Six-degree-of-freedom displacement positioning auxiliary correction method for three-dimensional vision measurement system

Abstract

The invention discloses a six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system, and relates to the technical field of three-dimensional vision measurement. The method comprises the following steps: calibrating a three-dimensional vision measurement system; a measured object is fixedly connected with the six-degree-of-freedom displacement table, and a first pose between the two coordinate systems is solved according to the coordinates of the feature points of the measured object on the world coordinate system and the coordinate system of the six-degree-of-freedom displacement table; the six-degree-of-freedom displacement platform moves a measured object and outputs six-degree-of-freedom displacement information; solving a second pose between the two coordinate systems after movement according to the coordinates of the feature points of the measured object after movement on the two coordinate systems; and determining pose change information according to the first pose and the second pose, and correcting a rotation matrix and a translation vector of the three-dimensional vision measurement system in combination with the six-degree-of-freedom displacement information. The three-dimensional vision measurement system is corrected in real time through high-precision pose output of the six-degree-of-freedom displacement table, and the precision and reliability of the three-dimensional vision measurement system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of three-dimensional vision measurement, and in particular to a six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system. Background Art

[0002] The three-dimensional vision measurement system mainly obtains the three-dimensional coordinate information of the surface of the object through the imaging technology of the camera, and can achieve high-precision measurement of the object without contact. The existing three-dimensional vision measurement system usually uses marking points or a tracking multi-level scanning system to determine the position of the feature points of the measured object. The method of using marking points is low in cost and high in precision, and is widely used, but this method requires manual pasting of marking points, which is time-consuming and not conducive to assembly line operation and large-scale measurement. The method of using a tracking multi-level scanning system mainly uses a binocular tracker to track the scanner with known structural information, and calculates the coordinate transformation matrix through the information of the fixed marking points on the scanner. This method is relatively flexible, but it has high requirements on the structural design and use process of the scanner. At the same time, due to the large size of the fixed marking point structure, the information on the inner part of the measured object cannot be measured. In addition, whether it is the method of using marking points or the method of using a tracking multi-level scanning system, the measurement process requires manual participation, and there are certain requirements on the technical level of the operator, and it is impossible to form an automated measurement field, which is not conducive to the mass promotion and application of three-dimensional vision measurement equipment. Summary of the invention

[0003] The purpose of the present invention is to provide a six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system. On the basis of the existing three-dimensional vision measurement system technology system, a high-precision six-degree-of-freedom displacement table is used as the posture reference of the object to be measured. The three-dimensional vision measurement system is corrected in real time through the high-precision posture output of the six-degree-of-freedom displacement table, which can effectively realize the rapid determination or correction of the position of the feature points of the object to be measured, and improve the accuracy and reliability of the three-dimensional vision measurement system.

[0004] In a first aspect of the present invention, a six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system is provided, the method comprising:

[0005] Calibrate the 3D vision measurement system;

[0006] The object to be measured is fixedly connected to the six-degree-of-freedom translation stage, and the coordinates of the feature points of the object to be measured in the world coordinate system are obtained based on the three-dimensional visual measurement system, and the coordinates of the feature points of the object to be measured in the six-degree-of-freedom translation stage coordinate system are obtained, and the first position between the two coordinate systems is solved according to the coordinates of the feature points of the object to be measured in the two coordinate systems, including the first rotation matrix and the first translation vector;

[0007] The six-degree-of-freedom translation stage moves the object to be measured and outputs six-degree-of-freedom displacement information, including rotation matrix components and displacement matrix components;

[0008] According to the coordinates of the feature points of the measured object in the two coordinate systems after the movement, a second posture between the two coordinate systems after the movement is solved, including a second rotation matrix and a second translation vector;

[0009] The posture change information is determined according to the first posture and the second posture, and the three-dimensional vision measurement system is corrected in combination with the six-degree-of-freedom displacement information, including: determining the rotation matrix change value of the two coordinate systems according to the first rotation matrix and the second rotation matrix, and then correcting the rotation matrix of the three-dimensional vision measurement system in combination with the rotation matrix components; determining the displacement matrix change value of the two coordinate systems according to the first translation vector and the second translation vector, and then correcting the translation vector of the three-dimensional vision measurement system in combination with the displacement matrix components.

