surface. The measuring personnel then visually determine whether the red mark is on the actual scribing line, thus qualitatively inferring the quality of the scribing. The advantage of the traditional method is its applicability to tooling scribing on complex curved surfaces, but its drawbacks are also obvious, mainly in the following three aspects:

[0004] 1. The application of red bile powder must be done entirely manually, which is time-consuming, labor-intensive, and results in uneven application. The amount of red bile powder on the probe is limited, requiring the measuring personnel to constantly observe and apply it as needed to ensure that no mark is left when a point is touched due to insufficient red bile powder. In addition, the manual application of red bile powder results in inconsistent size of each mark; marks that are too large or too small will affect the interpretation of the results. This task relies entirely on the operating experience of the measuring personnel.

[0005] 2. The qualification of tooling scribing depends entirely on the human eye's judgment of the relative positional relationship between the red mark and the actual scribing. This method is inefficient and the judgment results are unstable. Whether the tooling scribing is qualified or not depends entirely on the operator's work experience, the clarity of the red mark, the depth and thickness of the scribing, and various uncontrollable factors such as the intensity of light at the time. Summary of the Invention

[0006] Objective: To provide an automatic detection device and method for tooling planar scribing based on image recognition. The automatic detection device, containing a high-precision industrial camera and a marker pen, replaces the stylus in situ on a PH20 measuring base and fixes it to a measuring rod, ensuring the marker pen and measuring rod are coaxially aligned. A coordinate measuring machine controls the automatic detection device to perform a series of processes, including marking at pre-extracted theoretical positions and taking images at higher elevations. The images are transmitted wirelessly to a computer. A pre-set algorithm quickly analyzes the center point of the red marker pixel cluster and the edge contour of the nearby scribing line. Finally, the distance between the center point of the red marker and the edge of the scribing line is converted into the actual size using the number of pixels. This process ensures that the automatic detection device completes the scribing line detection task simultaneously while continuously operating until all pre-extracted theoretical positions are marked.

[0007] In a first aspect, this application provides an automatic detection device for tooling planar engraving based on image recognition. The device includes a PH20 probe and an automatic detection component. The PH20 probe is mounted on the Z-axis transmission device of a coordinate measuring machine, and the automatic detection component is connected to the PH20 probe.

[0008] The automatic detection component includes a wireless transmission module, an industrial camera module, a fixed housing, a pen tip, a marking pen, a buffer spring, and fixing screws.

[0009] The wireless transmission module and industrial camera module are pre-installed in reserved compartments inside the fixed housing. The fixed housing is fixed to the measuring rod with fixing screws. The pen tip is installed in the reserved hole at the bottom of the marking pen. After the marking pen is filled with red ink, it is aligned with the measuring rod axis along with the buffer spring and installed in the reserved compartment at the bottom of the middle of the fixed housing. The marking pen is then fixed with fixing screws. The marking pen has grooves on its side to ensure that the marking pen will not come out after the screws are tightened, and the buffer spring can also be compressed in the Z direction.

[0010] Preferably, the probe needs to be removed before the housing is fixed to the probe rod by fixing screws.

[0011] Preferably, the fixed housing includes an industrial camera compartment, an industrial camera lens compartment, screw fixing holes, a marker pen and buffer spring compartment, a measuring rod fixing compartment, a wireless transmission module compartment, and a measuring rod limiting hole.

[0012] Preferably, the industrial camera compartment is designed according to the size of the industrial camera module and the industrial camera module is installed and packaged before use. At the same time, it ensures that the lens of the industrial camera module is vertically downward and inside the industrial camera lens compartment. The two screw fixing holes at the lower end are used to fix the marking pen and the buffer spring, and the two screw fixing holes at the upper end are used to fix the measuring rod in the measuring rod fixing compartment.

[0013] Preferably, the marker pen and buffer spring can accommodate the marker pen and buffer spring and ensure that they can move vertically up and down inside. The marker pen and buffer spring compartment and the measuring rod fixing compartment are not connected to ensure that the position of the automatic detection device along the Z term is fixed.

