Optical three-dimensional scanning measurement device and method for sorting reference circles

Abstract

The application discloses an optical three-dimensional scanning measurement device and a mark circle sorting method, and relates to the three-dimensional scanning field, and comprises the following steps: S1, acquiring a calibration image; S2, image preprocessing; S3, mark circle extraction; S4, mark circle subpixel contour extraction; S5, mark circle sorting; and S6, camera calibration. The mark circle sorting method provided by the application can realize accurate sorting of mark circles without human intervention, and improves the stability of a camera calibration algorithm based on a circular calibration board and the precision of three-dimensional reconstruction.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of three-dimensional scanning, in particular to an optical three-dimensional scanning measurement device and a method for sorting marker circles. BACKGROUND

[0002] It is known that in optical three-dimensional scanning measurement technology, fringe projection profilometry (FPP) is widely used in industrial detection, biological medicine, automobile manufacturing and other fields due to its high measurement accuracy, fast speed and non-contact characteristics. The principle of fringe projection profilometry is to project a set of coded fringe grating pictures onto the measured object through a projector, the projected fringe pictures are deformed on the surface of the object, then a camera synchronously captures the fringe grating pattern projected on the object, and finally the height information of the object can be obtained by decoding the pictures. Before three-dimensional reconstruction of the object, the entire grating projection measurement system needs to be calibrated, which includes camera calibration and projector calibration. The calibration results of the camera and the projector have an important influence on the accuracy of the entire three-dimensional reconstruction system, so it is crucial to ensure the stability and high precision of camera calibration.

[0003] For example, the patent document with the authorized announcement number CN109285194B and the authorized date of 2021-06-29, named "Camera calibration board and camera calibration data acquisition method", includes a camera calibration board, and the camera calibration board is a plane calibration board. A plurality of feature circles are arranged on the camera calibration board, and all the feature circles are arranged in an array. Three feature circles in the feature circles are defined as specific feature circles, and all the specific feature circles are not on the same straight line. The camera calibration board has specific feature circles, which can be used to position the world coordinates of other feature circles.

[0004] The traditional camera calibration method needs to manually and repeatedly adjust the position of the calibration board to obtain calibration board pictures at different positions. This method can easily affect the overall camera calibration accuracy due to the incorrect sorting of marker circles. SUMMARY

[0005] The purpose of the present application is to provide an optical three-dimensional scanning measurement device and a method for sorting marker circles to solve the above problems in the prior art.

[0006] In order to achieve the above purpose, the present application provides the following technical solutions:

[0007] A method for sorting marker circles, comprising the following steps:

[0008] S1: obtaining a calibration image;

[0009] S2: image preprocessing;

[0010] S3: marker circle extraction;

[0011] S4: logo circle sub-pixel contour extraction;

[0012] S5: logo circle sorting;

[0013] S6: camera calibration.

[0014] The logo circle sorting method, in step S1, places the circular calibration board in the camera shooting area, and adjusts the position of the circular calibration board to obtain pictures taken by the camera at various positions.

[0015] The logo circle sorting method, in step S2, first filters the pictures taken by the camera, then binarizes the image, and finally extracts all contours in the image based on the binarized image.

[0016] The logo circle sorting method, in step S3, screens out all logo circle contours.

[0017] The logo circle sorting method, in step S4, calculates the sub-pixel level contour according to the obtained logo circle contour, and fits the center and radius based on the sub-pixel level contour.

[0018] The logo circle sorting method, in step S5, sorts all logo circles to unify the order of the logo circles.

[0019] The logo circle sorting method, in step S6, establishes the three-dimensional coordinates of the logo circle centers based on the actual physical size of the circular calibration board, and then calibrates the camera in combination with the fitted logo circle center coordinates.

[0020] The logo circle sorting method, the number of rows of the circular calibration board is 9, the number of columns is 11, the center distance is 15mm, and the precision is 0.01mm.

[0021] An optical three-dimensional scanning measurement device for realizing the calibration process of a three-dimensional scanner containing a camera inside by the movement of the camera, comprising a base and a disc rotatingly arranged inside the base, the disc being provided with a three-dimensional scanner, a plurality of circular calibration boards being arranged on the base, and the plurality of circular calibration boards being located on the rotating stroke of the three-dimensional scanner; a forced centering mechanism is arranged between the three-dimensional scanner and the circular calibration board to make the three-dimensional scanner and the circular calibration board face each other; and a power assembly for driving the disc to rotate is further included.

[0022] The forced centering mechanism comprises a blocking component for shielding the circular calibration plate and a driving member for driving the blocking component to move, and the blocking component unblocks the circular calibration plate when the three-dimensional scanner is directly opposite the target circular calibration plate.

[0023] In the technical scheme, the sign circle sorting method provided by the application can realize accurate sorting of sign circles without human intervention, and improves the stability of a camera calibration algorithm based on a circular calibration plate and the accuracy of three-dimensional reconstruction. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art based on these drawings.

[0025] Figure 1 The flow chart of the sign circle sorting method provided by the embodiment of the present application is shown in the figure.

[0026] Figure 2 The front structure schematic diagram of the circular calibration plate provided by the embodiment of the present application is shown in the figure.