[0010] In some embodiments, calibrating the three-dimensional vision measurement system includes:

[0011] Establish the world coordinate system Ow and the camera image coordinate system; according to the camera imaging model, the three-dimensional space point in the world coordinate system and the coordinate in the camera image coordinate system have the following relationship:

[0012]

[0013] Among them, A is the intrinsic parameter matrix of the camera, R and T are the rotation matrix and translation vector converted from the world coordinate system to the camera image coordinate system, (c x ,c y ) is the principal point of the image, (u,v) is the spatial point P(X w ,Y w ,Z w ) is projected into the camera image coordinate system, f x ,f y are the scale factors of the u-axis and v-axis, respectively, and f s is the non-perpendicular factor of the two coordinate axes, s is the spatial point P(X w ,Y w ,Z w ) is the projection along the optical axis in the camera image coordinate system; r ij is the element of the rotation matrix; t i are the elements of the translation vector.

[0014] In some embodiments, the coordinates of the feature points of the measured object in the world coordinate system are obtained based on the three-dimensional vision measurement system, and the coordinates of the feature points of the measured object in the six-degree-of-freedom translation stage coordinate system are obtained, and the first position between the two coordinate systems is solved according to the coordinates of the feature points of the measured object in the two coordinate systems, including:

[0015] Assume that the point set {P1,P2,...,P n} are all feature points on the object being measured, and their coordinates in the world coordinate system Ow are {P 1w ,P 2w ,...,P nw}; According to the imaging pixel (u, v) information of the feature point P of the measured object in the camera image coordinate system, the coordinates P (X w ,Y w ,Z w );

[0016] Assume that the point set {P1,P2,...,P n The coordinates of the six-degree-of-freedom translation platform coordinate system Os are {P 1s ,P 2s ,...,P ns}, then we have the following relationship:

[0017]

[0018] In the formula, is the first rotation matrix, is the first translation vector, and the two together constitute the first position of the six-degree-of-freedom translation platform coordinate system in the world coordinate system.

[0019] Solve the above equation by singular value decomposition method to obtain the first rotation matrix and the first translation vector The objective function is solved as follows:

[0020]

[0021] In the formula, i represents the i-th feature point on the object being measured, and n represents the total number of feature points.

[0022] In some embodiments, according to the coordinates of the feature points of the measured object in the two coordinate systems after the movement, solving the second posture between the two coordinate systems after the movement includes:

[0023] Assume that the feature point set {P1,P2,...,P n}Move to {P′1,P′2,...,P′ n}, whose coordinates in the world coordinate system Ow are {P′ 1w ,P′ 2w ,...,P′ nw}; According to the imaging pixel (u′, v′) information of the feature point P′ of the measured object in the camera image coordinate system, the coordinates P′ (X′ w,Y′ w ,Z′ w );

[0024] Assume that the point set {P′1,P′2,...,P′ n The coordinates of the six-degree-of-freedom translation platform coordinate system Os are {P′ 1s ,P′ 2s ,...,P′ ns}, then we have the following relationship:

[0025]

[0026] In the formula, is the second rotation matrix, is the second translation vector, and the two together constitute the second position of the six-degree-of-freedom translation stage coordinate system in the world coordinate system after the movement

[0027] Solve the above equation by singular value decomposition method to obtain the second rotation matrix and the second translation vector The objective function is solved as follows:

[0028]

[0029] In the formula, i represents the i-th feature point on the object being measured, and n represents the total number of feature points.

[0030] In some embodiments, the rotation matrix change values ​​of the two coordinate systems are determined according to the first rotation matrix and the second rotation matrix, and the rotation matrix of the three-dimensional vision measurement system is corrected in combination with the rotation matrix components; the displacement matrix change values ​​of the two coordinate systems are determined according to the first translation vector and the second translation vector, and the translation vector of the three-dimensional vision measurement system is corrected in combination with the displacement matrix components, including:

[0031] For the characteristic point P of the object being measured, when the six-degree-of-freedom translation platform drives it to move to point P', the following relationship should be met:

[0032]

[0033] Similarly, for the feature point set {P1,P2,...,P n} also satisfies the above relationship, namely:

[0034]

