Multi-surface three-dimensional target calibration method, system, equipment and medium

Abstract

The invention discloses a multi-surface three-dimensional target calibration method, system and device and a medium, and relates to the technical field of computer vision and precision measurement. The method comprises the following steps: determining a first target point coordinate when a first group of target points of a three-dimensional target face a measuring machine based on a target point position relation calibration method; using a three-coordinate measuring machine to measure a first target position when a first group of target points of the three-dimensional target face the measuring machine; determining a second target point coordinate when a second group of target points of the three-dimensional target face the measuring machine based on a target point position relation calibration method; using the three-coordinate measuring machine to measure a second target position when a second group of target points of the three-dimensional target face the measuring machine; determining a coordinate transformation equation according to the target position; and calculating a third target point coordinate when the first group of target points of the three-dimensional target face the measuring machine according to the coordinate transformation equation and the second target point coordinate, and further determining a final calibration result of the three-dimensional target. According to the invention, high-precision calibration of the multi-surface three-dimensional target can be realized.

Description

Technical Field

[0001] The present invention relates to the technical fields of computer vision and precision measurement, and particularly relates to a calibration method, system, device and medium for a multi-faceted three-dimensional target. Background Art

[0002] With the rapid development of supporting disciplines such as industrial automation, artificial intelligence, robotics, and hardware devices, computer vision technology has increasingly shown its important position in interdisciplinary fields. As a high-end technology that combines computer vision and precision measurement, vision measurement technology has been widely applied in fields such as electronics, automotive, metallurgy, food and beverage, parts and equipment, and manufacturing. Among them, multi-faceted three-dimensional targets play an important role in camera calibration and the selection of measurement schemes. Currently, the calibration of multi-faceted three-dimensional targets is mainly divided into two types. One is to directly use the target after processing according to a fixed size, and the accuracy of the target is mainly guaranteed by the processing accuracy. This method does not require calibration, but the position accuracy of the target is low. The other is to decompose the multi-faceted three-dimensional target into multiple groups of targets, calibrate each group of targets separately, and then splice the complete multi-faceted three-dimensional target through methods such as stereo matching. The accuracy of the target is mainly guaranteed by the splicing algorithm. However, the method of stereo matching has limited accuracy and limited applicable scenarios, and cannot meet the requirements of some high-precision measurement systems for target accuracy.

[0003] In summary, the existing technology mainly performs splicing based on the results of visual calibration using the method of stereo matching. The accuracy of splicing is equivalent to the calibration accuracy and cannot be further improved. At the same time, it is only applicable to three-dimensional targets with common target points under different perspectives, otherwise stereo matching cannot be performed. Summary of the Invention

[0004] The purpose of the present invention is to provide a calibration method, system, device and medium for a multi-faceted three-dimensional target to achieve high-precision calibration of the multi-faceted three-dimensional target.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] A calibration method for a multi-faceted three-dimensional target, comprising:

[0007] Determining the first set of target coordinates when the first set of target points of the three-dimensional target face the measuring machine based on the target point position relationship calibration method as the first target coordinates;

[0008] Measuring the position of the three-dimensional target when the first set of target points face the measuring machine using a coordinate measuring machine as the first target position;

[0009] Determining the second set of target coordinates when the second set of target points of the three-dimensional target face the measuring machine based on the target point position relationship calibration method as the second target coordinates;

[0010] Use a three - coordinate measuring machine to measure the position of the three - dimensional target when the second group of target points face the measuring machine, and use it as the second target position;

[0011] Determine a coordinate transformation equation based on the first target position and the second target position;

[0012] Calculate the coordinates of the second group of target points of the three - dimensional target when the first group of target points face the measuring machine according to the coordinate transformation equation and the coordinates of the second target points, and use it as the coordinates of the third target points;

[0013] Determine the first target point coordinates and the third target point coordinates as the final calibration result of the three - dimensional target.

[0014] Optionally, determine the coordinates of the first group of target points of the three - dimensional target when the first group of target points face the measuring machine based on the target - point position relationship calibration method, and use it as the first target point coordinates. Specifically, it includes:

[0015] When calibrating the first group of target points of the three - dimensional target facing the measuring machine using the target - point position relationship calibration method, use the coordinates of the first group of target points in the auxiliary target coordinate system as the first auxiliary coordinates;

[0016] According to the fixed position deviation between the auxiliary target coordinate system and the measuring machine coordinate system, convert the first auxiliary coordinates into the first target point coordinates; the first target point coordinates are the coordinates of the first group of target points of the three - dimensional target in the measuring machine coordinate system when the first group of target points face the measuring machine.