[0027] Figure 3a The calibration diagram provided by the embodiment of the present application is shown in the figure.

[0028] Figure 3b The binarization result diagram of the calibration diagram provided by the embodiment of the present application is shown in the figure.

[0029] Figure 3c The contour extraction diagram of the calibration diagram provided by the embodiment of the present application is shown in the figure.

[0030] Figure 3d The contour screening result diagram provided by the embodiment of the present application is shown in the figure.

[0031] Figure 4 The overall structure schematic diagram of the three-dimensional scanning device provided by another embodiment of the present application is shown in the figure.

[0032] Figure 5 The overall structure schematic diagram of the three-dimensional scanning device provided by another embodiment of the present application is shown in the figure.

[0033] Figure 6 The top view structure schematic diagram of the three-dimensional scanning device provided by another embodiment of the present application is shown in the figure.

[0034] Figure 7 The overall structure schematic diagram of the three-dimensional scanning device provided by another embodiment of the present application is shown in the figure. Figure 6 The partial sectional view at a-a in the figure.

[0035] Figure 8 This is a schematic diagram of the connection structure between the slider and the arc-shaped groove provided in another embodiment of the present invention;

[0036] Figure 9 This is a schematic diagram of the overall structure of the centering block provided in another embodiment of the present invention;

[0037] Figure 10 for Figure 4 Enlarged schematic diagram of a local structure at point A;

[0038] Figure 11 for Figure 7 Enlarged schematic diagram of the local structure at point B;

[0039] Figure 12 for Figure 7 Enlarged schematic diagram of the local structure at point C;

[0040] Figure 13 for Figure 7 Enlarged schematic diagram of the local structure at point D;

[0041] Figure 14 for Figure 8 Enlarged schematic diagram of the local structure at point E;

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. 3D scanner; 2. Circular calibration plate; 3. Disc; 4. Base; 401. Circular ring segment; 5. Baffle; 6. Torsion spring; 7. Locking block; 8. Rotating shaft; 9. First spring; 10. Fixed seat; 11. Transmission rod; 12. Unlocking block; 13. Centering block; 1301. Groove; 1302. Inclined surface; 1303. Through groove; 14. Second spring; 15. Gear; 16. Toothed plate; 17. Sliding seat; 18. Arc groove ; 19. Slider; 20. Abutment block; 21. Clearance groove; 22. Transmission rope; 23. Third spring; 24. Movable groove; 25. Fourth spring; 26. Limiting part; 27. Fixing groove; 28. Limiting block; 29. ​​Fifth spring; 30. Transmission frame; 31. First abutment part; 32. Second abutment part; 33. Slide plate; 34. Clearance hole; 35. Third abutment part; 36. Abutment plate; 37. Slide groove; 38. Sixth spring. Detailed Implementation

[0044] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] In the description of this invention, it should be understood that the 3D scanner 1 mentioned below specifically refers to its internal camera. Figure 7 The orientation of the 3D scanner 1 relative to the fixed base 10 is considered upward, and vice versa. Figure 7The orientation of the circular calibration board 2 relative to the three-dimensional scanner 1 is right, and vice versa is left. The orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like are based on the orientations or positional relationships shown in the drawings, which are merely for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0046] With reference to Figures 1-14 The circular calibration board sorting method provided by the embodiment of the present application comprises the following steps:

[0047] S1: Obtain a calibration image;

[0048] S2: Image preprocessing;

[0049] S3: Calibration circle extraction;

[0050] S4: Sub-pixel contour extraction of the calibration circle;

[0051] S5: Calibration circle sorting;

[0052] S6: Camera calibration.

[0053] Specifically, the camera is a core component in the three-dimensional scanner 1. In order to obtain better three-dimensional scanning results, the camera in the three-dimensional scanner 1 (hereinafter referred to as the three-dimensional scanner 1, which specifically refers to the camera inside the three-dimensional scanner 1) needs to be calibrated before the three-dimensional scanner 1 is used. During calibration, the calibration board is placed in the shooting area of the camera, the position and angle of the calibration board are adjusted multiple times, the calibration board under multiple positions is shot by the camera, and then integrated to obtain the focal length, principal point coordinates, and distortion parameters of the camera and other information. This is not described in detail in the prior art. One of the core innovations of the embodiment of the present application is that during camera calibration, the following steps are taken:

[0054] S1: Place the circular calibration board 2 in the shooting area of the camera, and adjust the position of the circular calibration board 2 to obtain pictures of the circular calibration board 2 shot by the camera under various positions;

