Three-dimensional calibration plate, system and calibration method suitable for laser 3D vision

Abstract

The present application provides a three-dimensional calibration plate suitable for laser 3D vision, which is an image acquisition object of a line laser scanning 3D camera and is used in the field of mechanical 3D vision. The plate body of the calibration plate itself is divided into a camera reference part, a view stitching part and a coordinate positioning part. Through the above-mentioned camera reference part, the camera calibration problem that the X direction and the Y direction need to be highly perpendicular to each other for camera shooting is solved through the camera reference part, the problem that the camera shooting accuracy is inversely proportional to the field of view is solved through image stitching, and the coordinate system of the camera is converted by the coordinate positioning part to solve the correspondence problem of taking points in the image of the actual product, and then guiding the device to actually execute on the product.

Description

Technical Field

[0001] The present application relates to the field of mechanical 3D vision technology, and in particular to a three-dimensional calibration plate suitable for laser 3D vision. Background Art

[0002] The existing line laser scanning 3D camera imaging action requires a linear scanning action to continuously capture images of the scanned object, thereby forming a 3D point cloud image. Figure 1 As shown, the line laser scanning 3D camera performs precise linear motion along the Y direction;

[0003] After scanning the 3D point cloud image, the image is highly consistent with the shape of the scanned object, so the scanned object can be directly processed for secondary processing, such as size detection, defect detection, or positioning guidance for cutting, grinding or spraying; However, the above-mentioned line laser scanning 3D camera needs to meet the following conditions in order to achieve image acquisition and meet project requirements:

[0004] 1. The X direction of the camera should be highly perpendicular to the Y direction, as shown in the following figure. Figure 1 The perpendicular relationship between the X direction and the Y direction;

[0005] 2. The accuracy and field of view of a camera are usually inversely proportional to each other, such as Figure 1 Dashed line: The wider the dotted line spreads, the larger the field of view of the camera, but the resolution will be reduced accordingly. That is, the larger the field of view, the lower the accuracy. In this case, when a project requires a large field of view and high accuracy, it will not be possible to take it into account.

[0006] 3. When the camera scans an object, it has a virtual 3D coordinate system built inside and images the object in the 3D coordinate system. However, the virtual coordinate system built into the camera cannot determine the position of the camera itself on the mechanical coordinate system of the device, so it is impossible to guide the device for the above object.

[0007] Usually the above conditions are encountered in every project, and the only difference is whether the error can reach an acceptable range. However, this greatly limits the maximum performance of the line laser scanning 3D camera hardware and results in a large waste of resources. Summary of the invention

[0008] The present application aims to achieve the technical effects of laser 3D vision hardware calibration, image stitching, and coordinate system conversion to solve the problem that camera shooting requires calibration in the X direction and the Y direction to be highly perpendicular, solve the problem that the camera shooting accuracy is inversely proportional to the field of view through image stitching, and solve the problem of fixed-point operation shooting through coordinate system conversion, and provide a three-dimensional calibration plate suitable for laser 3D vision.

[0009] This application adopts the following technical means to solve the technical problem:

[0010] The present application proposes a three-dimensional calibration plate suitable for laser 3D vision, which is an image acquisition object of a line laser scanning 3D camera. The calibration plate itself is divided into a camera reference part, a view stitching part and a coordinate positioning part, wherein:

[0011] The camera reference part is located on one side of the plate body of the calibration plate, and has a first reference inclined plane block, a second reference inclined plane block and a reference plane block. The first reference inclined plane block and the second reference inclined plane block are fixedly arranged on both sides of the reference plane block. The inclined planes of the first reference inclined plane block and the second reference inclined plane block have preset inclinations but in opposite directions, and form a trapezoidal shape with the plane of the reference plane block.

[0012] The view splicing portion comprises a first splicing slot, a second splicing slot and a circular hole array, wherein the circular hole array is arranged through the middle position of the plate body of the calibration plate, the first splicing slot and the second splicing slot are respectively arranged on the calibration plate at the two sides of the circular hole array, the first splicing slot and the second splicing slot both have a first splicing inclined surface and a second splicing inclined surface, the inclined surfaces of the first splicing inclined surface and the second splicing inclined surface have a preset slope but are in opposite directions, and the first splicing slot and the second splicing slot are arranged on the calibration plate through a triangular groove formed by the intersection of the first splicing inclined surface and the second splicing inclined surface;

[0013] The coordinate positioning part includes a plurality of positioning posts, small holes are formed on the top surfaces of the positioning posts, and the plurality of positioning posts are respectively fixed at the corner points of the calibration plate.