[0035] in, is the rotation matrix change value of the six-degree-of-freedom translation platform coordinate system relative to the world coordinate system, is the second rotation matrix, is the first rotation matrix; is the displacement matrix change value of the six-degree-of-freedom translation platform coordinate system relative to the world coordinate system, is the second translation vector, is the first translation vector; P(X w ,Y w ,Z w ) is the coordinate of point P in the world coordinate system, P′(X′ w ,Y′ w ,Z′ w ) is the coordinate of point P′ in the world coordinate system; the point set {P1,P2,...,P n}Move to {P′1,P′2,...,P′ n}, whose coordinates in the world coordinate system Ow are {P′ 1w ,P′ 2w ,...,P′ nw}, n represents the total number of feature points;

[0036] By minimizing the residual root mean square of the visual pose change value of the feature point set and the measured change value of the six-degree-of-freedom displacement platform, the six-degree-of-freedom displacement information ΔP is used. s Assist in correcting the positioning information of the 3D vision measurement system, namely:

[0037]

[0038] Among them, R is the rotation matrix of the 3D vision measurement system, T is the translation vector of the 3D vision measurement system, ΔP sR ΔP s The rotation matrix component, ΔP sT ΔP s The displacement matrix component of , n' is the total number of feature point sets.

[0039] In some embodiments, the method further comprises:

[0040] The coordinates of the feature points of the measured object in the world coordinate system are updated using the rotation matrix and translation vector of the calibrated 3D vision measurement system.

[0041] In some embodiments, the method further comprises:

[0042] The six-degree-of-freedom translation stage moves the object to be measured multiple times. Every time the object to be measured moves, the rotation matrix and translation vector of the three-dimensional vision measurement system are corrected once.

[0043] According to a second aspect of the present invention, a three-dimensional vision measurement system is provided, which includes the steps of the six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system as described in any one of the first aspects.

[0044] According to a third aspect of the present invention, an electronic device is provided, comprising: a processor and a memory, the memory storing programs or instructions that can be run on the processor, and when the programs or instructions are executed by the processor, the steps of the six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system described in any one of the first aspects are implemented.

[0045] According to a fourth aspect of the present invention, a readable storage medium is provided, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system described in any one of the first aspects are implemented.

[0046] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0047] The six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system proposed in the present invention, based on the existing technical system of the three-dimensional vision measurement system, uses a high-precision six-degree-of-freedom displacement table as the posture reference of the object to be measured, and corrects the three-dimensional vision measurement system in real time through the high-precision posture output of the six-degree-of-freedom displacement table, which can effectively realize the rapid determination or correction of the position of the feature points of the object to be measured, and improve the accuracy and reliability of the three-dimensional vision measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A schematic diagram of a flow chart of a six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system provided in an embodiment of the present application;

[0049] Figure 2 A schematic diagram of a six-degree-of-freedom translation platform moving a measured object provided in an embodiment of the present application;

[0050] Figure 3 A schematic diagram of the hardware structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0052] Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0053] Reference to "embodiments" in this application 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 of ordinary skill in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0054] Unless otherwise defined, the technical terms or scientific terms involved in this application should be understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation, and may represent the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships, for example, "A and / or B" can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0055] The purpose of this application is to use a high-precision six-degree-of-freedom translation stage as the position and posture reference of the object to be measured, to assist the three-dimensional vision measurement system in real-time position correction, and to improve the accuracy and reliability of the three-dimensional vision measurement system. This application can be used in a three-dimensional vision measurement system to improve the measurement accuracy of the feature points of the object to be measured; it can also be combined with a multi-eye three-dimensional vision measurement system and high-precision standard parts to form a three-dimensional vision measurement field, and through standard parts with known structural information and high-precision six-degree-of-freedom position and posture output, the measurement accuracy of the measurement field can be corrected in real time.

