Three-dimensional reconstruction method based on linear structure light spot set monomer kinematics calibration

Abstract

The invention discloses a three-dimensional reconstruction method based on linear structure light spot set monomer kinematics calibration, and the method comprises the steps: enabling an area-array camera and a linear structure light emitter to be rigidly combined, and enabling the area-array camera and the linear structure light emitter to be installed on a motion platform; calibrating structural parameters of a motion platform of the measuring device by using the radius standard value of the standard ball and the linear structured light scanning data; calibrating the spatial position relation of the line scanning point set by taking the calibrated center position of the standard ball and the standard radius of the standard ball as constraints; controlling the five-axis motion platform to move and acquiring scanning data of the measured piece under different poses; and the scanning data and the real-time point cloud calibration matrix are utilized to complete the multi-pose scanning high-quality three-dimensional model reconstruction of the measured piece. The system comprises a device fixing module, a calibration module, a point cloud calibration module, a scanning module and a point cloud reconstruction module. According to the invention, the reconstruction precision of the line structured light three-dimensional point cloud model can be improved. The method can be widely applied to the field of three-dimensional reconstruction.

Description

Technical Field

[0001] The present invention relates to the field of three-dimensional reconstruction, and in particular to a three-dimensional reconstruction method based on monomerized kinematic calibration of a line structured light point set. Background Art

[0002] With the rapid development of my country's manufacturing industry, the requirements for high-precision inspection of complex workpieces are increasing. The combination of line structured light and a five-axis motion platform can achieve multi-pose scanning and point cloud model reconstruction, thereby completing the inspection task of complex workpieces. However, due to manufacturing and assembly errors, there is often a certain deviation between the actual structure and the theoretical structure of the five-axis motion platform, which affects its positioning accuracy. Since the reconstruction accuracy of line structured light is related to the platform structure, the platform accuracy is first improved through kinematic calibration, and then the point cloud is obtained through line structured light scanning, and the point cloud is calibrated in real time, which can improve the three-dimensional reconstruction accuracy of the line structured light multi-pose scanning system.

[0003] Kinematic calibration is a method used to compensate for the geometric errors of the platform and improve its absolute accuracy. Existing kinematic calibration methods usually rely on expensive equipment such as laser trackers to collect multi-axis motion posture information, which has high calibration costs and insufficient observation data. In addition, the accuracy of line structured light multi-pose 3D reconstruction is not only related to the positioning accuracy of the platform, but also affected by the position accuracy of the point cloud. Existing methods usually do not consider the real-time calibration of the point cloud measured by the line structured light, resulting in insufficient 3D reconstruction accuracy of the line structured light multi-pose scanning system. Summary of the invention

[0004] In view of this, in order to solve the three-dimensional reconstruction problem of the existing line structured light multi-pose scanning system, the present invention proposes a three-dimensional reconstruction method based on the individual kinematic calibration of the line structured light point set, and the method comprises the following steps:

[0005] The area array camera and the one-line structured light emitter are rigidly combined and mounted on a five-axis motion platform to obtain a measuring device;

[0006] Using the standard value of the standard sphere radius and the line structured light scanning data, calibrate the structural parameters of the motion platform of the measuring device to obtain a calibrated measuring device;

[0007] Taking the calibrated center position of the standard sphere and the standard radius of the standard sphere as constraints, the spatial position relationship of the line scan point set is calibrated to obtain the instant point cloud calibration matrix;

[0008] Controlling the movement of the five-axis motion platform and acquiring scanning data of the standard ball at different positions and postures;

[0009] Based on the calibrated measuring device, high-quality three-dimensional model reconstruction of the multi-pose scanning of the measured object is automatically completed according to the scanning data and the real-time point cloud calibration matrix.

[0010] The beneficial effects of this embodiment are: non-contact three-dimensional visual measurement is achieved by combining a straight-line structured light emitter and a camera, without the need for a laser tracker, thereby reducing calibration costs; and, since the line structured light three-dimensional scanning system can collect dense point clouds by controlling the movement of the platform, all point clouds can directly participate in the calibration of the structural parameters of the motion platform, the amount of observation data required for calibration is greatly increased, thereby improving the recognition accuracy of error parameters.