[0014] Furthermore, the first reference inclined plane block and the second reference inclined plane block have inclined planes with the same inclination but opposite directions, and form an isosceles trapezoidal shape with the plane of the reference plane block.

[0015] Furthermore, the first splicing bevel and the second splicing bevel have equal inclinations but opposite directions, and the first splicing slot and the second splicing slot are provided on the calibration plate through an isosceles triangular groove formed by the intersection of the first splicing bevel and the second splicing bevel.

[0016] Furthermore, the first splicing slot and the second splicing slot are respectively arranged at two sides of the circular hole array and are perpendicular to the camera reference part.

[0017] Furthermore, the first splicing slot and the second splicing slot both have a plurality of triangular grooves spliced ​​to each other.

[0018] Furthermore, openings are respectively provided through the middle portions of the first splicing slot and the second splicing slot.

[0019] The present application provides a three-dimensional calibration system suitable for laser 3D vision, a line laser scanning 3D camera, a motion mechanism and the above-mentioned three-dimensional calibration plate suitable for laser 3D vision;

[0020] The motion mechanism drives the line laser scanning 3D camera to perform linear motion;

[0021] The calibration plate is located below the laser collection end of the line laser scanning 3D camera;

[0022] The line laser scanning 3D camera collects the image of the calibration plate to perform camera calibration, splicing calibration and coordinate calibration.

[0023] The present application also proposes a camera calibration method for a three-dimensional calibration plate suitable for laser 3D vision, wherein the steps of collecting an image of the calibration plate by a line laser scanning 3D camera for camera calibration include:

[0024] S11, the camera sequentially scans the first reference inclined plane of the first reference inclined plane block, the reference plane of the reference plane block, and the second reference inclined plane of the second reference inclined plane block of the calibration plate along a straight line to sequentially acquire imaging images of the first reference inclined plane, the reference plane, and the second reference inclined plane;

[0025] S12, using a virtual imaging model preset in the camera to process the imaging images of the first reference inclined plane, the reference plane, and the second reference inclined plane to obtain a collection length of the reference plane in the imaging image;

[0026] S13, determining whether the acquisition length is consistent with the actual length of the reference plane;

[0027] S14, if not, proceed to the next step, if yes, determine that the cameras are absolutely parallel;

[0028] S15, determining the deviation angle coefficient between the collected length and the actual length;

[0029] S16, adjusting the position of the camera accordingly according to the deviation angle coefficient.

[0030] Furthermore, the step of collecting the image of the calibration plate by the line laser scanning 3D camera for stitching calibration includes:

[0031] S21, when the camera moves to the first splicing slot, the camera scans the first splicing inclined surface and the second splicing inclined surface of the first splicing slot of the calibration plate along a straight line to obtain an imaging image of the first splicing inclined surface and the second splicing inclined surface of the first splicing slot;

[0032] S22, when the camera moves to the circular hole array, the camera scans the circular holes of each row of the circular hole array along a straight line to obtain images of each row of circular holes, and as the camera moves in a straight line, the camera gradually compares whether the images of each row of circular holes completely overlap, and outputs the circular hole stitching result;

[0033] S23, when the camera moves to the second splicing slot, the camera scans the first splicing bevel and the second splicing bevel of the second splicing slot of the calibration plate along a straight line to obtain an image of the first splicing bevel and the second splicing bevel of the second splicing slot, and then determines whether the image of the first splicing bevel and the second splicing bevel of the first splicing slot completely overlaps with the image of the first splicing bevel and the second splicing bevel of the second splicing slot, and outputs the slot splicing result;

[0034] S24, if the circular hole stitching result and the slot stitching result are completely overlapped, it is determined that the camera will not have a viewing angle deviation during the straight line movement, if not, proceed to the next step;

[0035] S25, obtaining a first deviation value of the comparison of the imaging images of each row of circular holes in step S22, and obtaining a second deviation value of the comparison of the imaging images of the first splicing bevel and the second splicing bevel of the first splicing slot in step S23 with the imaging images of the first splicing bevel and the second splicing bevel of the second splicing slot;

[0036] S26, adjusting the camera accordingly according to the first deviation value and the second deviation value.