[0014] Preferably, the wireless transmission module compartment is designed according to the size of the wireless transmission module and the wireless transmission module is installed and packaged before use. The measuring rod limiting hole is a hole with the same outer diameter as the measuring rod to restrict the X and Y degrees of freedom of the automatic detection device.

[0015] Secondly, this application also provides an automatic detection method for tooling planar scribing lines based on image recognition, the method comprising the following steps:

[0016] Step 1: Operate the coordinate measuring machine to return the PH20 probe to the origin position of the coordinate measuring machine;

[0017] Step 2: Use the pre-set PC-DMIS program to make the ruby ​​tip touch a standard ball with a pre-calibrated diameter to verify whether the accuracy of the coordinate measuring machine meets expectations.

[0018] Step 3: Remove the probe, pass the probe rod through the probe rod limiting hole and the probe rod fixing chamber in sequence, and tighten it with screws to ensure that the automatic detection device will not loosen. At the same time, ensure that the probe rod reaches the bottom of the probe rod fixing chamber to ensure that the Z-axis height is fixed.

[0019] Step 4: Fill the marker pen with red ink, then place the buffer spring and the marker pen holder into the marker pen and buffer spring chamber in sequence, and tighten the screws to ensure that the buffer spring and the marker pen holder do not come out completely.

[0020] Step 5: Turn on the wireless transmission module and industrial camera module, and confirm that the connection with the computer is normal;

[0021] Step 6: Using the pre-defined PC-DMIS program, the pen tip is tested on a calibration board with a scale. The image is captured by the industrial camera module and sent to the computer. Once the scale base k is confirmed to be correct and the center of the mark falls on the center line of the calibration board, the automatic detection device is considered to be in normal accuracy and usable. Here, the scale base k is the size of each pixel at a unit distance.

[0022] Step 7: Measure the height of the fixture to be measured on the measuring machine platform using a height gauge, and adjust the safety plane height h in the PC-DMIS program to ensure that the pen tip will not press down excessively and cause damage to the equipment;

[0023] Step 8 calls the pre-programmed PC-DMIS scribing measurement program for the tooling. The coordinate measuring machine will lower the pen tip to touch the surface of the tooling at each pre-extracted theoretical position, leaving a red mark, and then raise it back to the safe plane height and start the industrial camera module to take an image of the current part.

[0024] Step 9: The industrial camera module sends the image to the computer. The pre-set algorithm first extracts the pixels in the red marked area, calculates all the points of the outermost contour of the red marked area, takes any point on the outermost contour, calculates the distance to other points on the outermost contour and finds the maximum value. The midpoint of the line connecting the maximum value and that point is the center O of the circle.

[0025] Step 10: Repeat step 9 to find a center O for each point on the outermost contour. These center Os will form a smaller red area again. Similarly to step 9, find the center point at each point on the outermost contour of the red area. Repeat this process until a unique center O is found. This center O is the theoretical centerline of the engraved line at that location.

[0026] Step 11 again uses the algorithm to extract the outermost pixels on both sides of the groove. Select the left endpoint P1 on one side of the groove and calculate the straight-line distance m between this point and all points on the other side, which is m pixels apart. Calculate the straight-line distance l = m × k × h. Find the minimum value among all the straight-line distances and connect this point with P1 to obtain the midpoint Q1. Apply this step similarly to all points on this side of the groove and connect all the midpoints Q in sequence to form the actual central axis of the groove.

[0027] Step 12: Following the principle of Step 11, calculate the minimum straight-line distance l between the center O of the red-marked area and the actual central axis. min If l min If the value is greater than 0.5d, where d is the tolerance bandwidth, then the marking at the current position can be considered unqualified and out of tolerance. min -0.5d; if l min If the value is ≤0.5d, the marking at the current position can be considered acceptable.

[0028] Preferably, the method further includes:

[0029] Step 13: The PC-DMIS scribing measurement program automatically repeats steps 8 to 12 until all pre-extracted theoretical points have been measured, and the computer outputs the measurement conclusions.