[0011] Furthermore, if the measuring device has already been calibrated, the calibration step is skipped.

[0012] In some embodiments, the step of calibrating the structural parameters of the motion platform of the measuring device using the standard value of the standard sphere radius and the line structured light scanning data to obtain the calibrated measuring device specifically includes:

[0013] Fix the standard ball at the center of the flange at the end of the five-axis motion platform;

[0014] Controlling the movement of the five-axis motion platform and acquiring scanning data of the standard ball in different positions and postures;

[0015] According to the influence of each axis of the five-axis motion platform on the end, the kinematic model and kinematic error model are constructed, and the error parameter items are determined;

[0016] Solve the spherical arc point cloud in the terminal coordinate system and take multiple frames of point cloud to fit the sphere center to obtain the initial sphere center position;

[0017] Constructing an objective function based on the three-dimensional information of the spherical arc point cloud, the initial sphere center position and the standard radius of the standard sphere;

[0018] Based on the objective function, all the spherical arc point sets are monomerized and directly involved in error identification, so as to complete the calibration of the motion platform structure parameters and obtain the calibrated measuring device.

[0019] The beneficial effect of this embodiment is that the influence of the structural parameters of each motion platform of the translation axis and the rotation axis on the measurement of the center and the measurement radius of the standard sphere is utilized, so as to minimize the interference caused by the error of the line structured light plane solution, and the calibration of the translation axis and the rotation axis can be taken into account. At the same time, all the spherical arc point sets obtained by scanning can be directly involved in the error identification after being monomerized, and finally the error parameter item identification result is ensured to be accurate, thereby improving the platform motion accuracy and the reconstruction accuracy of the three-dimensional point cloud model.

[0020] In some embodiments, the step of completing high-quality three-dimensional model reconstruction of the multi-pose scan of the measured object based on the calibrated measuring device using the scanning data and the real-time point cloud calibration matrix specifically includes:

[0021] Based on the calibrated measuring device, according to the camera intrinsic parameter matrix and the light plane equation in the camera coordinate system, the three-dimensional information of the center point of the line structured light stripe in the camera coordinate system is solved;

[0022] The scan data at each posture is converted to the end coordinate system by combining the hand-eye transformation matrix, the calibrated inverse kinematic transformation matrix and the real-time point cloud calibration matrix.

[0023] The beneficial effect of this embodiment is that the calibration of the spatial position relationship of the line scanning point set can be realized by using the center position of the standard ball after kinematic calibration, so that the detection accuracy of the system is further improved. The line structured light system is combined with the multi-axis motion platform after kinematic calibration to perform multi-directional scanning of complex workpieces and convert each frame point cloud to the same coordinate system through the motion relationship, automatically realizing high-quality and complete morphology reconstruction of the multi-directional scanning point cloud model of complex workpieces.

[0024] The present invention also proposes a three-dimensional reconstruction system, the system comprising:

[0025] A device fixing module is used to rigidly combine the area array camera and the one-line structured light emitter, and install them on a five-axis motion platform to obtain a measuring device;

[0026] A calibration module, using a standard value of a standard sphere radius and line structured light scanning data to calibrate the structural parameters of the motion platform of the measuring device to obtain a calibrated measuring device;

[0027] The point cloud calibration module uses the calibrated center position of the standard sphere and the standard radius of the standard sphere as constraints to calibrate the spatial position relationship of the line scan point set and obtain the instant point cloud calibration matrix;

[0028] A scanning module, used to control the movement of the five-axis motion platform and obtain scanning data of the measured object in different positions and postures;

[0029] The point cloud reconstruction module automatically completes high-quality three-dimensional model reconstruction of the multi-pose scanning of the measured object based on the calibrated measuring device and the scanning data and the real-time point cloud calibration matrix.