[0037] Furthermore, the step of collecting the image of the calibration plate by the line laser scanning 3D camera for coordinate calibration includes:

[0038] S31, the camera sequentially scans the positioning posts at the corner points of the calibration plate to obtain an image of the positioning posts;

[0039] S32, the camera has a built-in virtual 3D coordinate, the Y axis of the virtual 3D coordinate is the linear motion direction of the camera, the X axis is perpendicular to the Y axis, the imaging image of the positioning column is placed in the virtual 3D coordinate, and punctuation is formed in the virtual 3D coordinate according to the small hole on the top surface of the positioning column;

[0040] S33, the motion mechanism controlling the movement of the camera controls the camera accordingly according to the punctuation points formed in the virtual 3D coordinates.

[0041] The present application provides a three-dimensional calibration plate suitable for laser 3D vision, which has the following beneficial effects:

[0042] The present application proposes a three-dimensional calibration plate suitable for laser 3D vision, which is an image acquisition object of a line laser scanning 3D camera. The plate body of the calibration plate itself is divided into a camera reference part, a view stitching part and a coordinate positioning part, wherein the camera reference part is located on one side of the plate body of the calibration plate, and has a first reference bevel block, a second reference bevel block and a reference plane block, the first reference bevel block and the second reference bevel block are fixedly arranged on both sides of the reference plane block, the bevels of the first reference bevel block and the second reference bevel block have a preset slope but in opposite directions and form a trapezoidal shape with the plane of the reference plane block, and the hardware calibration of the camera 3D vision is realized through the camera reference part; the view stitching part has a first stitching slot, a second stitching slot and a circular hole array, the circular hole array is arranged through the middle position of the plate body of the calibration plate, and the first stitching slot and the second stitching slot are respectively arranged at the mark on both sides of the circular hole array. On the fixed plate, the first splicing slot and the second splicing slot both have a first splicing bevel and a second splicing bevel, the bevels of the first splicing bevel and the second splicing bevel have a preset slope but in opposite directions, the first splicing slot and the second splicing slot are provided on the calibration plate through a triangular groove formed by the intersection of the first splicing bevel and the second splicing bevel, and the calibration of the camera image splicing is achieved through the first splicing slot, the second splicing slot and the circular hole array; the coordinate positioning part includes a plurality of positioning columns, and small holes are opened on the top surface of the positioning columns, and the plurality of positioning columns are respectively fixed to the various corner positions of the calibration plate, and the 3D coordinates are calibrated inside the camera through the plurality of positioning columns to facilitate the subsequent camera control; in summary, the calibration problem that the camera shooting requires the X direction and the Y direction to be highly perpendicular is solved, the problem that the camera shooting accuracy is inversely proportional to the field of view is solved through image stitching, and the problem of fixed-point operation shooting is solved through coordinate system conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The schematic diagram of the camera moving position in the prior art;

[0044] Figure 2 This is a structural schematic diagram of an embodiment of a three-dimensional calibration plate suitable for laser 3D vision proposed in this application;

[0045] Figure 3 This is a schematic structural diagram of another embodiment of a three-dimensional calibration plate suitable for laser 3D vision proposed in this application;

[0046] Figure 4 This is a structural schematic diagram of an embodiment of a three-dimensional calibration plate and camera movement direction suitable for laser 3D vision proposed in this application;

[0047] Figure 5 A perspective view of a side surface of an embodiment of a three-dimensional calibration plate suitable for laser 3D vision proposed in this application;

[0048] Figure 6 This is a structural block diagram of an embodiment of a three-dimensional calibration system applicable to laser 3D vision proposed in this application;

[0049] Figure 7 A schematic diagram of a camera calibration process in an embodiment of a camera calibration method for a three-dimensional calibration plate applicable to laser 3D vision provided in the present application;

[0050] Figure 8 A schematic diagram of camera stitching calibration in an embodiment of a camera calibration method for a three-dimensional calibration plate suitable for laser 3D vision provided in this application;

[0051] Fig. 9 A schematic diagram of a coordinate calibration process in an embodiment of a camera calibration method for a three-dimensional calibration plate applicable to laser 3D vision provided in the present application;

[0052] The implementation, functional features and advantages of the present application will be further described in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0053] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0054] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0055] It should be noted that the terms "include", "comprises" and "have" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices. In the claims, specification and drawings of the present application, relational terms such as "first" and "second" are merely used to distinguish one entity / operation / object from another entity / operation / object, and do not necessarily require or imply any such actual relationship or order between these entities / operations / objects.

