Round hole location degree measuring method

Abstract

The invention discloses a circular hole location degree measuring method, which comprises the following steps: setting a fusion calibration block, and carrying out space fusion calibration on a 3D camera above the fusion calibration block and a plurality of 2D cameras on the side surface of the fusion calibration block; uniformly calibrating an XYZ space coordinate system of the 3D camera and a plane coordinate system of the 2D camera to a calibration block coordinate system; after calibration is completed, the fusion calibration block is removed, a to-be-tested sample is placed at the position of the fusion mark block, the 3D camera above is adjusted to scan and image the reference plane, and plane point cloud data are obtained; photographing side features of the to-be-detected sample through a plurality of 2D cameras on the side to obtain feature points, and taking a circle center coordinate of the circular hole; and according to the calibration block coordinate system, calculating the distance from the point to the surface, and recording the distance as the round hole position degree.

Description

Technical Field

[0001] This invention relates to the field of optical measurement, and more specifically, to a method for measuring the position of a circular hole. Background Technology

[0002] The side button holes, speaker holes, and microphone holes on laptops or tablets require high positional accuracy. Currently, the positional accuracy of side holes is measured by taking the distance from the center or edge of the hole to the bottom or top edge of the side. This method only measures the two-dimensional position of the side hole and is not very accurate. Alternatively, a probe is used to measure the edge features and bottom surface of the hole and calculate the distance from the center point of the hole to the surface. This method is very inefficient and cannot meet the full inspection requirements of the production line.

[0003] To improve the accuracy of side hole spatial position measurement and enhance measurement efficiency to meet the full inspection requirements of the production line, a non-contact spatial position measurement method is proposed. Summary of the Invention

[0004] To address at least one of the aforementioned technical problems, this invention proposes a method for measuring the position of a circular hole.

[0005] The first aspect of this invention provides a method for measuring the position of a circular hole, comprising the following steps:

[0006] By setting up a fusion calibration block, the 3D camera above the fusion calibration block and multiple 2D cameras on the side are spatially fused and calibrated.

[0007] The XYZ spatial coordinate system of the 3D camera and the planar coordinate system of the 2D camera are calibrated onto the calibration block coordinate system; wherein, the measurement width direction of the 3D camera is the X-axis, the scanning direction is the Y-axis, and the detection depth direction is the Z-axis;

[0008] After calibration, remove the fusion calibration block, place the sample to be tested at the position of the fusion marker block, adjust the 3D camera above to scan and image the reference plane, and obtain planar point cloud data;

[0009] Multiple 2D cameras are used to take pictures of the side features of the sample under test, obtain feature points, and determine the coordinates of the center of the circular hole.

[0010] Calculate the distance from the point to the surface based on the coordinate system of the calibration block, and record it as the positional tolerance of the circular hole.

[0011] In a preferred embodiment of the present invention, the fusion calibration block is a stepped block with symmetrical ends. The top surface of the stepped block is denoted as surface A, the bottom surface of the stepped block is denoted as surface E, and the end faces of the two ends of the stepped block are denoted as surface C and surface F, respectively. The two front and rear surfaces of the stepped surface are denoted as surface B and surface D, respectively. A plurality of dots are arranged in an array on surface B, surface D, surface C and surface F.

[0012] In a preferred embodiment of the present invention, the top surface of the step block is provided with a plurality of step surfaces, which are respectively denoted as A1, A2, A3, A4 and A5, and the plurality of step surfaces are arranged at equal intervals along the vertical direction.

[0013] In a preferred embodiment of the present invention, the steps for adjusting the pose of the 3D camera are as follows:

[0014] Place the calibration block below the 3D camera, fix the calibration block in place, and adjust the working height of the 3D camera to align with and scan the two A3 step surfaces to acquire the first set of step point cloud data. Based on the 3D camera's range, ensure the 3D camera acquires at least two step surfaces.

[0015] For each step height within the measurement range, fit the point cloud to the plane, calculate the angle between the scanning plane and the XY plane of the 3D camera coordinate system, and obtain the included angle. The measurement width and scanning direction of the 3D camera are the XY plane.

[0016] Adjust the 3D camera pose according to the included angle until the included angle is less than 0.1°.

[0017] In a preferred embodiment of the present invention, the included angle is calculated as follows:

[0018] For each step height of the scan fusion calibration block, the normal vector of the fitted plane is taken. The plane angle is the angle α between the normal vector and the coordinate system Z. The formula for calculating the angle is as follows:

[0019]

[0020] The normal vector of the plane of the fusion calibration block step in the measurement; This represents the normal vector of the 3D camera in the XY plane.