[0017] Optionally, determine the coordinates of the second group of target points of the three - dimensional target when the second group of target points face the measuring machine based on the target - point position relationship calibration method, and use it as the second target point coordinates. Specifically, it includes:

[0018] When calibrating the second group of target points of the three - dimensional target facing the measuring machine using the target - point position relationship calibration method, use the coordinates of the second group of target points in the auxiliary target coordinate system as the second auxiliary coordinates;

[0019] According to the fixed position deviation between the auxiliary target coordinate system and the measuring machine coordinate system, convert the second auxiliary coordinates into the second target point coordinates; the second target point coordinates are the coordinates of the second group of target points of the three - dimensional target in the measuring machine coordinate system when the second group of target points face the measuring machine.

[0020] Optionally, determine the coordinate transformation equation according to the first target position and the second target position. Specifically, it includes:

[0021] Calculate the rotation matrix and translation matrix for the transformation of the three - dimensional target coordinate system to the measuring machine coordinate system according to the first target position, and use it as the first transformation matrix information;

[0022] Calculate the rotation matrix and translation matrix for transforming the stereo target coordinate system to the measuring machine coordinate system based on the second target position, and use them as the second transformation matrix information;

[0023] Determine the coordinate transformation equation based on the first transformation matrix information and the second transformation matrix information.

[0024] Optionally, the expression of the coordinate transformation equation is:

[0025]

[0026] where, P n is the coordinate of the target point of the first group of target points of the stereo target facing the measuring machine in the measuring machine coordinate system, P m is the coordinate of the target point of the second group of target points of the stereo target facing the measuring machine in the measuring machine coordinate system, R1 is the rotation matrix in the first transformation matrix information, T1 is the translation matrix in the first transformation matrix information, R2 is the rotation matrix in the second transformation matrix information, and T2 is the translation matrix in the second transformation matrix information.

[0027] Optionally, the expression of the third target point coordinate is:

[0028]

[0029] where, P c3 is the third target point coordinate, P a2 +T c is the second target point coordinate, P a2 is the second auxiliary coordinate, and T c is the fixed position deviation between the auxiliary target coordinate system and the measuring machine coordinate system.

[0030] Optionally, the first group of target points and the second group of target points are not coplanar.

[0031] A multi-faceted stereo target calibration system, comprising:

[0032] A first calibration module, configured to determine the first group of target point coordinates of the stereo target when the first group of target points face the measuring machine based on the target point position relationship calibration method, and use them as the first target point coordinates;

[0033] A first measurement module, configured to measure the position of the stereo target when the first group of target points of the stereo target face the measuring machine by using a coordinate measuring machine, and use it as the first target position;

[0034] A second calibration module, configured to determine the second group of target point coordinates of the stereo target when the second group of target points face the measuring machine based on the target point position relationship calibration method, and use them as the second target point coordinates;

[0035] A second measurement module, configured to measure the position of the three-dimensional target when the second group of target points of the three-dimensional target face the measuring machine by using a coordinate measuring machine, as the second target position;

[0036] An equation determination module, configured to determine a coordinate transformation equation according to the first target position and the second target position;

[0037] A coordinate transformation module, configured to calculate the coordinates of the second group of target points when the first group of target points of the three-dimensional target face the measuring machine according to the coordinate transformation equation and the coordinates of the second target points, as the coordinates of the third target points;

[0038] A result determination module, configured to determine the first target point coordinates and the third target point coordinates as the final calibration result of the three-dimensional target.

[0039] An electronic device, including a memory and a processor, where the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the above multi-faceted three-dimensional target calibration method.

[0040] A computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the above multi-faceted three-dimensional target calibration method is implemented.

[0041] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0042] The multi-faceted three-dimensional target calibration method provided by the present invention determines the coordinate transformation equation for the transformation of target point coordinates in two different orientations by respectively calibrating and measuring the target point coordinates and target position when two groups of target points of the three-dimensional target face the measuring machine, and calculates the coordinates of the second group of target points when the first group of target points of the three-dimensional target face the measuring machine according to this equation, so as to obtain the first group of target point coordinates and the second group of target point coordinates when the first group of target points of the three-dimensional target face the measuring machine as the final calibration result. Compared with the prior art, the present invention improves the calibration accuracy of the multi-faceted three-dimensional target, and at the same time solves the problem of calibrating three-dimensional targets that cannot be calibrated using the stereo matching method, and has a wider application range. Description of the Drawings

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings without creative efforts based on these drawings.