[0030] Based on the above scheme, the present invention provides a three-dimensional reconstruction method based on the monomer kinematic calibration of line structured light point sets, which combines line structured light with a five-axis platform, and uses the calibrated five-axis platform and the three-dimensional point cloud to perform three-dimensional reconstruction of the overall morphology of the workpiece under test. While ensuring the motion accuracy of the platform and the absolute accuracy of the line scanning point set, the reconstruction accuracy of the line structured light multi-pose three-dimensional point cloud model is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of the steps of a three-dimensional reconstruction method based on the individual kinematic calibration of a line structure light point set of the present invention;

[0032] Figure 2 is a schematic diagram of kinematic modeling of a five-axis motion platform according to a specific embodiment of the present invention;

[0033] Figure 3 is a schematic diagram of light plane solution deviation in a specific embodiment of the present invention;

[0034] Figure 4 It is a structural block diagram of a three-dimensional reconstruction system of the present invention. DETAILED DESCRIPTION

[0035] In addition to the fact that the existing calibration methods in the background technology usually need to rely on expensive equipment such as laser trackers, which leads to high costs, the traditional standard sphere calibration method uses the center of the sphere solved by each point cloud to calibrate the kinematic parameters. There are fewer parameters that can be involved in the identification, and it is impossible to calibrate multiple motion platform structural parameters at the same time. At the same time, since the center of the sphere solution of a single point cloud is easily affected and disturbed by the accuracy of the stripe center point solution, it is difficult to ensure the accuracy of the identification result, which in turn affects the platform positioning accuracy and the point cloud model reconstruction accuracy.

[0036] 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.

[0037] It should be noted that, for the convenience of description, only the parts related to the relevant invention are shown in the drawings. In the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

[0038] It should be understood that the "system", "device" and / or "module" used in this application is a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the word can be replaced by other expressions.

[0039] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. The elements defined by the sentence "includes a..." do not exclude the existence of other identical elements in the process, method, commodity or device that includes the elements.

[0040] In the description of the embodiments of the present application, "plurality" means two or more than two. The following terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0041] In addition, flow charts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, the various steps may be processed in reverse order or simultaneously. At the same time, other operations may also be added to these processes, or a certain step or several steps of operations may be removed from these processes.

[0042] Reference Figure 1 , is a flow chart of an optional example of a 3D reconstruction method based on the individual kinematic calibration of a line structured light point set proposed in the present invention. The method can be applied to a computer device. The 3D point cloud reconstruction method proposed in this embodiment may include but is not limited to the following steps:

[0043] Step S1, rigidly combining the area array camera and the straight line structured light emitter, and installing them on a five-axis motion platform to obtain a measuring device;

[0044] Among them, the component assembly is completed and the line structured light stripes are within the camera's field of view.

[0045] Step S2, calibrating the structural parameters of the motion platform of the measuring device using the standard value of the standard sphere radius and the line structured light scanning data to obtain a calibrated measuring device;

[0046] S2.1. Fix the standard ball at the center of the end flange of the five-axis motion platform;

[0047] S2.2, controlling the five-axis motion platform to move, and obtaining scanning data of the standard ball at different positions;

[0048] Specifically, under the condition that the line structured light can illuminate the surface of the standard ball, the platform moves arbitrarily to obtain the scanning data of the standard ball at various postures.

[0049] S2.3. Construct a kinematic model and a kinematic error model based on the influence of each axis of the five-axis motion platform on the end, and determine the error parameter items;

[0050] S2.4, solving the spherical arc point cloud in the terminal coordinate system and taking multiple frames to fit the sphere center to obtain the initial sphere center position;

[0051] S2.5, constructing an objective function according to the three-dimensional information of the spherical arc point cloud, the initial sphere center position and the standard radius of the standard sphere;

[0052] S2.6. Based on the objective function, all the spherical arc point sets are monomerized and directly used in error identification, so as to complete the calibration of the motion platform structure parameters and obtain the calibrated measuring device.