[0030] This application has the following technical effects:

[0031] 1. The automatic detection device designed using this invention can replace the PH20 probe with a marking pen in situ and can automatically complete the marking. Compared with the previous manual application of red ink, this automatic detection device can ensure the uniformity of the size, color and roundness of the red mark, avoiding misjudgment due to the appearance of the red mark; in addition, the device carries a sufficient amount of red ink and can automatically complete the marking work, which can significantly improve the detection efficiency of tooling plane engraving lines.

[0032] 2. Image recognition technology enables precise and rapid detection of tooling planar scribing lines at the pixel level. Compared to the previous method of manually judging the relative position of red markers and scribing lines, image recognition technology can quickly analyze the center point of the red marker pixel cluster and the edge contour of nearby scribing lines. Finally, the distance between the center point of the red marker and the edge of the scribing line is converted into the actual size using the number of pixels. This method not only solves the problem of inaccurate measurement results caused by manual judgment but also saves a significant amount of time processing structured light measurement point cloud data.

[0033] 3. The automatic detection device designed using this invention can be quickly installed and removed from the PH20 probe holder without complicated preparation work. Simply remove the PH20 probe from the suction cup and then install the automatic detection device in its original position. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a PH20 probe provided in an embodiment of this application;

[0035] Figure 2 This is a schematic diagram of the structure of an automatic detection device for tooling plane scribing provided in an embodiment of this application;

[0036] Figure 3 This is a perspective view of a fixed housing provided in an embodiment of this application;

[0037] Figure 4 Schematic diagram of the results of planar scribing inspection;

[0038] The numbers in the diagram are explained as follows: 1. PH20 probe holder; 2. Automatic detection device; 11. Probe; 12. Suction cup; 13. Probe; 14. Ruby tip; 21. Wireless transmission module; 22. Industrial camera module; 23. Fixing housing; 24. Pen tip; 25. Marking pen; 26. Buffer spring; 27. Fixing screws (4 in total); 231. Industrial camera compartment; 232. Industrial camera lens compartment; 233. Screw fixing holes (4 in total); 234. Marking pen and buffer spring compartment; 235. Probe fixing compartment; 236. Wireless transmission module compartment; 237. Probe limiting hole. Detailed Implementation

[0039] This invention provides an automatic detection device and method for tooling planar scribing based on image recognition. The automatic detection device, containing a high-precision industrial camera and a marking pen, replaces the probe in situ on a PH20 measuring base and fixes it on a measuring rod, ensuring that the marking pen and the measuring rod are coaxially aligned. A coordinate measuring machine controls the automatic detection device to perform processes such as marking the height of the descent and taking images at pre-extracted theoretical positions. The images are transmitted to a computer via a wireless transmission module. A pre-set algorithm can quickly analyze the center point of the red marking pixel cluster and the edge contour of the nearby scribing line. Finally, the distance between the center point of the red marking and the edge of the scribing line is converted into the actual size by the number of pixels. The above process ensures that the automatic detection device can complete the scribing line detection task while running continuously until all pre-extracted theoretical positions are marked.

[0040] The PH20 probe holder includes a probe rod, a suction cup, a probe stylus, and a ruby ​​tip. The PH20 probe holder is installed on the Z-axis transmission device of a coordinate measuring machine. The probe rod is screwed and fixed to the bottom of the PH20 probe holder. The suction cup is divided into two parts: one part is fixed to the bottom of the probe rod and the other part is fixed to the top of the probe stylus. The probe stylus can be quickly installed and removed using the principle of magnetism. The ruby ​​tip is fixed to the bottom of the probe stylus for touching the workpiece.

[0041] 1. The device designed in this invention can replace the PH20 probe with a marking pen in situ and automatically complete the marking. The device is centered on the PH20 probe rod, and the tip of the marking pen is aligned with the original PH20 probe in the X and Y directions. Only simple calibration is needed to make the accuracy of the pen tip in the X and Y directions consistent with the coordinate measuring machine. A buffer spring is designed in the Z direction so that the pen tip will not be damaged when it touches the tooling surface, nor will the PH20 probe be damaged. Before use, the safety plane of the coordinate measuring machine is set, and the original scribing measurement program can be used to complete the automatic marking of the scribing.