[0056] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0057] Reference Figure 2 and attached Figure 3 , is a schematic structural diagram of a three-dimensional calibration plate suitable for laser 3D vision in an embodiment of the present application;

[0058] The present application proposes a three-dimensional calibration plate suitable for laser 3D vision, which is an image acquisition object for a line laser scanning 3D camera;

[0059] The calibration plate itself is divided into a camera reference part 1, a view stitching part 2 and a coordinate positioning part 3, as shown in the attached figure. Figure 2 Shown by the dashed line.

[0060] in,

[0061] The camera reference part 1 is located on one side of the plate body of the calibration plate, and has a first reference inclined plane block 11, a second reference inclined plane block 13 and a reference plane block 12. The first reference inclined plane block 11 and the second reference inclined plane block 13 are fixedly arranged on both sides of the reference plane block 12. The inclined planes of the first reference inclined plane block 11 and the second reference inclined plane block 13 have preset inclinations but in opposite directions, and form a trapezoidal shape with the plane of the reference plane block 12.

[0062] In a preferred embodiment, the first reference inclined plane block 11 and the second reference inclined plane block 13 have the same inclination but opposite directions, and form an isosceles trapezoidal shape with the plane of the reference plane block 12 .

[0063] As attached Figure 3 As shown, on the camera reference portion 1 on one side of the plate body of the calibration plate, there are three step-like raised portions. It should be noted that in some expandable cases, the number of step-like raised portions can be set; one of the raised portions is composed of a first reference bevel block 11, a second reference bevel block 13 and a reference plane block 12.

[0064] Specifically, the camera reference part 1 of the calibration plate is used to calibrate whether the camera is absolutely parallel. First, the reference plane of the reference plane block 12 of the calibration plate needs to be grinded to a flatness within 0.01 mm. The flatness is the inclination coefficient of the reference plane. A micrometer is used to calibrate on the reference plane to make the camera parallel to the reference plane. Then, the camera is tested by measuring the inclined plane of the first reference inclined plane block 11 and the inclined plane of the second reference inclined plane block 13. It can be understood that the two inclined planes are set on both sides of the reference plane. At this time, the acquisition length of the reference plane is calculated by the virtual imaging model inside the camera. The acquisition length calculation method of the virtual imaging model is:

[0065] (1) Extend the two inclined planes until they intersect (see Appendix Figure 5 );

[0066] (2) A triangulation algorithm is built into the virtual imaging model. The extended lengths of the two inclined planes are imported into the triangulation algorithm to calculate the length of the plane and obtain the acquisition length of the reference plane.

[0067] After the camera obtains the above-mentioned acquisition length, it needs to be compared with the actual length of the reference plane of the calibration plate, that is, the acquisition length is compared with the actual length. For example, if the acquisition length is 11cm and the actual length is 10cm, it can be determined that the camera is tilted, and then the corresponding camera adjustment can be made.

[0068] Advantages: This measurement method can avoid the measurement error caused by the X-resolution limitation of the line laser scanning camera. The imaging principle has the highest resolution and repeatability in the Z direction, so this calculation can bring out the highest performance of the camera. However, the line laser scanning cameras on the market all use the laser triangulation imaging principle to directly scan the length of the reference plane of the triangle. In this way, due to the influence of the camera resolution, the camera itself cannot determine the length very well, so the scanned length is inaccurate, and the comparison result between the length and the actual length is also inaccurate.

[0069] The calibration plate also has a view splicing portion 2, which includes a first splicing slot 21, a second splicing slot 22 and a circular hole array 23. The circular hole array 23 (attached Figure 3 The circular holes within the range selected by the dotted line are referred to as the circular hole array 23) and are arranged through the middle position of the plate body of the calibration plate. The first splicing slot 21 and the second splicing slot 22 are respectively arranged on the calibration plate at the two sides of the circular hole array 23. The first splicing slot 21 and the second splicing slot 22 both have a first splicing inclined surface and a second splicing inclined surface. The inclined surfaces of the first splicing inclined surface and the second splicing inclined surface have a preset slope but are in opposite directions. The first splicing slot 21 and the second splicing slot 22 are arranged on the calibration plate through a triangular groove formed by the intersection of the first splicing inclined surface and the second splicing inclined surface;

[0070] In a preferred embodiment, the first splicing bevel and the second splicing bevel have the same slope but opposite directions, and the first splicing slot 21 and the second splicing slot 22 are provided on the calibration plate through an isosceles triangular groove formed by the intersection of the first splicing bevel and the second splicing bevel. In addition, the first splicing slot 21 and the second splicing slot 22 are respectively provided at both sides of the circular hole array 23 and are perpendicular to the camera reference part 1. Moreover, the first splicing slot 21 and the second splicing slot 22 both have a plurality of triangular grooves spliced ​​with each other.