[0055] S2: In order to better retain the contour features of the calibration circle, the obtained pictures need to be preprocessed, which includes: first, filtering the pictures shot by the camera, second, binarizing the image, and finally, based on the binarized image, extracting all contours in the image. Specifically, the preprocessing process is as follows: (1) filtering the pictures shot by the camera to remove noise and improve the quality of the pictures; (2) binarizing the filtered image to obtain a binary image; and (3) based on the binary image, extracting all contours in the image. Figure 3a(1) the calibration picture in the image is subjected to a bilateral filtering operation to filter out as many noise points in the picture as possible while retaining the edges of the marker circle; Figure 3b (2) the binary threshold of the picture is calculated by the Otsu method (an image is divided into two classes by a threshold, one of which is the pixels in the image whose grayscale is less than the threshold, and the other of which is the pixels in the image whose grayscale is greater than or equal to the threshold, and the greater the variance of the grayscale of the pixels in the two classes, the better the threshold obtained); then the filtered picture is binarized based on the threshold, and the binarization result is as shown in Figure 3c (3) based on the binarized image, the pixel-level contour features in the image are extracted by the findContours function in Opencv, and the extracted contour is as shown in Figure 3d (4) based on all the extracted image contours, the perimeter, area and circularity of the contour are calculated, and then a threshold is set to screen all the contours to screen out the contours belonging to the marker circle, and the screening result is as shown in (5) based on the screened marker circle contour, the sub-pixel level contour of the marker circle is extracted using the Zernike moment method to improve the accuracy of subsequent center fitting;

[0056] S3: The extracted contour may contain contours that do not belong to the marker circle, so before fitting the center and radius of the marker circle, all the contours of the marker circle need to be screened out;

[0057] S4: The extracted marker circle contour is pixel-level, in order to further improve the accuracy of camera calibration, the sub-pixel level contour of the marker circle is calculated based on the extracted marker circle contour, and then the center and radius are fitted based on the sub-pixel level contour;

[0058] S5: Since the extracted marker circle contour is disordered, its order is different at different calibration positions, so before camera calibration, all the marker circles are sorted to unify the order of the marker circles, and specifically, the sorting process is as follows: first, in order to facilitate the understanding of the entire marker circle sorting process, it is assumed that the front view of the extracted marker circle is as shown in Figure 2As shown in the figure, there are five large circles in the calibration board, which can be used to determine the orientation of the entire calibration board, that is, as long as the positions of the five large circles are known, the positions of other marked circles in the current position can be determined, so before sorting, the large circles on the calibration board need to be screened out, and all circles are sorted according to the radius from large to small, and the five circles with the largest radius are extracted, that is, the large circles are obtained, and the two large circles closest to the distance are recorded as R1 and R2, and the two large circles farthest from the distance are recorded as R3 and R4, and the other large circle is recorded as R5; second, in order to obtain all the marked circles located on the line of the large circles R1 and R2, first calculate the equation of the line L1 according to the centers of the large circles R1 and R2, then calculate the distance from the center of all circles to the line, and sort the distance from small to large, and extract the 11 circles closest to the distance, that is, all the circles on L1 are obtained, in order to sort all the circles on L1, it is necessary to determine the circle R6 at the head end on L1, from Figure 2 It can be concluded that R6 is farthest from R2, by judging the distance of all circles on L1 from R2, the largest distance is the head end circle R6, and finally by calculating the distance of all circles on L1 from R6 and sorting, the order of all circles on L1 can be determined, wherein the determination method of R2 is to calculate the center point R of R3 and R4 first, then calculate the equation of the line L according to the centers of R and R5, and finally determine the position of R2 by judging the distance of R1 and R2 from the line L; third, in order to obtain all the marked circles located on the line of the large circles R3 and R4, first calculate the equation of the line L2 according to the centers of the large circles R3 and R4, then the distance of the center of all circles from the line is judged, and all the circles on the line L2 are screened out, in order to realize the sorting of all the circles on the line L2, the head end circle R7 on L2 needs to be calculated, and the calculation method is different from L1, R7 is obtained by judging the distance of all circles on L2 from R6, from Figure 2As can be seen, the smallest distance is the first end circle R7 on L2, after R7 is obtained, by judging the distance of all circles on L2 to R7, all circles on L2 can be sorted; fourth, after all circles on L1 and L2 are sorted, all circles on the calibration plate can be sorted based on the two columns of sorted circles, first, the equation of straight line L3 is calculated according to the centers of R6 and R7, the distance of the center of all circles to the straight line is calculated, and all circles on the straight line L3 are obtained, then the distance of all circles on the straight line L3 to the straight line L1 is calculated, the farthest distance is the first end circle R8 on L3, and the sorting of all circles on the straight line L3 is completed by judging the distance of all circles on the straight line L3 to R8; finally, when all circles on the straight line L3 are sorted, the equation of the straight line Li is calculated according to the arrangement order of the circles on the straight lines L1 and L2, and the equation of the straight line Li is calculated according to the center of the circle on the straight line, all circles on the straight line Li are obtained, and the first end circle on Li is solved by the same method, and the sorting of all circles on the circular calibration plate 2 is completed by sorting all circles on Li according to the first end circle.

[0059] S6: based on the actual physical size of the circular calibration plate 2, the three-dimensional coordinates of the center of the mark circle are established, and then combined with the fitted center coordinates of the mark circle and the calibrateCamera function of Opencv, the camera calibration is completed, and the benefits brought by this are that the accurate sorting of the mark circle can be realized without human intervention, and the stability of the camera calibration algorithm based on the circular calibration plate 2 and the accuracy of three-dimensional reconstruction are improved.

[0060] Preferably, the number of rows of the circular calibration plate 2 is 9, the number of columns is 11, the center distance is 15mm, and the accuracy is 0.01mm.