[0021] In a preferred embodiment of the present invention, the spatial coordinates of the 3D camera and the Z-axis of the 3D camera motion are calibrated through step surface A, and the steps are as follows:

[0022] Adjust the Z-axis working height to Z 轴1 Scan the first height step surface A1 to obtain the first set of point clouds;

[0023] Lower the 3D camera height to Z 轴2 Scan the second height step surface A2 to obtain the second set of point clouds;

[0024] Further reduce the Z-axis height to Z 轴3 Scan the third step at the highest level, and then scan downwards in sequence until all five steps have been scanned.

[0025] The point cloud data of each step surface is fitted into a plane with plane heights Z1, Z2, Z3, Z4, and Z5. The plane heights Z1, Z2, Z3, Z4, and Z5 are the distances from each step plane fitted by the 3D camera to the XY plane of the 3D camera, which are the height values ​​measured by the 3D camera.

[0026] Z 轴2 =Z 轴1 -10mm, Z 轴3 =Z 轴2 -10mm = Z 轴1 -20mm.

[0027] In a preferred embodiment of the present invention, it is assumed that the distance between surfaces A1 and A2 is Z1, the distance between surfaces A2 and A3 is Z2, the distance between surfaces A3 and A4 is Z3, and the distance between surfaces A4 and A5 is Z4.

[0028] Formula for calculating the deviation θ between the camera's Z-axis and the calibration block's coordinate system:

[0029]

[0030] Taking the intersection of planes B, C, and E as the origin of the coordinate system, the Z-coordinate of the measured plane in the calibration block coordinate system can be calculated using the following formula:

[0031]

[0032] Among them, Z 3D It is the plane measured by the 3D camera, and the Z-axis is the height of the axis. 轴1 Z1 is the axis height for calibrating and scanning surface A1, and Z2, Z3, Z4, and Z5 are the plane heights of the 3D camera used for calibrating and scanning surfaces A1, A2, A3, A4, and A5, respectively.

[0033] In a preferred embodiment of the present invention, the coordinate system of the side 2D camera is calibrated onto the coordinate system of the calibration block B by means of the calibration block B surface. The side 2D camera corresponding to the calibration block B surface is denoted as the B surface camera. The X coordinate of the B surface camera is... B Y B The two-dimensional coordinate system is transformed into the XZ calibration block coordinate system; the specific steps are as follows:

[0034] Adjust the working distance of the 2D camera on the B-side to enable the camera to clearly image the etched dots on the B-side;

[0035] Observe that the dots are uniform at the edges and center of the image within the camera to ensure the initial position of the camera;

[0036] Collect the outline features of the dots in the image, obtain the center and outline of the dots, and calculate the diameter, spacing and position of the dots.

[0037] The distortion and normalized coordinates can be calibrated to the calibration block coordinate system using the dot calibration plate; among them, distortion includes lens distortion and structural distortion.

[0038] In a preferred embodiment of the present invention, the formula for calculating the distortion coefficient that can be calibrated for distortion is as follows:

[0039]

[0040]

[0041] as well as,

[0042]

[0043]

[0044] To fuse the coordinates of the dots on each face of the calibration block; x and y are the coordinates of the dots read by the camera on the corresponding face; k1, k2, k3, p1, and p2 are distortion correction coefficients. The standard value for the dot diameter R = 2 mm and the standard value for the dot spacing is 5 mm; d 2 =x 2 +y 2 Substituting the x, y, and d values ​​of the origin of plane B within the field of view into the formula yields the distortion coefficients k1, k2, k3, p1, and p2.

[0045] In a preferred embodiment of the present invention, the calibration algorithm is built into the software after calibration is completed.

[0046] Adjust the Z-axis height of the 3D camera until the plane to be measured is within the camera's range, and scan the coordinates of each point on plane P as (x, y, ...).

[0047]

[0048] The camera corresponding to the side feature takes a picture of the circular hole O on the side to obtain the coordinates of the center of the side feature. Taking side B as an example, the center point O

[0049] Calculate the distance from point O to plane P, which is the center position of the circular hole O on the side.