[0071] Specifically, the camera performs stitching calibration of the scanned image through the view stitching unit 2, and the scanned image acquisition after calibration is synthesized in the form of stitching, which can effectively solve the inverse ratio problem between the field of view and the resolution, and give full play to the original performance of the camera; the first stitching slot 21 and the second stitching slot 22 are respectively arranged on both sides of the circular hole array 23, and the first stitching slot 21 and the second stitching slot 22 are both provided with two triangular grooves located on the calibration plate (refer to the attached Figure 2 ), it should be noted that the number of triangular grooves is configured by the technician.

[0072] Reference Figure 4 , is a schematic diagram of a calibration plate according to an embodiment of the present application;

[0073] During the specific implementation process, the camera moves along the Y direction to scan the calibration plate, and first obtains the corresponding imaging images of the first reference plane 211, the first splicing bevel 212 and the second splicing bevel 214 of the first splicing slot 21, and the second reference plane 213 according to the mobile scanning; then, the camera scans and obtains the corresponding imaging images of the third reference plane 221, the first splicing bevel 222 and the second splicing bevel 224 of the second splicing slot 22, and the fourth reference plane 223; finally, the imaging images of the first reference plane and the third reference plane are overlapped to determine whether they are completely overlapped, the imaging images of the first splicing bevel and the second splicing bevel of the first splicing slot 21 and the first splicing bevel and the second splicing bevel of the second splicing slot 22 are overlapped to determine whether they are completely overlapped, and the imaging images of the second reference plane and the fourth reference plane are overlapped to determine whether they are completely overlapped; if they can be completely overlapped, it is determined that the camera will not deviate during the movement, and the deviation includes the deviation of the upper and lower positions, the deviation in the rotation direction, etc. If they cannot completely overlap, it is determined that the camera has deviated during movement and corresponding adjustments are required. The above adjustments include manual adjustments and / or mechanical adjustments, which are not elaborated in this application.

[0074] It should be noted that the circular hole array 23 is also used for calibration of image stitching, such as Figure 4 The circular holes in each row are overlapped, which is the same as the above principle and will not be described in detail here.

[0075] Benefits:

[0076] Since the intersection of the spatial slope and the spatial plane is the easiest to identify the coplanarity and overlap of the two images, the gap is measured and the stitching data is adjusted, which greatly reduces the calculation process; since the X-direction resolution of the camera itself will be limited by the field of view (the X-direction resolution of the camera with a large field of view will be reduced. Resolution = field of view L / 1280). After the circular hole is imaged, an algorithm can be used to collect the position of the center point of the circular hole. In this way, the influence of the X-direction resolution is calculated by increasing the number of samples (that is, the size of the circular hole). After capturing the end points of the two circular holes, the three-dimensional space distance value between the two center points is calculated and compared with the theoretical circular hole distance in the actual finishing drawing. After debugging to the extent possible consistent with the theoretical distance, it means that the image stitching in the X direction has been completed. Therefore, this method is used to calculate the stitching distance in the X direction, and the influence of the X direction is also minimized. The highest possible precision image can be stitched out under the limited conditions of the online laser scanning camera.

[0077] In another embodiment, openings are respectively provided through the middle parts of the first splicing slot 21 and the second splicing slot 22. On the premise of reducing the material of the calibration plate, new judgment conditions can be introduced to determine whether the two openings completely overlap.

[0078] The calibration plate further has a coordinate positioning part 3, which includes a plurality of positioning posts 31. Small holes 32 are formed on the top surfaces of the positioning posts 31. The plurality of positioning posts 31 are respectively fixed at the corner points of the calibration plate.

[0079] Specifically, the coordinate positioning unit 3 is a coordinate system for aligning the camera. It can be understood that a virtual 3D coordinate system is built into the camera. After the camera scans the calibration plate, the image of the calibration plate is imaged on the virtual 3D coordinate system. However, at this time, the camera does not know where its own position is in the coordinate system. The image of the calibration plate is also sent by the camera to the motion mechanism, and the image of the calibration plate is imaged on the motion mechanism. Therefore, the motion mechanism can determine a mechanical coordinate system, on which there are the camera numbers and the numbers of the small holes 32 of the positioning columns 31 of the calibration plate. The motion mechanism can shoot the designated position of the calibration plate at the camera fixed point.