[0056] The embodiment of the present application provides a six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system, which is applicable to a three-dimensional vision measurement system. Figure 1 A flow chart of a six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the method comprises the following steps:

[0057] Calibrate the 3D vision measurement system;

[0058] The object to be measured is fixedly connected to the six-degree-of-freedom translation stage, and the coordinates of the feature points of the object to be measured in the world coordinate system are obtained based on the three-dimensional visual measurement system, and the coordinates of the feature points of the object to be measured in the six-degree-of-freedom translation stage coordinate system are obtained, and the first position between the two coordinate systems is solved according to the coordinates of the feature points of the object to be measured in the two coordinate systems, including the first rotation matrix and the first translation vector;

[0059] The six-degree-of-freedom translation stage moves the object to be measured and outputs six-degree-of-freedom displacement information, including rotation matrix components and displacement matrix components;

[0060] According to the coordinates of the feature points of the measured object in the two coordinate systems after the movement, a second posture between the two coordinate systems after the movement is solved, including a second rotation matrix and a second translation vector;

[0061] The posture change information is determined according to the first posture and the second posture, and the three-dimensional vision measurement system is corrected in combination with the six-degree-of-freedom displacement information, including: determining the rotation matrix change value of the two coordinate systems according to the first rotation matrix and the second rotation matrix, and then correcting the rotation matrix of the three-dimensional vision measurement system in combination with the rotation matrix components; determining the displacement matrix change value of the two coordinate systems according to the first translation vector and the second translation vector, and then correcting the translation vector of the three-dimensional vision measurement system in combination with the displacement matrix components.

[0062] Based on the existing technical system of three-dimensional vision measurement system, this application uses a high-precision six-degree-of-freedom translation table as the posture reference of the object to be measured, and corrects the three-dimensional vision measurement system in real time through the high-precision posture output of the six-degree-of-freedom translation table, which can effectively realize the rapid determination or correction of the position of the feature points of the object to be measured, and improve the accuracy and reliability of the three-dimensional vision measurement system.

[0063] Specifically, the six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system according to an embodiment of the present application includes the following steps:

[0064] Step 1: Use the calibration tool to calibrate the 3D vision measurement system and establish the world coordinate system Ow;

[0065] Step 2: Obtain the coordinates P(X) of a feature point P of the object to be measured in the world coordinate system Ow through binocular vision imaging calculation of the 3D vision measurement system. w ,Y w ,Z w );Fix the object to be measured with the six-degree-of-freedom translation platform and obtain the coordinates P(X s ,Y s ,Z s ), according to the coordinates of point P in the two coordinate systems, the position and posture of the six-degree-of-freedom translation platform coordinate system in the world coordinate system are obtained, including the rotation matrix and the translation vector;

[0066] Step 3: The six-degree-of-freedom platform moves the object to be measured, so that point P moves to point P′, and outputs the six-degree-of-freedom displacement information ΔP s ; Six degrees of freedom displacement information ΔP s Covers rotation matrix components as well as displacement matrix components;

[0067] Step 4: Obtain the coordinates P′(X′) of point P′ in the world coordinate system Ow through binocular vision imaging calculation of the 3D vision measurement system. w ,Y′ w ,Z′ w ) and the coordinates of the six-degree-of-freedom translation platform coordinate system Os. Similarly, according to the coordinates of point P′ in the two coordinate systems, the position and posture of the six-degree-of-freedom translation platform coordinate system in the world coordinate system after the six-degree-of-freedom translation platform moves are obtained;

[0068] Step 5: Use the six-degree-of-freedom displacement information to assist in correcting the positioning information of the three-dimensional vision measurement system, and obtain the rotation matrix and translation vector of the corrected three-dimensional vision measurement system. Then, the corrected rotation matrix and translation vector can be used to update the positions of P and P′, so that the positioning of the three-dimensional vision measurement system is more accurate.

[0069] In some embodiments, step S1 comprises:

[0070] The world coordinate system Ow is established for the 3D vision measurement system through specific marks on tools such as calibration plates and calibration rods. By moving the calibration plates and calibration rods and changing the position and direction of specific marks, the internal and external parameters of the camera in the 3D vision measurement can be calibrated to determine the relationship between the world coordinate system and the camera image coordinate system. According to the camera imaging model, the 3D space point in the world coordinate system and the coordinates in the camera image coordinate system have the following relationship:

[0071]

[0072] Among them, A is the intrinsic parameter matrix of the camera, R and T are the rotation matrix and translation vector (collectively referred to as extrinsic parameters) from the world coordinate system to the camera image coordinate system, and f x ,f y are the scale factors of the u-axis and v-axis, respectively, and f s is the non-perpendicular factor of the two coordinate axes, (c x ,c y ) is the principal point of the image, (u,v) is the spatial point P(X w ,Y w ,Z w ) is projected into the coordinates of the camera image coordinate system. Since the information of the marking points on the calibration plate and the calibration rod is known, the camera parameters can be obtained and the world coordinate system can be established. The object to be measured is fixedly connected to the six-degree-of-freedom translation stage, and the six-degree-of-freedom translation stage coordinate system Os is similarly connected to the world coordinate system.