[0061] In the process of camera calibration, the position of the circular calibration plate 2 needs to be adjusted manually and repeatedly, and then photographed by the camera in the three-dimensional scanner 1 to obtain the pictures of the circular calibration plate 2 at each position. Obviously, the manual adjustment multiple times reduces the accuracy and efficiency of camera calibration. As another embodiment of the present application, an optical three-dimensional scanning measurement device is used to realize the calibration process of the three-dimensional scanner 1 containing a camera inside by the movement of the camera, which comprises a base 4 and a disc 3 rotatably arranged on the base 4, the disc 3 is provided with a three-dimensional scanner 1, and the base 4 is provided with a plurality of circular calibration plates 2, and the plurality of circular calibration plates 2 are located in the shooting area in the rotation stroke of the three-dimensional scanner 1; a forced centering mechanism is arranged between the three-dimensional scanner 1 and the circular calibration plate 2 for making the three-dimensional scanner 1 and the circular calibration plate 2 face each other; and a power assembly for driving the disc 3 to rotate is further included.

[0062] Specifically, the existing camera calibration method is: during calibration, the calibration board is placed in the shooting area of the camera, and the position and angle of the calibration board need to be adjusted manually multiple times. The calibration board in multiple positions is shot by the camera, and then integrated to obtain the focal length, principal point coordinates and distortion parameters and other information of the camera. One of the core innovations of another embodiment of the present application is to provide a base 4 and a disc 3 rotatingly arranged inside the base 4. The base 4 is cylindrical, and the disc 3 is rotatingly arranged inside the base 4 and close to the top end of the base 4. The three-dimensional scanner 1 is arranged on the upper surface of the disc 3. A plurality of circular calibration boards 2 are arranged on the base 4 in a manner of vertical flipping, horizontal rotation, and close to or away from the three-dimensional scanner 1, and the plurality of circular calibration boards 2 are all located in the shooting area in the rotation stroke of the three-dimensional scanner 1. The forced centering mechanism is a cooperation structure of a photoelectric sensor and an alarm, and the power assembly is a structure for providing rotating force for a driving motor and the like. The effect of such arrangement is that the power assembly controls the rotation of the disc 3, thereby driving the three-dimensional scanner 1 above the disc 3 to rotate synchronously, so that the shooting area (lens) of the three-dimensional scanner 1 passes through each circular calibration board 2 and shoots it, to realize the automatic shooting process. When the three-dimensional scanner 1 rotates to the opposite side of the circular calibration board 2 each time, it stops to shoot. When it stops, the photoelectric sensor can detect whether the three-dimensional scanner 1 is aligned with the circular calibration board 2 (the specific alignment process is as follows: a light source emitting a linear light beam is arranged on the circular calibration board 2. When the three-dimensional scanner 1 stops, the photoelectric sensor can sense whether the linear light beam is irradiated on the sensing part on its surface. When the photoelectric sensor senses that the linear light beam is irradiated on the sensing part, it indicates that the three-dimensional scanner 1 is aligned with the circular calibration board 2. When the photoelectric sensor does not sense that the linear light beam is irradiated on the sensing part, it indicates that the three-dimensional scanner 1 is not aligned with the circular calibration board 2). When the photoelectric sensor detects that the three-dimensional scanner 1 is directly opposite the target circular calibration board 2 (i.e. the circular calibration board 2 that the camera is about to shoot), the three-dimensional scanner 1 can normally shoot. When the photoelectric sensor detects that the three-dimensional scanner 1 is not directly opposite the target circular calibration board 2, it controls the alarm to issue an alarm, so as to remind that the three-dimensional scanner 1 fails during calibration and needs to be re-adjusted, thereby ensuring that the pictures shot by the camera are all completed under the condition that the circular calibration board 2 is directly opposite, to improve the accuracy of camera calibration.

[0063] As another embodiment of the present application, the forced centering mechanism further comprises a blocking assembly for shielding the circular calibration plate 2 and a driving member for driving the blocking assembly to move, when the three-dimensional scanner 1 is directly opposite the target circular calibration plate 2, the blocking assembly unblocks the circular calibration plate 2. Specifically, the blocking assembly is a sliding plate or the like structure, which is slidingly arranged on the calibration surface of each circular calibration plate 2 and is used for shielding the calibration surface of the circular calibration plate 2. The driving member is a reciprocating driving mechanism such as an electric push rod. The arrangement has the following effects: when the three-dimensional scanner 1 is directly opposite the target circular calibration plate 2, the driving member is started, which controls the blocking assembly to slide, so that the blocking assembly is away from the circular calibration plate 2, and the calibration surface of the circular calibration plate 2 is exposed, so that normal calibration can be realized. When the three-dimensional scanner 1 is not directly opposite the target circular calibration plate 2, the driving member cannot be started, that is, the blocking assembly cannot move at this time, so that the circular calibration plate 2 cannot be exposed, and normal calibration cannot be continued. Thus, normal calibration can be realized only when the three-dimensional scanner 1 is directly opposite the circular calibration plate 2, and the circular calibration plate 2 can be protected when it is not in use.