[0042] 2. Utilizing image recognition technology, precise and rapid detection of planar scribing lines on tooling can be achieved at the pixel level. The characteristic of planar scribing lines is that the ratio between pixels and actual dimensions is only affected by the shooting distance, without interference from curved surfaces or distortion caused by illegal shooting directions. Furthermore, image size conversion technology is stable and mature. Using this stable technology, the center point of the red-marked pixel cluster and the edge contour of the nearby scribing lines can be quickly analyzed. Finally, the distance between the center point of the red mark and the edge of the scribing line is converted into the actual size using the number of pixels, enabling rapid and automatic detection of planar scribing lines on tooling. This method not only solves the problem of inaccurate measurement results caused by manual visual judgment but also saves a significant amount of time processing structured light measurement point cloud data.

[0043] 3. The device designed using this invention can be quickly installed and removed from the PH20 probe holder without cumbersome preparation. Simply remove the PH20 probe from the suction cup and then install the device in its original position. The tip of the marking pen replaces the ruby ​​end of the PH20 probe. At each theoretical position of the engraving extraction point, the probe descends along the Z-axis to a predetermined height, and the pen tip touches the surface of the tooling to complete the marking. When the probe rises back to the predetermined height along the Z-axis, the industrial camera automatically captures the current position and transmits the image back to the computer wirelessly. The software automatically determines whether the point is qualified or not.

[0044] like Figures 1-4The image-recognition-based automatic inspection device for tooling planar engraving includes a PH20 probe 1 and an automatic inspection device 2. The PH20 probe 1 includes a probe rod 11, a suction cup 12, a probe 13, and a ruby ​​tip 14. The PH20 probe 1 is mounted on the Z-axis transmission device of a coordinate measuring machine. The probe rod 11 is screwed and fixed to the bottom of the PH20 probe 1. The suction cup 12 is divided into two parts: one part is fixed to the bottom of the probe rod 11, and the other part is fixed to the top of the probe 13. The probe 13 can be quickly installed and removed using a magnet. The ruby ​​tip 14 is fixed to the bottom of the probe 13 for contacting the workpiece. The automatic inspection device 2 includes a wireless transmission module 21 and an industrial phase... The device module 22, fixed housing 23, pen tip 24, marker pen 25, buffer spring 26, and fixing screws 27 (4 in total) are pre-installed in the reserved compartment inside the fixed housing 23. The fixed housing 23 is fixed to the probe 11 by fixing screws 27 (the probe 13 needs to be removed beforehand). The pen tip 24 is installed in the reserved hole at the bottom of the marker pen 25. After the marker pen 25 is filled with red ink, it is aligned axially with the probe 11 along with the buffer spring 26 and installed in the reserved compartment near the bottom of the middle of the fixed housing 23. The marker pen 25 is then fixed with fixing screws 27. The marker pen 25 has grooves on its side to ensure accuracy. After tightening screw 27, the marker pen 25 will not come out and can also compress the buffer spring 26 in the Z direction. The fixed housing 23 includes an industrial camera compartment 231, an industrial camera lens compartment 232, screw fixing holes 233 (4 in total), a marker pen and buffer spring compartment 234, a measuring rod fixing compartment 235, a wireless transmission module compartment 236, and a measuring rod limiting hole 237. The industrial camera compartment 231 is designed according to the size of the industrial camera module 22 and is installed and packaged before use, while ensuring that the lens of the industrial camera module 22 is vertically downward and inside the industrial camera lens compartment 232. The two screw fixing holes 233 at the lower end are used to fix the marker pen 25. The upper end of the buffer spring 26 and the two screw fixing holes 233 are used to fix the fixed measuring rod 11 in the measuring rod fixing compartment 235. The marking pen and buffer spring compartment 234 can accommodate the marking pen 25 and the buffer spring 26 and ensure that they can move vertically up and down inside. The marking pen and buffer spring compartment 234 and the measuring rod fixing compartment 235 are not connected to ensure that the position of the automatic detection device 2 along the Z direction is fixed. The wireless transmission module compartment 236 is designed according to the size of the wireless transmission module 21 and the wireless transmission module 21 is installed and packaged before use. The measuring rod limiting hole 237 uses a hole with the same outer diameter as the measuring rod 11 to restrict the X and Y directions of freedom of the automatic detection device 2.