[0053] Step S3, using the calibrated center position of the standard sphere and the standard radius of the standard sphere as constraints, calibrating the position relationship of the line scan space point set to obtain an instant point cloud calibration matrix;

[0054] Step S4, controlling the five-axis motion platform to move and acquiring scanning data of the measured object at different positions and postures;

[0055] Step S5: Based on the calibrated measuring device, automatically complete the reconstruction of a high-quality three-dimensional model of the multi-pose scan of the measured object according to the scanning data and the real-time point cloud calibration matrix.

[0056] In some feasible embodiments, in S2.3, it specifically includes:

[0057] Construct a kinematic model. The kinematic modeling refers to Figure 2 :

[0058] According to the impact on the end, the five-axis platform can be divided into translation axis and rotation axis. Since the translation movement of the machine tool does not affect the rotation movement, the following model is established for the translation axis first:

[0059]

[0060] Among them, a 11 、a 12 、a 13 、a 21 、a 22 、a 23 、a 31 、a 32 、a 33 are 9 parameters related to the yaw coefficient, which describes the yaw degree of each translation axis; k1, k2, k3 are 3 parameters related to the pulse motion ratio, which describes the proportional relationship between the encoder feedback unit pulse motion and the machine vision measurement value; X, Y, Z are encoder feedback quantities, which describe the motion of the end along each axis; x, y, z are 3 parameters related to the initial deviation, which describes the deviation in the X, Y, and Z directions between the origin of the base coordinate system established by the hand-eye relationship and the actual selected machine tool origin. Taking the five-axis motion platform mentioned in this article as an example, the intersection of the A axis and the C axis is selected as the machine tool origin.

[0061] Simplifying the above formula, we get:

[0062]

[0063] The following model is established for the transmission relationship between the translation axis and the rotation axis:

[0064]

[0065] Among them, A is the encoder feedback around the X-axis, a is the initial deviation around the X-axis, and γ and θ are the two rotational degrees of freedom required for the transfer between the translation axis coordinate system and the rotation axis coordinate system.

[0066] The following model is established for the transmission relationship between the rotating axes:

[0067]

[0068] Among them, C is the encoder feedback around the Z axis, c is the initial deviation around the Z axis, and d4 is the length of the connecting rod between the rotating axes.

[0069] Finally, the kinematic model can be obtained by combining the above formulas:

[0070]

[0071] Construct a kinematic error model:

[0072] In the above-mentioned kinematic model, all the motion platform structural parameters except X, Y, Z, A, and C are fixed values, and the theoretical values ​​used are determined by the three-dimensional model of the platform. Since errors are inevitably introduced during the manufacturing and assembly of the platform, these theoretical values ​​may have errors, which may cause the results calculated by the motion platform structural parameters to deviate from the actual motion results. Therefore, it is necessary to construct a kinematic error model for the five-axis motion platform and calibrate the motion platform structural parameters containing error terms. So we determine The error model is as follows:

[0073]

[0074]

[0075]

[0076]

[0077] From the above formula, we can see that the kinematic error model contains 17 error terms.

[0078] In some possible embodiments, in S2.4 and S2.5:

[0079] First, the center point P of the line structured light stripe in the camera coordinate system is solved by the camera intrinsic parameter matrix and the light plane equation in the camera coordinate system. camera, and then rely on the hand-eye transformation matrix With the kinematic model Transfer the 3D point cloud to the platform end coordinate system to obtain the spherical surface arc point cloud P in the end coordinate system. end , the conversion formula is as follows:

[0080]

[0081] The camera intrinsic parameter matrix and the light plane equation in the camera coordinate system are obtained by camera calibration and light plane calibration respectively. There are mature calibration methods for both, which will not be elaborated here. It is particularly important to emphasize that the hand-eye transformation matrix is ​​obtained by fitting the motion direction of each axis and then orthogonalizing it, without introducing kinematic parameter errors. In addition, since the actual structural parameter information of the motion platform is not combined during light plane calibration, it is inevitable that there will be deviations in light plane solution, which will affect the accuracy of single-frame line structured light point cloud solution. It is necessary to subsequently calibrate the structural parameters of the motion platform to compensate for the errors introduced by the insufficient light plane solution accuracy, thereby ensuring the quality of the line structured light 3D reconstruction model.