[0064] Preferably, the blocking assembly comprises a baffle 5 which is rotationally arranged on the circular calibration plate 2, the baffle 5 has a first position for shielding the circular calibration plate 2 and a second position for opening the circular calibration plate 2, and a torsion spring 6 is arranged between the baffle 5 and the circular calibration plate 2, the base 4 is elastically provided with a locking block 7, when the baffle 5 is in the first position, the baffle 5 is attached to the circular calibration plate 2, when the baffle 5 is in the second position, the locking block 7 is located on the rotation stroke of the baffle 5, specifically, the size of the baffle 5 is matched with the size of the circular calibration plate 2, that is, the baffle 5 can completely shield the calibration surface of the circular calibration plate 2, and a rotating shaft 8 is arranged at the top end of the baffle 5, for the convenience of description, for a single circular calibration plate 2, the top end of the circular calibration plate 2 is symmetrically provided with two extensions, the two ends of the rotating shaft 8 are rotationally connected with the two extensions respectively, the torsion spring 6 is sleeved on the rotating shaft 8, and the two ends are fixedly connected with the baffle 5 and the extension respectively, the elastic force of the torsion spring 6 makes the baffle 5 have a tendency to switch from the first position to the second position, the upper surface of the base 4 has a circular ring segment 401 protruding from the convex disc 3, the locking block 7 is L-shaped, and the vertical sliding of the locking block 7 is arranged on the circular ring segment 401, the top end of the vertical section of the locking block 7 is provided with a wedge surface, and the wedge surface is located on the movement stroke of the baffle 5, and the end of the horizontal section of the locking block 7 extends to the inside of the circular ring segment 401, the elastic arrangement here means that the first spring 9 is arranged between the horizontal section and the upper surface of the base 4, the setting of this has the effect that when the baffle 5 is in the first position, that is, at this time, the baffle 5 is in a vertical state, at this time, the baffle 5 is attached to the calibration surface of the circular calibration plate 2 (in the case that the circular calibration plate 2 is in a vertical state, if the circular calibration plate 2 is slightly inclined, the corresponding baffle 5 is also slightly inclined), at this time, the vertical surface of the vertical section of the locking block 7 is in abutment with the baffle 5, so that the baffle 5 cannot be rotated, thereby stably fixing the baffle 5 in the first position to achieve shielding, when the photoelectric sensor detects that the three-dimensional scanner 1 is directly opposite the target circular calibration plate 2, at this time, it is necessary to switch the baffle 5 from the first position to the second position, the locking block 7 is provided with a vertical downward force, so that the vertical section of the locking block 7 is away from the baffle 5, thereby releasing the locking effect of the locking block 7 on the baffle 5, under the elastic force of the torsion spring 6, the baffle 5 is switched from the first position to the second position, thereby opening the target circular calibration plate 2 to achieve normal shooting.

[0065] As another embodiment of the present application, the three-dimensional scanner 1 is not directly arranged on the disc 3, and a fixing seat 10 is arranged on the disc 3, specifically, the fixing seat 10 is located above the disc 3, and the three-dimensional scanner 1 is arranged at the top end of the fixing seat 10, thereby achieving the effect of increasing the vertical height to adjust the vertical height of the three-dimensional scanner 1.

[0066] Preferably, the driving member comprises a transmission rod 11 fixedly connected to the fixed seat 10, and an unlocking block 12 elastically arranged on the transmission rod 11, and a plurality of centering blocks 13 are arranged on the base 4, and the plurality of centering blocks 13 are arranged in one-to-one correspondence with the plurality of circular calibration plates 2, and a groove 1301 adapted to the unlocking block 12 is formed in the centering block 13, and the locking block 7 is located in the groove 1301, and an inclined surface 1302 is arranged on the centering block 13, and the inclined surface 1302 is located on the movement stroke of the unlocking block 12, specifically, the transmission rod 11 is horizontally arranged, is fixedly connected to the fixed seat 10, and is located on the same side as the shooting area of the three-dimensional scanner 1, the unlocking block 12 is also L-shaped, and the vertical side of the unlocking block 12 is slidingly arranged at the end of the transmission rod 11, and the central axes of the transmission rod 11, the horizontal side of the unlocking block 12 and the shooting area of the three-dimensional scanner 1 are located on the same vertical plane, and a second spring 14 is arranged between the upper surface of the horizontal side of the unlocking block 12 and the lower surface of the transmission rod 11, and the elastic force of the second spring 14 is greater than that of the first spring 9, the centering block 13 is overall in the shape of a right-angled trapezoid, the groove 1301 is formed in the upper surface thereof, and the position of the groove 1301 and the center line of the circular calibration plate 2 are located on the same vertical plane, that is, when the unlocking block 12 enters the groove 1301, the three-dimensional scanner 1 and the target circular calibration plate 2 are in the state of facing each other, and the vertical height of the transmission rod 11 is higher than that of the upper surface of the centering block 13, and when the second spring 14 is in a natural state, the horizontal side of the unlocking block 12 and the inclined surface 1302 are located at the same vertical height, and the arrangement is for, when the disc 3 rotates, the fixed seat 10, the three-dimensional scanner 1 and the transmission rod 11 above the disc 3 are synchronously rotated around the central axis of the disc 3, in the process of rotating the transmission rod 11, the horizontal side of the unlocking block 12 and the inclined surface 1302 are abutted, under the abutting action, the unlocking block 12 is upwardly slid and the second spring 14 is compressed, the transmission rod 11 is controlled to continue rotating, so that the horizontal side of the unlocking block 12 moves above the centering block 13 and then continues to move, when the power assembly controls the transmission rod 11 to stop, the following two situations occur:Because the elastic force of the second spring 14 is greater than that of the first spring 9, the locking block 7 is moved downward synchronously, and when the vertical section of the locking block 7 is away from the baffle 5, the elastic force of the torsion spring 6 is released, and the baffle 5 is switched from the first position to the second position passively, and normal shooting can be performed.