[0050] The technical solution of the present invention has the following advantages compared with the prior art:

[0051] In this application, the 3D camera is located above the fusion calibration block and has scanning and moving Y-axis and Z-axis. It scans the bottom surface to acquire 3D point cloud data, and uses the point cloud data to fit a plane as the measurement reference plane. The 2D camera takes pictures of the circular hole from the side to obtain the center point of the circular hole. The distance from the center point of the circular hole to the reference plane is calculated as the spatial position degree of the circular hole. This application uses the 2D camera to capture the side circular hole features with high accuracy, and the 3D camera takes the bottom surface point cloud data as the reference plane. The measured side hole position degree is a spatial result, which is more accurate. Attached Figure Description

[0052] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram showing the positional distribution of the 3D camera and the 2D camera in an embodiment of the present invention;

[0054] Figure 2 This is a schematic diagram of the fusion calibration block structure according to an embodiment of the present invention;

[0055] Figure 3 This is a schematic diagram of the fusion calibration block from another angle according to an embodiment of the present invention;

[0056] Figure 4 This is a schematic diagram of the included angle in an embodiment of the present invention.

[0057] In the diagram: 1. Surface A; 2. Surface B; 3. Dot; 4. Surface F; 5. Surface D; 6. Surface C; 7. Surface E; 8. Step surface A1; 9. Step surface A2; 10. Step surface A3; 11. Step surface A4; 12. Step surface A5. Detailed Implementation

[0058] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0059] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0060] Example 1

[0061] See Figures 1-3As shown, the present invention proposes a method for measuring the position of a circular hole, comprising the following steps:

[0062] By setting up a fusion calibration block, the 3D camera above the fusion calibration block and multiple 2D cameras on the side are spatially fused and calibrated.

[0063] The XYZ spatial coordinate system of the 3D camera and the planar coordinate system of the 2D camera are calibrated onto the calibration block coordinate system; wherein, the measurement width direction of the 3D camera is the X-axis, the scanning direction is the Y-axis, and the detection depth direction is the Z-axis;

[0064] After calibration, remove the fusion calibration block, place the sample to be tested at the position of the fusion marker block, adjust the 3D camera above to scan and image the reference plane, and obtain planar point cloud data;

[0065] Multiple 2D cameras are used to take pictures of the side features of the sample under test, obtain feature points, and determine the coordinates of the center of the circular hole.

[0066] Calculate the distance from the point to the surface based on the coordinate system of the calibration block, and record it as the positional tolerance of the circular hole.

[0067] According to an embodiment of the present invention, the fusion calibration block is a stepped block with symmetrical ends. The top surface of the stepped block is denoted as surface A, the bottom surface of the stepped block is denoted as surface E, and the end surfaces of the two ends of the stepped block are denoted as surface C and surface F, respectively. The two front and back surfaces of the stepped surface are denoted as surface B and surface D, respectively. A plurality of dots 3 are arranged in an array on surface B, surface D, surface C and surface F.

[0068] According to an embodiment of the present invention, the top surface of the step block is provided with a plurality of step surfaces in sequence, which are respectively designated as step surface A1 8, step surface A2 9, step surface A3 10, step surface A4 11 and step surface A5 12, and the plurality of step surfaces are arranged at equal intervals along the vertical direction.

[0069] Specifically, the XYZ coordinate system of a 3D camera includes the camera itself, the Z-axis of motion of the 3D camera, and the scanning axis of the 3D camera (defined here as the X-axis of the 3D camera);

[0070] The calibration block is designed with equidistant steps and 3-mark dots on the side.

[0071] Each step of the calibration block is 10mm high, 10mm wide, and 50mm long to ensure that enough planar data can be obtained from each step surface.

[0072] The parallelism between each step surface of the calibration block is 0.01.

[0073] The parallelism between surface A and surface E of the calibration block is 0.01.

[0074] The parallelism between surfaces B and D of the calibration block is 0.01.

[0075] The parallelism between surfaces C and F of the calibration block is 0.01.

[0076] The perpendicularity of surface A1 of the calibration block to surface B2 and surface D5 is 0.05.

[0077] The perpendicularity of surface A of the calibration block to surface C6 and surface F4 is 0.05.

[0078] The perpendicularity of surfaces B, D, C, and F of the calibration block is 0.05.

[0079] The perpendicularity of surfaces C, F, and E of the calibration block is 0.05.

[0080] The calibration block has dots 3 with a diameter of 2mm ± 0.0005mm and a spacing of 5mm ± 0.001mm engraved on surfaces B, C, D, and F.