[0082] Take multiple frames of non-collinear point cloud data to calculate the sphere center Q center , the center position of the sphere is used as the initial position and is also described by the end coordinate system. Using the arc point cloud P of the sphere surface in the end coordinate system end With the initial sphere center Q center The difference between the distance and the standard radius r of the standard sphere constructs the objective function as follows:

[0083] Δr=||P end -Q center || 2 -r 2

[0084] In some possible embodiments, in S2.6:

[0085] The physical meaning of error parameter identification is to minimize the error between the model output and the actual observation data by adjusting the error term. For the objective function proposed in this paper, firstly, the multi-frame non-collinear 3D point cloud data obtained by the line structured light system scanning is transferred to the platform end coordinate system based on the feedback of each axis encoder and the initial motion platform structure parameters, and the theoretical value of the arc point cloud of the spherical surface in the end coordinate system is obtained:

[0086]

[0087] Calculate the center of the sphere using the above theoretical values The sphere center position as the initial position may contain errors Δx, Δy, and Δz in the XYZ directions.

[0088] Then, based on the encoder feedback of each axis and the structural parameters of the motion platform with error, all three-dimensional point clouds scanned by the line structured light system are transferred to the platform end coordinate system to obtain the measured value of the arc point cloud on the spherical surface in the end coordinate system:

[0089]

[0090] Since the arc point cloud on the spherical surface is distributed on the spherical surface and is constrained by the radius and center of the standard sphere, all observation data can be directly involved in the identification after being monomerized into point sets. The monomerized point set is expressed as:

[0091]

[0092] Where p represents a single point, P represents a point set, and q center represents the initial sphere center point determined by multi-frame line scanning point cloud, so p end Indicates the point where the data obtained by line scanning is resolved to the end coordinate system. Represents the point set of all measured values ​​obtained by line structured light scanning, and ε is a tiny amount.

[0093] At the same time, due to the rotation axes A and C of the five-axis motion platform, when the center of the standard sphere is solved together with the scanned point cloud in multiple positions, the interference caused by the accuracy of the line structured light 3D point cloud solution can be minimized to ensure the effectiveness of recognition. This avoids the problem that the center of each point cloud deviates from the actual solution when the accuracy of the 3D point cloud solution is insufficient for a single frame of line structured light point cloud, resulting in the difficulty in accurately identifying the error parameters. After monomerization and the initial sphere center point set The only element Substitute into the objective function and convert to matrix form:

[0094]

[0095] Where N is the size of the point set, J k is the error matrix, which is calculated based on all the observed data, and Δq is the error parameter vector to be solved, including 3 items carried by the initial sphere center, and 17 items covered by the structural parameters of the motion platform with errors, a total of 20 error parameters. By using the influence of the initial sphere center error and the structural parameter errors of each motion platform on the measurement center and measurement radius of the standard sphere, these 20 error parameters can be identified through the identification algorithm, thereby completing the kinematic calibration.

[0096] In some feasible embodiments, the step S3 specifically includes:

[0097] Since the five-axis motion platform has two rotation axes, A and C, the center position of the standard ball obtained by fitting the arc point cloud of the ball surface under various postures is not easily affected by the accuracy of the line structured light three-dimensional point cloud solution. Therefore, the center position of the standard ball after kinematic calibration can be used as the ideal center At the same time, since the accuracy of line structured light 3D point cloud solution is mainly affected by the accuracy of light plane solution, when the light plane equation obtained by light plane calibration does not completely coincide with the actual light plane, it will cause position deviation of line structured light 3D point cloud solution in the XYZ direction. This position deviation can be compensated by calibrating the diagonal matrix with error terms. The deviation diagram is shown in Figure 2. Figure 3 Therefore, the present invention uses the ideal sphere center position and the standard radius r of the standard sphere as constraints to achieve the calibration of the spatial position relationship of the line-to-line scanning point set, thereby improving the reconstruction accuracy of the three-dimensional point cloud model. The objective function used in the calibration is as follows:

[0098]

[0099] in is the center position of the standard ball after kinematic calibration, that is, the ideal center position. is the measured value of the arc three-dimensional point cloud of the spherical surface in the terminal coordinate system, which is composed of the initial value x, y, z of the point cloud coordinates and the position calibration diagonal matrix The elements on the diagonal of the diagonal matrix are the position error coefficients s1, s2, and s3, that is, The error model can be constructed as follows:

[0100]

[0101] The three error parameters are identified using the identification algorithm to obtain the real-time point cloud position calibration matrix. The absolute accuracy of the line scanning point set and the reconstruction accuracy of the three-dimensional point cloud model can be further improved.

[0102] In some feasible embodiments, the step S5 specifically includes:

[0103] After completing the above kinematic calibration and point cloud position calibration, the motion accuracy of the platform and the absolute accuracy of the line scan point set are guaranteed. Therefore, by controlling the motion of each axis of the five-axis platform, the scanning data of the measured object in different positions is obtained, and the center point of the line structured light stripe in the camera coordinate system is solved by using the camera intrinsic parameter matrix and the light plane equation in the camera coordinate system. The three-dimensional information is transformed by the hand-eye transformation matrix The inverse kinematic transformation matrix after kinematic calibration And the position calibration matrix after point cloud position calibration The scanned point cloud at each posture is transferred to the terminal coordinate system to obtain a high-precision three-dimensional point cloud that conforms to the shape of the workpiece being measured. Automatically complete high-quality 3D model reconstruction of the test piece from multiple pose scans.

[0104]

[0105] like Figure 4 As shown, a three-dimensional reconstruction system comprises:

[0106] A device fixing module is used to rigidly combine the area array camera and the one-line structured light emitter, and install them on a five-axis motion platform to obtain a measuring device;

[0107] A calibration module, using a standard value of a standard sphere radius and line structured light scanning data to calibrate the structural parameters of the motion platform of the measuring device to obtain a calibrated measuring device;

[0108] The point cloud calibration module uses the calibrated center position of the standard sphere and the standard radius of the standard sphere as constraints to calibrate the spatial position relationship of the line scan point set and obtain the instant point cloud calibration matrix;

[0109] A scanning module, used to control the movement of the five-axis motion platform and obtain scanning data of the measured object in different positions and postures;

[0110] The point cloud reconstruction module, based on the calibrated measuring device, uses the scanning data and the real-time point cloud calibration matrix to automatically complete the high-quality three-dimensional model reconstruction of the multi-pose scanning of the measured object.

[0111] The contents of the above method embodiments are all applicable to the present system embodiments. The functions specifically implemented by the present system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0112] A 3D reconstruction device based on the kinematic calibration of a line structured light point set:

[0113] at least one processor;

[0114] at least one memory for storing at least one program;

[0115] When the at least one program is executed by the at least one processor, the at least one processor implements the three-dimensional reconstruction method based on the individualized kinematic calibration of the line structured light point set as described above.

[0116] The contents of the above method embodiments are all applicable to the present device embodiments. The functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0117] A storage medium stores instructions executable by a processor, wherein the instructions executable by the processor are used to implement the above-mentioned three-dimensional reconstruction method based on the individualized kinematic calibration of a line structured light point set when executed by the processor.