[0067] The base 4 is provided with a switching assembly for switching the baffle 5 from the second position to the first position, the switching assembly comprises intermeshing gear 15 and toothed plate 16, the gear 15 is fixedly connected with the baffle 5, the circular calibration plate 2 is fixedly connected with sliding seat 17, the toothed plate 16 is in sliding connection with the sliding seat 17, the base 4 is internally provided with arc-shaped slot 18, the arc-shaped slot 18 is internally provided with sliding block 19 in sliding mode, the sliding block 19 is elastically provided with abutting block 20, the sidewall of the arc-shaped slot 18 is provided with avoiding slot 21 matched with the abutting block 20, transmission rope 22 is arranged between the sliding block 19 and the toothed plate 16, the abutting block 20 is located on the rotating stroke of the transmission rod 11, specifically, the gear 15 is fixedly connected with the end of the rotating shaft 8, the toothed plate 16 comprises meshing section and sliding section arranged below the meshing section, the meshing section is in meshing with the gear 15, the sliding seat 17 is fixedly connected with the side of the circular calibration plate 2, and the sliding seat 17 is internally provided with sliding hole matched with the sliding section, the sliding section is in sliding connection with the sliding hole, so that the toothed plate 16 can vertically slide, the arc-shaped slot 18 is arranged on the inner sidewall of the circular ring section 401, and the sidewall of the arc-shaped slot 18 is provided with third spring 23 between the sliding block 19, the transmission rope 22 is preferably a metal material with low ductility, one end of the transmission rope 22 is fixedly connected with the sliding block 19, the other end of the transmission rope 22 is fixedly connected with the bottom end of the sliding section, and the circular ring section 401 is internally provided with guide hole matched with the transmission rope 22, so that the transmission rope 22 can slide in the guide hole, the sliding block 19 is internally provided with movable slot 24, the abutting block 20 is arranged in the movable slot 24 in sliding mode, the abutting block 20 is in cross shape, the fourth spring 25 is arranged between the movable slot 24 and the short side of the cross-shaped abutting block 20, and the abutting block 20 is provided with wedge surface on the end close to the central axis of the disc 3, the other end is in abutment with the sidewall of the arc-shaped slot 18, and the wedge surface of the abutting block 20 is located on the movement stroke of the end of the transmission rod 11, when the sliding block 19 slides to the end of the stroke, the abutting block 20 is coaxial with the avoiding slot 21, the sidewall of the groove 1301 is provided with through groove 1303 for the horizontal edge of the unlocking block 12 to pass through, when the baffle 5 is in the first position, the transmission rope 22 is in a relaxed state, when the baffle 5 is in the second position, the transmission rope 22 is in a straightened state, the arrangement is used for continuing to control the rotation of the transmission rod 11 after the target circular calibration plate 2 is shot, at this time, the horizontal edge of the unlocking block 12 will pass out of the through groove 1303, that is, the unlocking block 12 is away from the locking block 7 at this time, the locking block 7 is automatically reset under the action of the first spring 9, in the process of rotating the transmission rod 11, the end of the transmission rod 11 is in abutment with the wedge surface of the abutting block 20, because the abutting block 20 is in abutment with the sidewall of the arc-shaped slot 18, therefore, the abutting block 20 cannot slide along the movable slot 24 at this time, the abutting block 20 and the sliding block 19 can only slide along the arc-shaped slot 18 at this time, and the third spring 23 is stretched, in the process of sliding the sliding block 19,When the sliding block 19 slides to the other end of the arc-shaped slot 18, the baffle 5 is passively switched from the second position to the first position (in the process of switching, the bottom end of the baffle 5 abuts against the wedge surface of the locking block 7, so that the locking block 7 moves downward and extrudes the first spring 9, and after abutting, the locking block 7 is automatically reset under the elastic force of the first spring 9, so as to fix the baffle 5 at the first position), at this time, the abutting block 20 coincides with the avoiding slot 21, and the abutting of the transmission rod 11 and the wedge surface of the abutting block 20 makes the abutting block 20 slide along the movable slot 24 and insert into the avoiding slot 21, and simultaneously extrude the fourth spring 25 to realize avoidance, so that the transmission rod 11 can continue to rotate, and after the abutting of the transmission rod 11 and the abutting block 20 is completed, the abutting block 20 is extracted from the avoiding slot 21 under the elastic force of the fourth spring 25, at this time, the elastic force of the third spring 23 is released, so that the sliding block 19 reversely slides along the arc-shaped slot 18 to realize the automatic reset of the sliding block 19.