[0073] In some embodiments, step S2 comprises:

[0074] Assume that the point set {P1,P2,...,P n} are all feature points on the object being measured, and their coordinates in the world coordinate system Ow are {P 1w ,P 2w ,...,P nw According to the imaging pixel (u, v) information of the feature point P of the object to be measured in the camera image coordinate system, the coordinates P (X w ,Y w ,Z w ).

[0075] The object to be measured is fixedly connected to the six-degree-of-freedom translation stage. The coordinates of point P on the six-degree-of-freedom translation stage coordinate system Os are P(X s ,Y s ,Z s ), the point set {P1,P2,...,P n The coordinates of the six-degree-of-freedom translation platform coordinate system Os are {P 1s ,P 2s ,...,P ns}. is the position of the six-degree-of-freedom translation platform coordinate system in the world coordinate system, is the rotation matrix, is the translation vector, and has the following relationship:

[0076]

[0077] By solving the above equation using the singular value decomposition method, the position and posture of the object under test can be obtained. The objective function is as follows:

[0078]

[0079] Among them, i represents the i-th feature point on the object being measured, and n represents the total number of feature points.

[0080] It should be noted that there are at least 3 feature points.

[0081] In some embodiments, step S3 includes:

[0082] like Figure 2 As shown, the six-degree-of-freedom translation stage moves the object to be measured, so that point P moves to point P′, and outputs six-degree-of-freedom displacement information ΔP s Taking the center point position of the platform on the six-degree-of-freedom translation platform as the target, the lengths of the six electric cylinders are calculated based on the inverse solution. The controller of the electric cylinder branch chain performs closed-loop control according to the command length, so that the electric cylinder is extended to the command length, the object to be measured moves to the specified position, the feature point P moves to P′, and the six-degree-of-freedom translation platform outputs the displacement information ΔP s ={δX s ,δY s ,δZ s ,δP s ,δR s ,δH s}. Among them, δX s ,δY s ,δZ s is the displacement matrix component, δP s ,δR s ,δH s are the rotation matrix components.

[0083] In some embodiments, step S4 comprises:

[0084] Assume that the point set {P1,P2,...,P n}Move to {P′1,P′2,...,P′ n}, whose coordinates in the world coordinate system Ow are {P′ 1w ,P′ 2w ,...,P′ nwAccording to the imaging pixel (u′, v′) information of the feature point P′ of the object to be measured in the camera image coordinate system, the coordinates P′ (X′ w ,Y′ w ,Z′ w ).

[0085] The object to be measured is fixedly connected to the six-degree-of-freedom translation stage. The coordinates of point P on the six-degree-of-freedom translation stage coordinate system Os are P(X s ,Y s ,Z s ), the point set {P′1,P′2,...,P′ n The coordinates of the six-degree-of-freedom translation platform coordinate system Os are {P′ 1s ,P′ 2s ,...,P′ ns}. is the position of the six-degree-of-freedom translation platform coordinate system in the world coordinate system, is the rotation matrix, is the translation vector, and has the following relationship:

[0086]

[0087] By solving the above equation using the singular value decomposition method, the position and posture of the object under test can be obtained. The objective function is as follows:

[0088]

[0089] Among them, i represents the i-th feature point on the object being measured, and n represents the total number of feature points.