[0081] According to an embodiment of the present invention, the steps for adjusting the pose of the 3D camera are as follows:

[0082] Place the calibration block below the 3D camera, fix the calibration block in place, and adjust the working height of the 3D camera to align with and scan the two A3 step surfaces to acquire the first set of step point cloud data. Based on the 3D camera's range, ensure the 3D camera acquires at least two step surfaces.

[0083] For each step height within the measurement range, fit the point cloud to the plane, calculate the angle between the scanning plane and the XY plane of the 3D camera coordinate system, and obtain the included angle. The measurement width and scanning direction of the 3D camera are the XY plane.

[0084] Adjust the 3D camera pose according to the included angle until the included angle is less than 0.1°.

[0085] According to embodiments of the present invention, such as Figure 4 As shown, the method for calculating the included angle is as follows:

[0086] For each step height of the scan fusion calibration block, the normal vector of the fitted plane is taken. The plane angle is the angle α between the normal vector and the coordinate system Z. The formula for calculating the angle is as follows:

[0087]

[0088] The normal vector of the plane of the fusion calibration block step in the measurement; This represents the normal vector of the 3D camera in the XY plane.

[0089] According to an embodiment of the present invention, the spatial coordinates of the 3D camera and the Z-axis of the 3D camera motion are calibrated through step surface A, and the steps are as follows:

[0090] Adjust the Z-axis working height to Z 轴1 Scan the first height step surface A1 to obtain the first set of point clouds;

[0091] Lower the 3D camera height to Z 轴2 Scan the second height step surface A2 to obtain the second set of point clouds;

[0092] Further reduce the Z-axis height to Z 轴3 Scan the third step at the highest level, and then scan downwards in sequence until all five steps have been scanned.

[0093] The point cloud data of each step surface is fitted into a plane with heights Z1, Z2, Z3, Z4, and Z5, respectively.

[0094] Z 轴2 =Z 轴1 -10mm, Z 轴3 =Z 轴2 -10mm = Z 轴1 -20mm.

[0095] According to an embodiment of the present invention, the formula for calculating the deviation θ between the camera Z-axis and the calibration block coordinate system is as follows:

[0096]

[0097] Furthermore, due to assembly errors, there will be an angle θ between the Z-axis of the motor and the Z-axis of the 3D camera coordinate system. This angle will affect the measurement results, so it is necessary to calibrate θ.

[0098] Taking the intersection of planes B, C, and E as the origin of the coordinate system, the Z-coordinate of the measured plane in the calibration block coordinate system can be obtained using the following formula:

[0099]

[0100] Among them, Z 3D It is the plane measured by the 3D camera, and the Z-axis is the height of the axis. 轴1 Z1 is the axis height for calibrating and scanning surface A1, and Z2, Z3, Z4, and Z5 are the plane heights of the 3D camera used for calibrating and scanning surfaces A1, A2, A3, A4, and A5, respectively.

[0101] Furthermore, after calibration, the Z-axis movement of the 3D camera can be included in the measurement results, thereby increasing the measurement range.

[0102] According to an embodiment of the present invention, the coordinate system of the side 2D camera is calibrated onto the coordinate system of the calibration block by means of the calibration block B surface. The side 2D camera corresponding to the calibration block B surface is denoted as the B surface camera. The X coordinate of the B surface camera is... B Y B The two-dimensional coordinate system is transformed into the XZ calibration block coordinate system; the specific steps are as follows:

[0103] Adjust the working distance of the 2D camera on the B side to make the camera clearly image the etched dot 3 on the B side;

[0104] Observe that dot 3 is uniform in both the edge and center of the image within the camera to ensure the initial position of the camera;

[0105] The contour features of circle 3 in the image are collected to obtain the center and contour, and the diameter, spacing and position of circle 3 are calculated.

[0106] The distortion and normalized coordinates can be calibrated to the calibration block coordinate system using the dot 3 calibration plate; among them, distortion includes lens distortion and structural distortion.

[0107] According to an embodiment of the present invention, the formula for calculating the distortion coefficient that can be calibrated for distortion is as follows:

[0108]

[0109]

[0110] as well as,

[0111]

[0112]

[0113] To fuse the coordinates of the dots 3 on each face of the calibration block; x and y are the coordinates of the dots 3 read by the camera on the corresponding face; k1, k2, k3, p1, and p2 are distortion correction coefficients. The standard value of the dot 3 diameter R = 2mm and the standard value of the dot 3 spacing is 5mm; d 2 =x 2 +y 2 Substituting the x, y, and d values ​​of the origin of plane B within the field of view into the formula yields the distortion coefficients k1, k2, k3, p1, and p2.