[0044] Figure 1 It is a flowchart of the multi-faceted three-dimensional target calibration method provided by the present invention;

[0045] Figure 2 The specific flowchart of the multi-faceted three-dimensional target calibration method provided by the present invention;

[0046] Figure 3 The schematic diagram of the multi-faceted three-dimensional target provided by the present invention. Specific embodiments

[0047] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] The purpose of the present invention is to provide a multi-faceted three-dimensional target calibration method, system, device and medium to achieve high-precision calibration of the multi-faceted three-dimensional target.

[0049] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] The present invention provides a multi-faceted three-dimensional target calibration method, which uses a coordinate measuring machine (CMM) with an accuracy of 0.001 mm to calibrate a three-dimensional target having at least two sets of target points (i.e., target lights). Among them, the first set of target points and the second set of target points of the three-dimensional target are not coplanar. Taking Figure 3 the shown three-dimensional target as an example, the coordinates of the first set of target points are located on the front of the three-dimensional target. Refer to the left half in Figure 3 , and the coordinates of the second set of target points are located on the back of the three-dimensional target. Refer to the right half in Figure 3 . As shown in Figure 1 and Figure 2 , the method includes:

[0051] Step S1: Based on the target point position relationship calibration method, determine the coordinates of the first set of target points of the three-dimensional target when the first set of target points S1 faces the measuring machine, as the first target coordinates.

[0052] This step specifically includes: using the target point position relationship calibration method to calibrate the coordinates of the first set of target points of the three-dimensional target in the auxiliary target coordinate system when the first set of target points face the measuring machine, as the first auxiliary coordinates P a1 ; according to the fixed position deviation T c between the auxiliary target coordinate system and the measuring machine coordinate system, convert the first auxiliary coordinates into the first target coordinates P c1; The first target coordinates are the coordinates of the first group of targets of the stereo target in the coordinate system of the measuring machine when the first group of targets face the measuring machine. The conversion formula for the first target coordinates is as follows:

[0053] P c1＝ P a1 +T c

[0054] In this embodiment, the stereo target is fixed on the workbench so that S1 faces the measuring machine, denoted as position 1.

[0055] In addition, the method for calibrating the target position relationship adopts the method in the paper "Yang Bowen. Research on Key Technologies of Visual Detection of Assembly Pose of Large Equipment [D]. Nanjing University of Aeronautics and Astronautics, 2013.", which will not be elaborated here.

[0056] Step S2: Use a coordinate measuring machine to measure the position of the stereo target when the first group of targets of the stereo target face the measuring machine, as the first target position.

[0057] In this embodiment, use a coordinate measuring machine to construct the coordinate system of the stereo target, measure the position of the stereo target when the first group of targets of the stereo target face the measuring machine, as the first target position, and combine the first target coordinates P c1 calculated in step S1 to determine the rotation matrix R1 and translation matrix T1 from the coordinate system of the stereo target to the coordinate system of the measuring machine.

[0058] Step S3: Based on the method for calibrating the target position relationship, determine the coordinates of the second group of targets of the stereo target when the second group of targets face the measuring machine, as the second target coordinates.

[0059] This step specifically includes: using the method for calibrating the target position relationship to calibrate the coordinates of the second group of targets of the stereo target in the coordinate system of the auxiliary target when the second group of targets face the measuring machine, as the second auxiliary coordinates P a2 ; According to the fixed position deviation T c between the coordinate system of the auxiliary target and the coordinate system of the measuring machine, convert the second auxiliary coordinates into the second target coordinates P c2 ; The second target coordinates are the coordinates of the second group of targets of the stereo target in the coordinate system of the measuring machine when the second group of targets face the measuring machine. The conversion formula for the second target coordinates is as follows:

[0060] P c2＝ P a2 +T c

[0061] In this embodiment, the stereo target is fixed on the workbench so that S2 faces the camera, denoted as position 2.

[0062] Step S4: Use a coordinate measuring machine to measure the position of the three-dimensional target when the second group of target points face the measuring machine, and take it as the second target position.

[0063] In this embodiment, a coordinate measuring machine is used to construct the coordinate system of the three-dimensional target, and the position of the three-dimensional target when the second group of target points face the measuring machine is measured as the second target position. Combining with the second target point coordinates P c2 calculated in step S3, the rotation matrix R2 and translation matrix T2 from the three-dimensional target coordinate system to the measuring machine coordinate system can be determined.

[0064] Step S5: Determine the coordinate transformation equation according to the first target position and the second target position.

[0065] This step specifically includes: calculating the rotation matrix and translation matrix for transforming the three-dimensional target coordinate system to the measuring machine coordinate system according to the first target position as the first transformation matrix information; calculating the rotation matrix and translation matrix for transforming the three-dimensional target coordinate system to the measuring machine coordinate system according to the second target position as the second transformation matrix information; and determining the coordinate transformation equation according to the first transformation matrix information and the second transformation matrix information.