[0080] In summary, the present application proposes a three-dimensional calibration plate suitable for laser 3D vision, which is an image acquisition object of a line laser scanning 3D camera. The plate body of the calibration plate itself is divided into a camera reference part 1, a view stitching part 2 and a coordinate positioning part 3, wherein the camera reference part 1 is located on one side of the plate body of the calibration plate, and has a first reference bevel block 11, a second reference bevel block 13 and a reference plane block 12, the first reference bevel block 11 and the second reference bevel block 13 are fixedly arranged on both sides of the reference plane block 12, the bevels of the first reference bevel block 11 and the second reference bevel block 13 have a preset slope but in opposite directions, and form a trapezoidal shape with the plane of the reference plane block 12, and the hardware calibration of the camera 3D vision is realized through the camera reference part 1; the view stitching part 2 has a first stitching slot 21, a second stitching slot 22 and a circular hole array 23, the circular hole array 23 is arranged through the middle position of the plate body of the calibration plate, and the first stitching slot 21 and the second stitching slot 22 are respectively arranged in the circular hole array On the calibration plate at the two sides of 23, the first splicing slot 21 and the second splicing slot 22 both have a first splicing bevel and a second splicing bevel, the bevels of the first splicing bevel and the second splicing bevel have a preset slope but in opposite directions, the first splicing slot 21 and the second splicing slot 22 are provided on the calibration plate through a triangular groove formed by the intersection of the first splicing bevel and the second splicing bevel, and the calibration of the camera image splicing is realized through the first splicing slot 21, the second splicing slot 22 and the circular hole array 23; the coordinate positioning part 3 includes a plurality of positioning columns 31, and a small hole 32 is opened on the top surface of the positioning column 31. The plurality of positioning columns 31 are respectively fixed to each corner point position of the calibration plate, and the 3D coordinates are calibrated inside the camera through the plurality of positioning columns 31, so as to facilitate the later camera control; in summary, the calibration problem that the camera shooting requires the X direction and the Y direction to be highly perpendicular is solved, the problem that the camera shooting accuracy is inversely proportional to the field of view is solved through image stitching, and the problem of fixed-point operation shooting is solved through coordinate system conversion.

[0081] Reference Figure 6 , is a structural block diagram of a three-dimensional calibration system suitable for laser 3D vision, which includes a line laser scanning 3D camera, a motion mechanism and the above-mentioned three-dimensional calibration plate suitable for laser 3D vision;

[0082] The motion mechanism drives the linear laser scanning 3D camera to perform linear motion;

[0083] The calibration plate is located below the laser collection end of the line laser scanning 3D camera;

[0084] The line laser scanning 3D camera collects images of the calibration plate for camera calibration, stitching calibration and coordinate calibration.

[0085] From the above, it can be seen that the present application uses the camera to collect the image of the calibration plate for camera calibration, stitching calibration and coordinate calibration, therefore:

[0086] Reference Figure 7 , which is a flow chart of a camera calibration method for a three-dimensional calibration plate suitable for laser 3D vision provided in the present application, wherein the steps of acquiring an image of the calibration plate by a line laser scanning 3D camera for camera calibration include:

[0087] S11, the camera sequentially scans the first reference inclined surface of the first reference inclined surface block 11, the reference plane of the reference plane block 12, and the second reference inclined surface of the second reference inclined surface block 13 of the calibration plate along a straight line to sequentially acquire imaging images of the first reference inclined surface, the reference plane, and the second reference inclined surface;

[0088] S12, using a virtual imaging model preset in the camera to process the imaging images of the first reference inclined surface, the reference plane, and the second reference inclined surface to obtain a collection length of the reference plane in the imaging image;

[0089] S13, determining whether the acquired length is consistent with the actual length of the reference plane;

[0090] S14, if not, proceed to the next step, if yes, determine that the cameras are absolutely parallel;

[0091] S15, determining the deviation angle coefficient between the collected length and the actual length;

[0092] S16, adjusting the position of the camera accordingly according to the deviation angle coefficient.