[0114] According to an embodiment of the present invention, after calibration is completed, the calibration algorithm is built into the software.

[0115] Adjust the Z-axis height of the 3D camera until the plane to be measured is within the camera's range, and scan the coordinates of each point on plane P as (x, y, ...).

[0116]

[0117] The camera corresponding to the side feature takes a picture of the circular hole O on the side to obtain the coordinates of the center of the side feature. Taking side B as an example, the center point O

[0118] Calculate the distance from point O to plane P, which is the center position of the circular hole O on the side.

[0119] After contour transformation, the coordinates of the camera on plane B in the calibration block coordinate system are:

[0120]

[0121] Similarly, the C-side camera X C →Y,Y C →Z, X=0 calibration conversion

[0122]

[0123] D-side camera X D →X, Y D →Z, Y = -50 calibration conversion

[0124]

[0125] E-side camera X E →Y,Y E →Z, X=-90 calibration conversion

[0126]

[0127] Where, x B101 y B101 These are the x and y values ​​of point 3 in row 10 and column 1 of side B as captured by the camera on side B.

[0128] x C1010 y C1010 These are the x and y values ​​of point 3 in the 10th row and 10th column of plane C as imaged by the camera on plane C;

[0129] x D1018 y D1018 These are the x and y values ​​of point 3 in row 10 and column 18 on surface D as imaged by the camera on surface D.

[0130] x E1010 y E1010 These are the x and y values ​​of point 3 in the 1st row and 10th column of plane E as imaged by the camera on plane E.

[0131] In summary, the 3D camera in this application is located above the fusion calibration block and has scanning and moving Y-axis and Z-axis; it scans the bottom surface to acquire 3D point cloud data, and uses the point cloud data to fit a plane as the measurement reference plane; the 2D camera takes pictures of the circular hole from the side to obtain the center point of the circular hole, and calculates the distance from the center point of the circular hole to the reference plane, which is the spatial position degree of the circular hole. This application uses the 2D camera to capture the side circular hole features with high accuracy, and the 3D camera takes the bottom surface point cloud data as the reference plane. The measured side hole position degree is a spatial result, which is more accurate.

[0132] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0133] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to the above embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0134] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A round hole position tolerance measurement method, characterized by, The method comprises the following steps: The 3D camera above the fusion calibration block and the multiple 2D cameras on the side are spatially fused and calibrated by setting the fusion calibration block; The XYZ spatial coordinate system of the 3D camera and the plane coordinate system of the 2D camera are calibrated to the calibration block coordinate system, wherein the measurement width direction of the 3D camera is the X axis, the scanning direction is the Y axis, and the detection depth direction is the Z axis; After the calibration is completed, the fusion calibration block is removed, the sample to be measured is placed at the position of the fusion calibration block, the upper 3D camera is adjusted to scan the reference plane to form an image, and the plane point cloud data is obtained; The side features of the sample to be measured are photographed by the multiple 2D cameras on the side, the feature points are obtained, and the circular hole center coordinates are obtained; According to the calibration block coordinate system, the distance from the point to the plane is calculated and recorded as the circular hole position degree.

2. The circular hole position tolerance measurement method according to claim 1, wherein The fusion calibration block is a symmetrical stepped block at both ends, the top surface of the stepped block is recorded as the A surface, the bottom surface of the stepped block is recorded as the E surface, and the end surfaces at both ends of the stepped block are recorded as the C surface and the F surface; the front surface and the rear surface of the stepped surface are recorded as the B surface and the D surface, respectively, and a plurality of circular points are arranged on the B surface, the D surface, the C surface and the F surface.

3. The circular hole position tolerance measurement method according to claim 2, wherein The top surface of the stepped block is sequentially provided with a plurality of stepped surfaces, and the plurality of stepped surfaces are recorded as A1, A2, A3, A4 and A5, respectively, and the plurality of stepped surfaces are arranged at equal intervals along the vertical direction.