[0090] In some embodiments, step S5 is used to use six-degree-of-freedom displacement information to assist in correcting the positioning information of the three-dimensional vision measurement system, including:

[0091] For the characteristic point P, after the six-degree-of-freedom translation platform drives it to move to point P', there should be the following relationship:

[0092]

[0093] Similarly, for the feature point set {P1,P2,...,P n} also satisfies the above relationship, namely:

[0094]

[0095] in, is the rotation matrix change value of the six-degree-of-freedom translation platform coordinate system relative to the world coordinate system, is the displacement matrix change value of the six-degree-of-freedom translation platform coordinate system relative to the world coordinate system,

[0096] Since the measurement accuracy of the six-degree-of-freedom displacement platform for the six-degree-of-freedom posture change is higher than that of the binocular vision measurement method, the residual root mean square of the visual posture change value of the feature point set and the measured change value of the six-degree-of-freedom displacement platform can be minimized to use the six-degree-of-freedom displacement information to assist in correcting the positioning information of the three-dimensional vision measurement system, that is:

[0097]

[0098] Among them, ΔP sR ΔP s The rotation matrix component, ΔP sT ΔP s The displacement matrix component of n' is the total number of feature point sets. By iteratively optimizing and solving the above formula, the error parameters of the 3D vision measurement system can be corrected to improve its measurement accuracy.

[0099] In order to further improve the correction accuracy, the six-degree-of-freedom translation stage can move the object to be measured multiple times. Every time the object to be measured moves, the rotation matrix and translation vector of the 3D vision measurement system are corrected once, making the result more accurate.

[0100] In addition, combined Figure 1 The six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system described in the embodiments of the present application can be implemented by a computer device. Figure 3 Schematic diagram of the hardware structure of the computer device of the embodiment of the present application. Figure 3 As shown, the device may include a processor 301 and a memory 302 storing computer program instructions.

[0101] Specifically, the processor 301 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0102] Among them, the memory 302 may include a large capacity memory for data or instructions. For example, but not limitation, the memory 302 may include a hard disk drive (HDD), a floppy disk drive, a solid state drive (SSD), a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive or a combination of two or more of these. In appropriate cases, the memory 302 may include a removable or non-removable (or fixed) medium. In appropriate cases, the memory 302 may be inside or outside the data processing device. In a specific embodiment, the memory 302 is a non-volatile memory. In a specific embodiment, the memory 302 includes a read-only memory (ROM) and a random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (Programmable Read-Only Memory, PROM for short), an erasable PROM (Erasable Programmable Read-Only Memory, EPROM for short), an electrically erasable PROM (Electrically Erasable Programmable Read-Only Memory, EEPROM for short), an electrically alterable ROM (Electrically Alterable Read-Only Memory, EAROM for short) or a flash memory (FLASH) or a combination of two or more of these. Under appropriate circumstances, the RAM can be a static random access memory (SRAM) or a dynamic random access memory (DRAM), wherein the DRAM can be a fast page mode dynamic random access memory (FPMDRAM), an extended data output dynamic random access memory (EDODRAM), a synchronous dynamic random access memory (SDRAM), etc.

[0103] The memory 302 may be used to store or cache various data files that need to be processed and / or used for communication, as well as possible computer program instructions executed by the processor 301 .

[0104] The processor 301 reads and executes computer program instructions stored in the memory 302 to implement any one of the six-degree-of-freedom displacement positioning auxiliary correction methods for a three-dimensional vision measurement system in the above embodiments.

[0105] In some embodiments, the point cloud generation device may further include a communication interface 303 and a bus 300. Figure 3 As shown, the processor 301, the memory 302, and the communication interface 303 are connected via a bus 300 and communicate with each other.

[0106] The communication interface 303 is used to implement communication between the modules, devices, units and / or equipment in the embodiment of the present application. The communication interface 303 can also implement data communication with other components such as: external devices, image / data acquisition equipment, databases, external storage, and image / data processing workstations.

[0107] The bus 300 includes hardware, software, or both, and couples the components of the point cloud generation device to each other. The bus 300 includes, but is not limited to, at least one of the following: a data bus, an address bus, a control bus, an expansion bus, and a local bus. By way of example and not limitation, bus 300 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses or a combination of two or more of the above. Bus 300 may include one or more buses, where appropriate. Although embodiments of the present application describe and illustrate a particular bus, the present application contemplates any suitable bus or interconnect.