[0066] According to the relationship between the three-dimensional target coordinate system and the coordinate measuring machine coordinate system (i.e., the measuring machine coordinate system) obtained from the above steps, the coordinate transformation equation for the three-dimensional target to transform from position 2 to position 1 is:

[0067]

[0068] where P n is the coordinate of the target point of the first group of target points of the three-dimensional target facing the measuring machine (i.e., position 1) in the measuring machine coordinate system, P m is the coordinate of the target point of the second group of target points of the three-dimensional target facing the measuring machine (i.e., position 2) in the measuring machine coordinate system, R1 is the rotation matrix in the first transformation matrix information, T1 is the translation matrix in the first transformation matrix information, R2 is the rotation matrix in the second transformation matrix information, and T2 is the translation matrix in the second transformation matrix information.

[0069] Step S6: Calculate the coordinates of the second group of target points of the three-dimensional target when the first group of target points face the measuring machine according to the coordinate transformation equation and the second target point coordinates, and take it as the third target point coordinates. The calculation formula for the third target point coordinates is as follows:

[0070]

[0071] where P c3 is the third target point coordinates, P a2 +T c is the second target point coordinates, P a2is the second auxiliary coordinate, T c is the fixed position deviation between the auxiliary target coordinate system and the coordinate system of the measuring machine.

[0072] Step S7: Determine the first target point coordinate and the third target point coordinate as the final calibration result of the three-dimensional target.

[0073] In summary, the present invention provides a calibration method for a multi-sided three-dimensional target, which further improves the calibration accuracy of the three-dimensional target and solves the calibration problem of the three-dimensional target that cannot be calibrated using the three-dimensional matching method.

[0074] To execute the above method to achieve the corresponding functions and technical effects, a calibration system for a multi-sided three-dimensional target is provided below. The system includes:

[0075] The first calibration module is used to determine the first set of target point coordinates when the first set of target points of the three-dimensional target face the measuring machine based on the target point position relationship calibration method, as the first target point coordinates.

[0076] The first measurement module is used to measure the position of the three-dimensional target when the first set of target points of the three-dimensional target face the measuring machine using a coordinate measuring machine, as the first target position.

[0077] The second calibration module is used to determine the second set of target point coordinates when the second set of target points of the three-dimensional target face the measuring machine based on the target point position relationship calibration method, as the second target point coordinates.

[0078] The second measurement module is used to measure the position of the three-dimensional target when the second set of target points of the three-dimensional target face the measuring machine using a coordinate measuring machine, as the second target position.

[0079] The equation determination module is used to determine the coordinate transformation equation according to the first target position and the second target position.

[0080] The coordinate transformation module is used to calculate the second set of target point coordinates when the first set of target points of the three-dimensional target face the measuring machine according to the coordinate transformation equation and the second target point coordinates, as the third target point coordinates.

[0081] The result determination module is used to determine the first target point coordinate and the third target point coordinate as the final calibration result of the three-dimensional target.

[0082] The present invention also provides an electronic device, including a memory and a processor. The memory is used to store a computer program, and the processor is used to run the computer program so that the electronic device executes the above-mentioned calibration method for a multi-sided three-dimensional target. The electronic device can be a server.

[0083] In addition, the present invention also provides a computer-readable storage medium storing a computer program, which when executed by a processor implements the above-described multi-faceted three-dimensional target calibration method.

[0084] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. For the system disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0085] Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method of the present invention and its core idea. At the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation on the present invention.

Claims

1. A calibration method for a multi-faceted three-dimensional target, characterized in that, Including: Determining a first set of target point coordinates when the first set of target points of the stereo target are oriented towards the measuring machine based on the target point position relationship calibration method, and using them as the first target point coordinates; Measuring the position of the stereo target when the first set of target points of the stereo target are oriented towards the measuring machine using a coordinate measuring machine, and using it as the first target position; Determining a second set of target point coordinates when the second set of target points of the stereo target are oriented towards the measuring machine based on the target point position relationship calibration method, and using them as the second target point coordinates; Measuring the position of the stereo target when the second set of target points of the stereo target are oriented towards the measuring machine using a coordinate measuring machine, and using it as the second target position; Determining a coordinate transformation equation based on the first target position and the second target position; Calculating the second set of target point coordinates when the first set of target points of the stereo target are oriented towards the measuring machine based on the coordinate transformation equation and the second target point coordinates, and using them as the third target point coordinates; Determining the first target point coordinates and the third target point coordinates as the final calibration result of the stereo target.