4. The circular hole position tolerance measurement method according to claim 3, wherein The steps of adjusting the posture of the 3D camera are as follows: The calibration block is placed below the 3D camera, the calibration block is fixed and kept stationary, the working height of the 3D camera is adjusted to align with the two A3 stepped surfaces to scan, and the first group of stepped point cloud data is obtained. According to the range of the 3D camera, the 3D camera obtains at least two stepped surfaces; The point cloud of each stepped height in the measurement range is fitted to a plane, the angle of the scanning plane relative to the XY plane of the 3D camera coordinate system is calculated, and the included angle is obtained; the measurement width and the scanning direction of the 3D camera are the XY plane; The posture of the 3D camera is adjusted according to the included angle until the angle of the included angle is less than 0.1°.

5. The circular hole position tolerance measurement method according to claim 4, wherein The included angle calculation method is as follows: The normal vector of the plane obtained by fitting the points of each stepped height of the scanned fusion calibration block is taken, the plane angle is the included angle α between the normal vector and the coordinate system Z, and the included angle calculation formula is as follows: represents the normal vector of the plane of the measured fusion calibration block step; represents the normal vector of the 3D camera XY plane.

6. The circular hole position tolerance measurement method according to claim 1, wherein The spatial coordinates of the 3D camera and the 3D camera motion Z axis are calibrated through the stepped surface A, and the steps are as follows: Adjusting the Z-axis working height is Z 轴1 Scanning the first height step surface A1 to obtain a first group of point clouds; Lower 3D camera height for Z 轴2 Scan the second height step surface A2 to obtain a second group of point clouds; Lower the Z-axis height to Z 轴3 Scan the third height step, and sequentially lower the scanning until all the 5 step surfaces are scanned. The point cloud data of each stepped surface is fitted to a plane, and the plane heights are Z1, Z2, Z3, Z4 and Z5, respectively; the plane heights Z1, Z2, Z3, Z4 and Z5 are the distances from the fitted stepped planes of the 3D camera scanning to the XY plane of the 3D camera, that is, the height values measured by the 3D camera; Z 轴2 = Z 轴1 -10 mm, Z 轴3 = Z 轴2 -10 mm = Z 轴1 -20 mm.

7. The circular hole position tolerance measurement method according to claim 6, wherein The camera Z axis and the calibration block coordinate system deviation θ calculation formula: The intersection point of the B, C and E surfaces is taken as the coordinate system origin; it can be obtained that the Z coordinate of the measurement plane in the calibration block coordinate system is wherein Z 3D is the plane measured by the 3D camera, Z is the height of the axis, Z 轴1 is the height of the axis for which the plane of the scan A1 is calibrated, Z1, Z2, Z3, Z4, Z5 are the plane heights of the 3D camera for which the planes of the scans A1, A2, A3, A4, A5 are calibrated, respectively.

8. The circular hole position tolerance measurement method according to claim 6, wherein The side 2D camera coordinate system is calibrated to the calibration block coordinate system by calibrating the B face, the side 2D camera corresponding to the B face of the calibration block is recorded as the B face camera, and the X B Y B The two-dimensional coordinate system is converted into the XZ calibration block coordinate system; the specific steps are as follows: The working distance of the B surface 2D camera is adjusted to make the camera clearly image the etched circular points on the B surface; The imaging edges and centers of the circular points in the camera are observed to be uniform to ensure the initial position of the camera; The circular center and the contour are obtained by collecting the image circular point contour features, and the circular point diameter, the circular point spacing and the circular point position are calculated. The distortion and the normalized coordinates can be calibrated to the calibration block coordinate system through the circular point calibration board; wherein the distortion includes lens distortion and structural distortion.

9. The circular hole position tolerance measurement method according to claim 8, wherein The distortion coefficient calculation formula of the calibratable distortion is as follows: And, To fuse the calibration block each face of the dot coordinates; x, y for the corresponding face camera reading dot coordinates; k1, k2, k3, p1, p2 for distortion correction coefficient, known dot diameter standard value R = 2mm, dot spacing standard value is 5mm; d 2 = x 2 +y 2 , the field of view of B face origin x, y, and d; into the formula can be obtained distortion coefficient k1, k2, k3, p1, p2.

10. The round hole position tolerance measurement method of claim 6, wherein, After the calibration is completed, the calibration algorithm is embedded into the software, Adjust the height of the Z axis of the 3D camera to the plane to be measured within the range of the camera, and scan the coordinates of each point on the plane P as (x, y, ) The camera corresponding to the side feature takes a picture of the side round hole O to obtain the side feature center coordinate. Taking the B face as an example, the center point O The distance from the O point to the plane P is calculated, that is, the center position degree of the side hole O; the plane P is a set position degree measurement reference surface.

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