[0108] The computer device can execute the six-degree-of-freedom displacement positioning auxiliary correction method for the three-dimensional vision measurement system in the embodiment of the present application based on the three-dimensional vision measurement system and the high-precision six-degree-of-freedom displacement stage, thereby realizing the combination Figure 1 A six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system is described.

[0109] In addition, in combination with the six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system in the above embodiment, the embodiment of the present application can provide a computer-readable storage medium for implementation. The computer-readable storage medium stores computer program instructions; when the computer program instructions are executed by a processor, any one of the six-degree-of-freedom displacement positioning auxiliary correction methods for a three-dimensional vision measurement system in the above embodiment is implemented.

[0110] It should be pointed out that the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. In addition, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0111] It is easy for a person skilled in the art to understand that the above-mentioned embodiments only express several implementation methods of the present application, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional visual measurement system, characterized in that: The method includes: Calibrate the 3D vision measurement system; The object to be measured is fixedly connected to the six-degree-of-freedom translation stage, and the coordinates of the feature points of the object to be measured in the world coordinate system are obtained based on the three-dimensional visual measurement system, and the coordinates of the feature points of the object to be measured in the six-degree-of-freedom translation stage coordinate system are obtained, and the first position between the two coordinate systems is solved according to the coordinates of the feature points of the object to be measured in the two coordinate systems, including the first rotation matrix and the first translation vector; The six-degree-of-freedom translation stage moves the object to be measured and outputs six-degree-of-freedom displacement information, including rotation matrix components and displacement matrix components; According to the coordinates of the feature points of the measured object in the two coordinate systems after the movement, a second posture between the two coordinate systems after the movement is solved, including a second rotation matrix and a second translation vector; The posture change information is determined according to the first posture and the second posture, and the three-dimensional vision measurement system is corrected in combination with the six-degree-of-freedom displacement information, including: determining the rotation matrix change value of the two coordinate systems according to the first rotation matrix and the second rotation matrix, and then correcting the rotation matrix of the three-dimensional vision measurement system in combination with the rotation matrix components; determining the displacement matrix change value of the two coordinate systems according to the first translation vector and the second translation vector, and then correcting the translation vector of the three-dimensional vision measurement system in combination with the displacement matrix components.

2. The six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system according to claim 1, characterized in that: Calibrate the 3D vision measurement system, including: Establish the world coordinate system Ow and the camera image coordinate system; according to the camera imaging model, the three-dimensional space point in the world coordinate system and the coordinate in the camera image coordinate system have the following relationship: Among them, A is the intrinsic parameter matrix of the camera, R and T are the rotation matrix and translation vector converted from the world coordinate system to the camera image coordinate system, (c x ,c y ) is the principal point of the image, (u,v) is the spatial point P(X w ,Y w ,Z w ) is projected into the camera image coordinate system, f x ,f y are the scale factors of the u-axis and v-axis, respectively, and f s is the non-perpendicular factor of the two coordinate axes, s is the spatial point P(X w ,Y w ,Z w ) is the projection along the optical axis in the camera image coordinate system; r ij is the element of the rotation matrix; t i are the elements of the translation vector.

3. The six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system according to claim 1, characterized in that: Based on the three-dimensional vision measurement system, the coordinates of the feature points of the measured object in the world coordinate system are obtained, and the coordinates of the feature points of the measured object in the six-degree-of-freedom translation stage coordinate system are obtained. According to the coordinates of the feature points of the measured object in the two coordinate systems, the first position between the two coordinate systems is solved, including: Assume that the point set {P1,P2,...,P n } are all feature points on the object being measured, and their coordinates in the world coordinate system Ow are {P 1w ,P 2w ,...,P nw }; According to the imaging pixel (u, v) information of the feature point P of the measured object in the camera image coordinate system, the coordinates P (X w ,Y w ,Z w ); Assume that the point set {P1,P2,...,P n The coordinates of the six-degree-of-freedom translation platform coordinate system Os are {P 1s ,P 2s ,...,P ns }, then we have the following relationship: In the formula, is the first rotation matrix, is the first translation vector, and the two together constitute the first position of the six-degree-of-freedom translation platform coordinate system in the world coordinate system. Solve the above equation by singular value decomposition method to obtain the first rotation matrix and the first translation vector The objective function is solved as follows: In the formula, i represents the i-th feature point on the object being measured, and n represents the total number of feature points.