[0068] Further, the limiting portion 26 is arranged on the circular calibration plate 2, specifically, the limiting portion 26 is arranged at the top of the circular calibration plate 2 and between the two extending portions, and is located in the rotating stroke of the baffle 5, so as to prevent the baffle 5 from rotating excessively.

[0069] As another embodiment of the present application, the fixing seat 10 is provided with a fixing groove 27, and the three-dimensional scanner 1 is arranged in the fixing groove 27. The fixing seat 10 is elastically provided with a plurality of limiting blocks 28, which are uniformly arranged on the fixing seat 10 and abut against the three-dimensional scanner 1. The unlocking assembly is arranged to release the abutting effect of the limiting blocks 28 and the three-dimensional scanner 1. Specifically, the fixing groove 27 is arranged at the top end of the fixing seat 10 and has a size suitable for the three-dimensional scanner 1. The cross section of the three-dimensional scanner 1 is in the shape of an I-beam, that is, the bottom end of the three-dimensional scanner 1 protrudes from the body. The limiting block 28 includes a first segment arranged horizontally and a second segment arranged vertically. The fifth spring 29 is arranged between the second segment and the fixing seat 10. The unlocking assembly is a reciprocating driving assembly such as an electric push rod. When the fifth spring 29 is in a natural state, the first segment of the limiting block 28 extends into the fixing groove 27. When the three-dimensional scanner 1 is installed, the unlocking assembly controls the limiting block 28 to move away from the center axis of the disc 3 and press the fifth spring 29, so that the first segment is extracted from the fixing groove 27. The three-dimensional scanner 1 is placed in the fixing groove 27, and then the force of the unlocking assembly is removed. The limiting block 28 is automatically reset under the elastic force of the fifth spring 29. At this time, the lower surface of the limiting block 28 abuts against the upper surface of the I-beam bottom edge, so that the three-dimensional scanner 1 can be fixed in the fixing groove 27 to complete the installation of the three-dimensional scanner 1. When the three-dimensional scanner 1 needs to be taken out of the fixing groove 27, the unlocking assembly controls the limiting block 28 to move away from the center axis of the disc 3 to release the limiting effect of the limiting block 28 on the three-dimensional scanner 1, so that the three-dimensional scanner 1 can be taken out of the fixing groove 27.

[0070] As an alternative to the above embodiment, the unlocking assembly comprises a transmission frame 30 which is slidingly sleeved on the fixed seat 10, the transmission frame 30 is provided with a first abutting portion 31 and a second abutting portion 32, the transmission rod 11 is slidingly provided with a sliding plate 33, the sliding plate 33 is provided with a relief hole 34 which is matched with the unlocking block 12, the relief hole 34 makes the sliding plate 33 not interfere with the end of the unlocking block 12 when the sliding plate 33 slides on the upper surface of the transmission rod 11, the sliding plate 33 is provided with a third abutting portion 35, the second abutting portion 32 is located on the movement stroke of the third abutting portion 35, the base 4 is provided with an abutting plate 36, the abutting plate 36 is located on the movement stroke of the sliding plate 33, specifically, the transmission frame 30 is a square frame which is sleeved on the outer circumferential surface of the fixed seat 10, the number of the first abutting portions 31 corresponds to the number of the limiting blocks 28, the first abutting portions 31 are arranged on the upper surface of the transmission frame 30, and the top end of the first abutting portion 31 and the bottom end of the second section are both provided with a wedge surface, the upper surface of the transmission rod 11 is provided with a sliding groove 37, the lower part of the sliding plate 33 is provided with a convex portion, the convex portion is slidingly connected with the sliding groove 37, and the sixth spring 38 is arranged between the convex portion and the side wall of the sliding groove 37, the wedge surfaces are arranged on the second abutting portion 32 and the third abutting portion 35, the arc surface is arranged on the end of the sliding plate 33 which is away from the third abutting portion 35 and the end of the abutting plate 36 which is close to the central axis of the disc 3, the arc surface of the abutting plate 36 is located on the movement stroke of the arc surface of the sliding plate 33, and the abutting plate 36 is located between the first circular calibration plate 2 (i.e. Figure 4 the circular calibration plate 2 which is located in the shooting area of the three-dimensional scanner 1) and the last circular calibration plate 2 (which is located Figure 4The effect of the arrangement between the left side of the first circular calibration plate 2 and the right side of the last circular calibration plate 2 is that, when the three-dimensional scanner 1 finishes shooting the last circular calibration plate 2, the fixed seat 10 continues to rotate under the control of the power assembly, in the process of rotation, the arc surface of the sliding plate 33 abuts against the arc surface of the abutting plate 36, and stops when the sliding plate 33 and the abutting plate 36 are coaxial, in the process of abutting, the sliding plate 33 and the third abutting part 35 are pushed to slide in the direction of the second abutting part 32, and the sixth spring 38 is extruded, in the process of sliding, the third abutting part 35 abuts against the second abutting part 32, thereby driving the transmission frame 30 and the first abutting part 31 to move upwards, the wedge surfaces of the plurality of first abutting parts 31 abut against the wedge surfaces of the plurality of second sections respectively, thereby making the plurality of limiting blocks 28 move synchronously in the direction away from the central axis of the fixed groove 27, to achieve passive unlocking of the three-dimensional scanner 1, so that the three-dimensional scanner 1 after calibration can be taken out of the fixed groove 27, and since the sliding plate 33 stops when rotating to be coaxial with the abutting plate 36, the limiting block 28 also remains in this state, so that another three-dimensional scanner 1 that needs to be calibrated can be placed directly inside the fixed groove 27, then the transmission rod 11 is controlled to rotate, when the transmission rod 11 is away from the abutting plate 36, the sliding plate 33 and the third abutting part 35 move in the direction away from the second abutting part 32 under the action of the elastic force of the sixth spring 38, at this time, the transmission frame 30 is automatically reset under the action of its own gravity, and the limiting block 28 is automatically reset under the action of the fifth spring 29, to achieve passive locking of the three-dimensional scanner 1.