[0045] In other embodiments of this application, an automatic detection method for tooling planar scribing lines based on image recognition includes the following steps:

[0046] Step 1: Operate the coordinate measuring machine to return the PH20 probe 1 to the origin position of the coordinate measuring machine;

[0047] Step 2: Use the pre-set PC-DMIS program to make the ruby ​​tip 14 touch a standard ball with a pre-calibrated diameter to verify whether the accuracy of the coordinate measuring machine meets expectations.

[0048] Step 3: Remove the probe 13, pass the probe 11 through the probe limiting hole 237 and the probe fixing chamber 235 in sequence, and tighten it with screw 27 to ensure that the automatic detection device 2 will not loosen. At the same time, it is necessary to ensure that the probe 11 reaches the bottom of the probe fixing chamber 235 to ensure that the Z-direction height is fixed.

[0049] Step 4: Fill the marker pen 25 with red ink, and then put the buffer spring 26 and the fixed marker pen 25 into the marker pen and buffer spring chamber 234 in sequence. Tighten the screw 27 to ensure that the buffer spring 26 and the fixed marker pen 25 will not come out completely.

[0050] Step 5: Turn on the wireless transmission module 21 and the industrial camera module 22, and confirm that the connection with the computer is normal.

[0051] Step 6: Use the pre-set PC-DMIS program to test the pen tip 24 on the calibration board with the scale bar. Take an image through the industrial camera module 22 and send it to the computer. Confirm that the scale base k (the size of each pixel at a unit distance) and the center of the mark fall on the center line of the calibration board. This means that the automatic detection device 2 is considered to be in normal accuracy and usable.

[0052] Step 7: Measure the height of the fixture to be measured on the measuring machine platform using a height gauge, and adjust the safety plane height h in the PC-DMIS program to ensure that the pen tip 24 will not be pressed down excessively and cause damage to the equipment.

[0053] Step 8 calls the pre-programmed PC-DMIS scribing measurement program for the tooling. The coordinate measuring machine will lower the pen tip 24 to touch the surface of the tooling at each pre-extracted theoretical position, leaving a red mark, and then raise it back to the safe plane height and start the industrial camera module 22 to capture an image of the current part.

[0054] Step 9: The industrial camera module sends the image to the computer. The pre-set algorithm first extracts the pixels in the red marked area, calculates all the points of the outermost contour of the red marked area, takes any point on the outermost contour, calculates the distance to other points on the outermost contour and finds the maximum value. The midpoint of the line connecting the maximum value and that point is the center O of the circle.

[0055] Step 10: Repeat step 9 to find a center O for each point on the outermost contour. These center Os will form a smaller red area again. Similarly to step 9, find the center point at each point on the outermost contour of the red area. Repeat this process until a unique center O is found. This center O is the theoretical centerline of the engraved line at that location.

[0056] Step 11: Extract the outermost pixels on both sides of the groove again using the algorithm. Select the left endpoint P1 on one side of the groove and calculate the straight-line distance m (i.e., m pixels) between this point and all points on the other side. Calculate the straight-line distance l = m × k × h. Find the minimum value among all straight-line distances and connect this point with P1 to obtain the midpoint Q1. Apply this step similarly to all points on this side of the groove and connect all the midpoints Q in sequence to form the actual central axis of the groove.