[0093] Reference Figure 8 , which is a flow chart of a camera calibration method for a three-dimensional calibration plate suitable for laser 3D vision provided in the present application, wherein the steps of collecting an image of the calibration plate by a line laser scanning 3D camera for stitching calibration include:

[0094] S21, when the camera moves to the first splicing slot 21, the camera scans the first splicing inclined surface and the second splicing inclined surface of the first splicing slot 21 of the calibration plate along a straight line to obtain an imaging image of the first splicing inclined surface and the second splicing inclined surface of the first splicing slot 21;

[0095] S22, when the camera moves to the circular hole array 23, the camera scans the circular holes of each row of the circular hole array 23 along a straight line to obtain the image of each row of circular holes, and as the camera moves in a straight line, the camera gradually compares whether the image of each row of circular holes completely overlaps, and outputs the circular hole stitching result;

[0096] S23, when the camera moves to the second splicing slot 22, the camera scans the first splicing bevel and the second splicing bevel of the second splicing slot 22 of the calibration plate along a straight line to obtain an image of the first splicing bevel and the second splicing bevel of the second splicing slot 22, and then determines whether the image of the first splicing bevel and the second splicing bevel of the first splicing slot 21 completely overlaps with the image of the first splicing bevel and the second splicing bevel of the second splicing slot 22, and outputs the slot splicing result;

[0097] S24, if the circular hole stitching result and the slot stitching result are completely overlapped, it is determined that the camera will not have a viewing angle deviation during the straight line movement process, if not, proceed to the next step;

[0098] S25, obtaining a first deviation value of the comparison of the imaging images of each row of circular holes in step S22, and obtaining a second deviation value of the comparison of the imaging images of the first splicing bevel and the second splicing bevel of the first splicing slot 21 in step S23 with the imaging images of the first splicing bevel and the second splicing bevel of the second splicing slot 22;

[0099] S26, adjusting the camera accordingly according to the first deviation value and the second deviation value.

[0100] Reference Fig. 9 , which is a flow chart of a camera calibration method for a three-dimensional calibration plate applicable to laser 3D vision provided in the present application, wherein the steps of collecting an image of the calibration plate by a line laser scanning 3D camera for coordinate calibration include:

[0101] S31, the camera sequentially scans the positioning posts 31 at the corner points of the calibration plate to obtain an image of the positioning posts 31;

[0102] S32, the camera has a built-in virtual 3D coordinate, the Y axis of the virtual 3D coordinate is the linear motion direction of the camera, the X axis is perpendicular to the Y axis, the image of the positioning column 31 is placed in the virtual 3D coordinate, and punctuation is formed in the virtual 3D coordinate according to the small hole 32 on the top surface of the positioning column 31;

[0103] S33, the motion mechanism controlling the movement of the camera controls the camera accordingly according to the punctuation points formed in the virtual 3D coordinates.

[0104] Although the embodiments of the present application have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A three-dimensional calibration plate suitable for laser 3D vision, which is an image acquisition object of a line laser scanning 3D camera, characterized in that: The calibration plate itself is divided into a camera reference part, a view stitching part and a coordinate positioning part, wherein: The camera reference part is located on one side of the plate body of the calibration plate, and has a first reference inclined plane block, a second reference inclined plane block and a reference plane block. The first reference inclined plane block and the second reference inclined plane block are fixedly arranged on both sides of the reference plane block. The inclined planes of the first reference inclined plane block and the second reference inclined plane block have preset inclinations but in opposite directions, and form a trapezoidal shape with the plane of the reference plane block. The view splicing portion comprises a first splicing slot, a second splicing slot and a circular hole array, wherein the circular hole array is arranged through the middle position of the plate body of the calibration plate, the first splicing slot and the second splicing slot are respectively arranged on the calibration plate at the two sides of the circular hole array, the first splicing slot and the second splicing slot both have a first splicing inclined surface and a second splicing inclined surface, the inclined surfaces of the first splicing inclined surface and the second splicing inclined surface have a preset slope but are in opposite directions, and the first splicing slot and the second splicing slot are arranged on the calibration plate through a triangular groove formed by the intersection of the first splicing inclined surface and the second splicing inclined surface; The coordinate positioning part includes a plurality of positioning posts, a small hole is opened on the top surface of the positioning posts, and the plurality of positioning posts are respectively fixed at the corner points of the calibration plate; The first reference inclined plane block and the second reference inclined plane block have the same inclination but opposite directions, and form an isosceles trapezoidal shape with the plane of the reference plane block; The first splicing bevel and the second splicing bevel have the same inclination but opposite directions, and the first splicing slot and the second splicing slot are arranged on the calibration plate through an isosceles triangle groove formed by the intersection of the first splicing bevel and the second splicing bevel.

2. The three-dimensional calibration plate suitable for laser 3D vision according to claim 1, characterized in that: The first splicing slot and the second splicing slot are respectively arranged at two sides of the circular hole array and are perpendicular to the camera reference part.