[0071] Further, the top end of the fixed groove 27 is configured with an open mouth, that is, the opening end of the fixed groove 27 is larger, so that the three-dimensional scanner 1 is easier to be placed inside the fixed groove 27, to facilitate installation of the three-dimensional scanner 1.

[0072] The above only describes certain exemplary embodiments of the application by way of illustration, and it is self-evident that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the application. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the application.

Claims

1. A method for sorting marker circles, characterized in that, Comprise the following steps: S1: obtaining a calibration image by a camera to be calibrated; S2: image preprocessing; S3: marker circle extraction; S4: marker circle sub-pixel contour extraction; S5: marker circle sorting; S6: camera calibration; An optical three-dimensional scanning measuring device for realizing the calibration process of a three-dimensional scanner containing a camera inside by the movement of the camera, comprising a base and a disc rotatingly arranged on the base, a three-dimensional scanner being arranged on the disc, a plurality of circular calibration boards being arranged on the base, and the plurality of circular calibration boards being located in the shooting area in the rotating stroke of the three-dimensional scanner; A forced centering mechanism is arranged between the three-dimensional scanner and the circular calibration board for making the three-dimensional scanner and the circular calibration board face each other; Further comprising a power assembly for driving the disc to rotate; The forced centering mechanism comprises a blocking assembly for shielding the circular calibration board and a driving member for driving the blocking assembly to move, and based on the three-dimensional scanner facing the target circular calibration board, the blocking assembly unblocks the circular calibration board; The blocking assembly comprises a baffle rotatingly arranged on the circular calibration board, the baffle having a first position for shielding the circular calibration board and a second position for opening the circular calibration board, and a torsion spring being arranged between the baffle and the circular calibration board, and a locking block being elastically arranged on the base, the baffle being attached to the circular calibration board when the baffle is in the first position, and the locking block being located in the rotating stroke of the baffle when the baffle is in the second position; The disc is provided with a fixing seat, the driving member comprises a transmission rod, the transmission rod being fixedly connected to the fixing seat, an unlocking block being elastically arranged on the transmission rod, a plurality of centering blocks being arranged on the base, the plurality of centering blocks corresponding to the plurality of circular calibration boards one by one, a recess being formed in the centering block and being matched with the unlocking block, the locking block being located in the recess, and an inclined surface being arranged on the centering block and being located in the movement stroke of the unlocking block; The base is provided with a switching assembly for switching the baffle from the second position to the first position, the switching assembly comprising intermeshing gears and a toothed plate, the gears being fixedly connected to the baffle, a sliding seat being fixedly connected to the circular calibration board, the toothed plate being slidingly connected to the sliding seat, an arc-shaped groove being formed in the base, a sliding block being slidingly arranged in the arc-shaped groove, an abutting block being elastically arranged on the sliding block, an avoiding groove being formed in the sidewall of the arc-shaped groove and being matched with the abutting block, and a transmission rope being arranged between the sliding block and the toothed plate, the abutting block being located in the rotating stroke of the transmission rope.

2. The method of claim 1, wherein, In step S1, the circular calibration board is placed in the shooting area of the camera, and the position of the circular calibration board is adjusted to obtain pictures taken by the camera in various positions.

3. The method of claim 1, wherein, In step S2, the pictures taken by the camera are first filtered, then binarized, and finally all contours in the image are extracted based on the binarized image.

4. The method of claim 1, wherein, In step S3, all marker circle contours are screened out.

5. The method of claim 1, wherein, In step S4, according to the obtained mark circle contour, a sub-pixel level contour is calculated, and a circle center and a radius are fitted based on the sub-pixel level contour.

6. The method of claim 1, wherein, In step S5, all the mark circles are sorted, and the order of the mark circles is unified.

7. The method of claim 1, wherein In step S6, three-dimensional coordinates of the mark circle centers are established based on the actual physical size of the circular calibration board, and the camera is calibrated in combination with the fitted mark circle center coordinates.

8. A method of sorting a set of circular marks according to any one of claims 1 to 7, wherein, The circular calibration board has 9 rows, 11 columns, a center distance of 15 mm, and a precision of 0.01 mm.

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