4. The six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system according to claim 1, characterized in that: According to the coordinates of the feature points of the measured object in the two coordinate systems after the movement, the second posture between the two coordinate systems after the movement is solved, including: Assume that the feature point set {P1,P2,...,P n }Move to {P1′,P2′,...,P n ′}, its coordinates in the world coordinate system Ow are {P1′ w ,P2′ w ,...,P n ' w }; According to the imaging pixel (u′, v′) information of the feature point P′ of the measured object in the camera image coordinate system, the coordinates P′ (X′ w ,Y w ′,Z′ w ); Assume that the point set {P1′,P2′,...,P n The coordinates of P1′ on the six-degree-of-freedom translation platform coordinate system Os are respectively s ,P2′ s ,...,P n ' s }, then we have the following relationship: In the formula, is the second rotation matrix, is the second translation vector, and the two together constitute the second position of the six-degree-of-freedom translation stage coordinate system in the world coordinate system after the movement Solve the above equation by singular value decomposition method to obtain the second rotation matrix and the second translation vector The objective function is solved as follows: In the formula, i represents the i-th feature point on the object being measured, and n represents the total number of feature points.

5. The six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system according to claim 1, characterized in that: Determine the rotation matrix change values ​​of the two coordinate systems according to the first rotation matrix and the second rotation matrix, and then correct the rotation matrix of the three-dimensional vision measurement system in combination with the rotation matrix components; Determine the displacement matrix change value of the two coordinate systems according to the first translation vector and the second translation vector, and then correct the translation vector of the three-dimensional vision measurement system in combination with the displacement matrix components, including: For the characteristic point P of the object being measured, when the six-degree-of-freedom translation platform drives it to move to point P', the following relationship should be met: Similarly, for the feature point set {P1,P2,...,P n } also satisfies the above relationship, namely: Among them, Δ s w R is the rotation matrix change value of the six-degree-of-freedom translation stage coordinate system relative to the world coordinate system, is the second rotation matrix, is the first rotation matrix; is the displacement matrix change value of the six-degree-of-freedom translation platform coordinate system relative to the world coordinate system, is the second translation vector, is the first translation vector; P(X w ,Y w ,Z w ) is the coordinate of point P in the world coordinate system, P′(X′ w ,Y w ′,Z′ w ) is the coordinate of point P′ in the world coordinate system; the point set {P1,P2,...,P n }Move to {P1′,P2′,...,P n ′}, its coordinates in the world coordinate system Ow are {P1′ w ,P2′ w ,...,P n ' w }, n represents the total number of feature points; By minimizing the residual root mean square of the visual pose change value of the feature point set and the measured change value of the six-degree-of-freedom displacement platform, the six-degree-of-freedom displacement information ΔP is used. s Assist in correcting the positioning information of the 3D vision measurement system, namely: Among them, R is the rotation matrix of the 3D vision measurement system, T is the translation vector of the 3D vision measurement system, ΔP sR ΔP s The rotation matrix component, ΔP sT ΔP s The displacement matrix component of , n' is the total number of feature point sets.

6. The six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system according to claim 1, characterized in that: The method further includes: The coordinates of the feature points of the measured object in the world coordinate system are updated using the rotation matrix and translation vector of the calibrated 3D vision measurement system.

7. The six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system according to claim 1, characterized in that: The method further includes: The six-degree-of-freedom translation stage moves the object to be measured multiple times. Every time the object to be measured moves, the rotation matrix and translation vector of the three-dimensional vision measurement system are corrected once.

8. A three-dimensional visual measurement system, characterized in that: The three-dimensional vision measurement system includes the steps of the six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system as described in any one of claims 1 to 7.

9. An electronic device, characterized in that: include: A processor and a memory, wherein the memory stores programs or instructions that can be run on the processor, and when the programs or instructions are executed by the processor, the steps of the six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system described in any one of claims 1 to 7 are implemented.

10. A readable storage medium, characterized in that: A program or instruction is stored thereon, and when the program or instruction is executed by a processor, the steps of the six-degree-of-freedom displacement positioning auxiliary correction method for a three-dimensional vision measurement system as described in any one of claims 1 to 7 are implemented.

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