3. The three-dimensional calibration plate suitable for laser 3D vision according to claim 1, characterized in that: The first splicing slot and the second splicing slot both have a plurality of triangular grooves spliced ​​to each other.

4. The three-dimensional calibration plate suitable for laser 3D vision according to any one of claims 1 to 3, characterized in that: The middle parts of the first splicing slot and the second splicing slot are respectively penetrated by openings.

5. A three-dimensional calibration system suitable for laser 3D vision, characterized in that: It comprises a line laser scanning 3D camera, a motion mechanism and a three-dimensional calibration plate suitable for laser 3D vision as claimed in any one of claims 1 to 4; The motion mechanism drives the line laser scanning 3D camera to perform linear motion; The calibration plate is located below the laser collection end of the line laser scanning 3D camera; The line laser scanning 3D camera collects the image of the calibration plate to perform camera calibration, splicing calibration and coordinate calibration.

6. A camera calibration method for a three-dimensional calibration plate suitable for laser 3D vision, characterized in that: The steps of acquiring an image of a calibration plate for camera calibration by a line laser scanning 3D camera include: S11, the camera sequentially scans the first reference inclined plane of the first reference inclined plane block, the reference plane of the reference plane block, and the second reference inclined plane of the second reference inclined plane block of the calibration plate along a straight line to sequentially acquire imaging images of the first reference inclined plane, the reference plane, and the second reference inclined plane; S12, using a virtual imaging model preset in the camera to process the imaging images of the first reference inclined plane, the reference plane, and the second reference inclined plane to obtain a collection length of the reference plane in the imaging image; S13, determining whether the acquisition length is consistent with the actual length of the reference plane; S14, if not, proceed to the next step, if yes, determine that the cameras are absolutely parallel; S15, determining the deviation angle coefficient between the collected length and the actual length; S16: Adjust the position of the camera accordingly according to the deviation angle coefficient.

7. The camera calibration method of the three-dimensional calibration plate suitable for laser 3D vision according to claim 6, characterized in that: The step of collecting the image of the calibration plate by the line laser scanning 3D camera for stitching calibration includes: S21, when the camera moves to the first splicing slot, the camera scans the first splicing inclined surface and the second splicing inclined surface of the first splicing slot of the calibration plate along a straight line to obtain an imaging image of the first splicing inclined surface and the second splicing inclined surface of the first splicing slot; S22, when the camera moves to the circular hole array, the camera scans the circular holes of each row of the circular hole array along a straight line to obtain images of each row of circular holes, and as the camera moves in a straight line, the camera gradually compares whether the images of each row of circular holes completely overlap, and outputs the circular hole stitching result; S23, when the camera moves to the second splicing slot, the camera scans the first splicing bevel and the second splicing bevel of the second splicing slot of the calibration plate along a straight line to obtain an image of the first splicing bevel and the second splicing bevel of the second splicing slot, and then determines whether the image of the first splicing bevel and the second splicing bevel of the first splicing slot completely overlaps with the image of the first splicing bevel and the second splicing bevel of the second splicing slot, and outputs the slot splicing result; S24, if the circular hole stitching result and the slot stitching result are completely overlapped, it is determined that the camera will not have a viewing angle deviation during the straight line movement, if not, proceed to the next step; S25, obtaining a first deviation value of the comparison of the imaging images of each row of circular holes in step S22, and obtaining a second deviation value of the comparison of the imaging images of the first splicing bevel and the second splicing bevel of the first splicing slot in step S23 with the imaging images of the first splicing bevel and the second splicing bevel of the second splicing slot; S26, adjusting the camera accordingly according to the first deviation value and the second deviation value.

8. The camera calibration method of the three-dimensional calibration plate suitable for laser 3D vision according to claim 6, characterized in that: The step of collecting an image of a calibration plate by the line laser scanning 3D camera for coordinate calibration comprises: S31, the camera sequentially scans the positioning posts at the corner points of the calibration plate to obtain an image of the positioning posts; S32, the camera has a built-in virtual 3D coordinate, the Y axis of the virtual 3D coordinate is the linear motion direction of the camera, the X axis is perpendicular to the Y axis, the imaging image of the positioning column is placed in the virtual 3D coordinate, and punctuation is formed in the virtual 3D coordinate according to the small hole on the top surface of the positioning column; S33, the motion mechanism controlling the movement of the camera controls the camera accordingly according to the punctuation points formed in the virtual 3D coordinates.

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