[0057] Step 12: Following the principle of Step 11, calculate the minimum straight-line distance l between the center O of the red-marked area and the actual central axis. min If l min If the deviation is greater than 0.5d (where d is the tolerance bandwidth), then the marking at the current position can be considered unqualified and out of tolerance. min -0.5d; if l min If the value is ≤0.5d, the marking at the current position can be considered acceptable;

[0058] Step 13: The PC-DMIS scribing measurement program automatically repeats steps 8 to 12 until all pre-extracted theoretical points have been measured, and the computer outputs the measurement conclusions.

Claims

1. An automatic detection method for tooling planar scribing lines based on image recognition, characterized in that, The method includes the following steps: Step 1: Operate the coordinate measuring machine to return the PH20 probe to the origin position of the coordinate measuring machine; Step 2: Use the pre-set PC-DMIS program to make the ruby ​​tip touch a standard ball with a pre-calibrated diameter to verify whether the accuracy of the coordinate measuring machine meets expectations; Step 3: Remove the probe, pass the probe rod through the probe rod limiting hole and the probe rod fixing chamber in sequence, and tighten it with screws to ensure that the automatic detection device will not loosen. At the same time, ensure that the probe rod reaches the bottom of the probe rod fixing chamber to ensure that the Z-axis height is fixed. Step 4: Fill the marker pen with red ink, then place the buffer spring and the marker pen holder into the marker pen and buffer spring chamber in sequence, and tighten the screws to ensure that the buffer spring and the marker pen holder do not come out completely. Step 5: Turn on the wireless transmission module and industrial camera module, and confirm that the connection with the computer is normal; Step 6: Using the pre-set PC-DMIS program, test the pen tip on the calibration board with the scale bar. Take an image using the industrial camera module and send it to the computer. Confirm that the scale base k is correct and the center of the mark falls on the center line of the calibration board. This indicates that the automatic detection device is in good working order and can be used. Here, the scale base k is the size of each pixel at a unit distance. Step 7: Use a height gauge to measure the height of the fixture to be measured on the measuring machine platform. Adjust the safety plane height h in the PC-DMIS program to ensure that the pen tip will not press down excessively and cause damage to the equipment. Step 8: Call the pre-programmed PC-DMIS scribing measurement program for the tooling. The coordinate measuring machine will lower the pen tip to touch the surface of the tooling at each pre-extracted theoretical position, leaving a red mark, and then raise it back to the safe plane height and start the industrial camera module to take an image of the current part. Step 9: The industrial camera module sends the image to the computer. The set algorithm first extracts the pixels of the red marked area, calculates all the points of the outermost contour of the red marked area, takes any point on the outermost contour, calculates the distance to other points on the outermost contour and finds the maximum value. The midpoint of the line connecting the maximum value position and that point is the center O of the circle. Step 10: Repeat step 9 to find a center O for each point on the outermost contour. These center Os will form a smaller red area again. Similarly to step 9, find the center point at each point on the outermost contour of the red area. Repeat this process until a unique center O is found. This center O is the theoretical centerline of the engraved line at that location. Step 11: Extract the outermost pixels on both sides of the groove again using the algorithm. Select the left endpoint P1 on one side of the groove and calculate the straight-line distance m between this point and all points on the other side, which is m pixels apart. Calculate the straight-line distance l = m × k × h. Find the minimum value among all the straight-line distances and connect this point with P1 to obtain the midpoint Q1. Apply this step similarly to all points on this side of the groove and connect all the midpoints Q in sequence to form the actual central axis of the groove. Step 12: Following the principle of Step 11, calculate the minimum straight-line distance lmin between the center O of the red marked area and the actual centerline. If lmin > 0.5d, where d is the tolerance bandwidth, then the marking at the current position is considered unqualified and the deviation value is lmin - 0.5d; if lmin ≤ 0.5d, then the marking at the current position is considered qualified.

2. The method according to claim 1, characterized in that, The method further includes: Step 13: The PC-DMIS scribing measurement program automatically repeats steps 8 to 12 until all pre-extracted theoretical points have been measured, and the computer outputs the measurement conclusion.

Images