2. The multi-faceted three-dimensional target calibration method according to claim 1, wherein, Determining a first set of target point coordinates when the first set of target points of the stereo target are oriented towards the measuring machine based on the target point position relationship calibration method, and using them as the first target point coordinates, specifically including: Calibrating the coordinates of the first set of target points in the auxiliary target coordinate system when the first set of target points of the stereo target are oriented towards the measuring machine using the target point position relationship calibration method, and using them as the first auxiliary coordinates; Converting the first auxiliary coordinates into the first target point coordinates according to the fixed position deviation between the auxiliary target coordinate system and the measuring machine coordinate system; the first target point coordinates are the coordinates of the first set of target points in the measuring machine coordinate system when the first set of target points of the stereo target are oriented towards the measuring machine.

3. The multi-faceted three-dimensional target calibration method according to claim 2, characterized in that, Determining a second set of target point coordinates when the second set of target points of the stereo target are oriented towards the measuring machine based on the target point position relationship calibration method, and using them as the second target point coordinates, specifically including: Calibrating the coordinates of the second set of target points in the auxiliary target coordinate system when the second set of target points of the stereo target are oriented towards the measuring machine using the target point position relationship calibration method, and using them as the second auxiliary coordinates; Converting the second auxiliary coordinates into the second target point coordinates according to the fixed position deviation between the auxiliary target coordinate system and the measuring machine coordinate system; the second target point coordinates are the coordinates of the second set of target points in the measuring machine coordinate system when the second set of target points of the stereo target are oriented towards the measuring machine.

4. The multi-faceted three-dimensional target calibration method according to claim 3, characterized in that Determining a coordinate transformation equation based on the first target position and the second target position, specifically including: Calculating the rotation matrix and translation matrix for transforming the stereo target coordinate system to the measuring machine coordinate system based on the first target position, and using them as the first transformation matrix information; Calculating the rotation matrix and translation matrix for transforming the stereo target coordinate system to the measuring machine coordinate system based on the second target position, and using them as the second transformation matrix information; Determining a coordinate transformation equation based on the first transformation matrix information and the second transformation matrix information.

5. The multi-faceted three-dimensional target calibration method according to claim 4, wherein The expression of the coordinate transformation equation is: Among them, P n is the coordinate of the target point of the first group of target points of the three-dimensional target towards the measuring machine in the coordinate system of the measuring machine. P m is the coordinate of the target point of the second group of target points of the three-dimensional target towards the measuring machine in the coordinate system of the measuring machine. R1 is the rotation matrix in the first transformation matrix information, T1 is the translation matrix in the first transformation matrix information, R2 is the rotation matrix in the second transformation matrix information, and T2 is the translation matrix in the second transformation matrix information.

6. The multi-faceted three-dimensional target calibration method according to claim 5, characterized in that, The expression of the third target point coordinates is: Among them, P c3 is the third target coordinate, P a2 +T c is the second target coordinate, P a2 is the second auxiliary coordinate, and T c is the fixed position deviation between the auxiliary target coordinate system and the measuring machine coordinate system.

7. The multi-faceted three-dimensional target calibration method according to claim 1, characterized in that The first set of target points and the second set of target points are not coplanar.

8. A multi-faceted three-dimensional target calibration system, characterized in that, Including: A first calibration module for determining a first set of target point coordinates when the first set of target points of the stereo target are oriented towards the measuring machine based on the target point position relationship calibration method, and using them as the first target point coordinates; A first measurement module, configured to measure the position of the three-dimensional target when the first group of target points of the three-dimensional target face the measuring machine by using a coordinate measuring machine, as the first target position; A second calibration module, configured to determine the coordinates of the second group of target points when the second group of target points of the three-dimensional target face the measuring machine based on a target point position relationship calibration method, as the second target coordinates; A second measurement module, configured to measure the position of the three-dimensional target when the second group of target points of the three-dimensional target face the measuring machine by using a coordinate measuring machine, as the second target position; An equation determination module, configured to determine a coordinate transformation equation according to the first target position and the second target position; A coordinate transformation module, configured to calculate the coordinates of the second group of target points when the first group of target points of the three-dimensional target face the measuring machine according to the coordinate transformation equation and the second target coordinates, as the third target coordinates; A result determination module, configured to determine the first target coordinates and the third target coordinates as the final calibration result of the three-dimensional target.

9. An electronic device, characterized in that, It includes a memory and a processor, the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the multi-faceted three-dimensional target calibration method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, It stores a computer program, and when the computer program is executed by the processor, it implements the multi-faceted three-dimensional target calibration method according to any one of claims 1 to 7.

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