[0118] The contents of the above method embodiments are all applicable to the present storage medium embodiments. The functions specifically implemented by the present storage medium embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0119] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A three-dimensional reconstruction method based on the kinematic calibration of a line structured light point set, characterized in that: The following steps are involved: The area array camera and the one-line structured light emitter are rigidly combined and mounted on a five-axis motion platform to obtain a measuring device; Using the standard value of the standard sphere radius and the line structured light scanning data, calibrate the structural parameters of the motion platform of the measuring device to obtain a calibrated measuring device; Taking the calibrated center position of the standard sphere and the standard radius of the standard sphere as constraints, the spatial position relationship of the line scan point set is calibrated to obtain the instant point cloud calibration matrix; Controlling the movement of the five-axis motion platform and acquiring scanning data of the measured object in different positions and postures; Based on the calibrated measuring device, the scanning data and the real-time point cloud calibration matrix are used to complete the high-quality three-dimensional model reconstruction of the multi-pose scanning of the measured object.

2. According to claim 1, a three-dimensional reconstruction method based on the individual kinematic calibration of a line structured light point set is characterized in that: The step of calibrating the motion platform structural parameters of the measuring device by using the standard value of the standard sphere radius and the line structured light scanning data to obtain the calibrated measuring device specifically includes: Fix the standard ball at the center of the flange at the end of the five-axis motion platform; Controlling the movement of the five-axis motion platform and acquiring scanning data of the standard ball in different positions and postures; According to the influence of each axis of the five-axis motion platform on the end, the kinematic model and kinematic error model are constructed, and the error parameter items are determined; Solve the spherical arc point cloud in the terminal coordinate system and take multiple frames of point cloud to fit the sphere center to obtain the initial sphere center position; Constructing an objective function based on the three-dimensional information of the spherical arc point cloud, the initial sphere center position and the standard radius of the standard sphere; Based on the objective function, all the spherical arc point sets are monomerized and directly involved in error identification, so as to complete the calibration of the motion platform structure parameters and obtain the calibrated measuring device.

3. The three-dimensional reconstruction method based on the kinematic calibration of a line structured light point set according to claim 2, characterized in that: The kinematic model is expressed as follows: in, represents the overall kinematic model, represents the translation axis model, Represents the transfer relationship model between the translation axis and the rotation axis, Represents the transmission relationship model between the rotating axes, A is the encoder feedback around the X-axis, a is the initial deviation around the X-axis, γ and θ are the two rotational degrees of freedom required for the transmission between the translation axis coordinate system and the rotation axis coordinate system, C is the encoder feedback around the Z-axis, c is the initial deviation around the Z-axis, d4 is the length of the connecting rod between the rotating axes; b 11 、b 12 、b 13 are three proportional coefficients related to the X-axis yaw coefficient and pulse motion ratio, b 21 、b 22 、b 23 are three proportional coefficients related to the Y-axis yaw coefficient and pulse motion ratio, b 31 、b 32 and b 33 are three proportional coefficients related to the Z-axis runout coefficient and pulse motion ratio; d1, d2, d3 are the origin deviations in the X-axis, Y-axis, and Z-axis directions respectively; X, Y, and Z represent the encoder feedback values ​​of the corresponding axes.

4. The three-dimensional reconstruction method based on the kinematic calibration of a line structured light point set according to claim 2, characterized in that: The objective function is expressed as follows: Δr=||P end -Q center || 2 -r 2 Among them, Q center represents the initial sphere center of the fitting, P end It represents the spherical arc point cloud in the terminal coordinate system, and r represents the standard radius of the standard sphere.

5. The three-dimensional reconstruction method based on the individual kinematic calibration of line structured light point set according to claim 4, characterized in that: The conversion formula of the spherical arc point cloud in the terminal coordinate system is as follows: in, represents the hand-eye transformation matrix, P camera Indicates the center point of the line structured light stripe in the camera coordinate system.

6. The three-dimensional reconstruction method based on the individual kinematic calibration of line structured light point sets according to claim 2, characterized in that: Take multiple frames of non-collinear spherical arc point cloud data to fit the center of the sphere.

7. The three-dimensional reconstruction method based on the kinematic calibration of a line structured light point set according to claim 2, characterized in that: The step of completing high-quality three-dimensional model reconstruction of the multi-pose scan of the measured object based on the calibrated measuring device using the scanning data and the real-time point cloud calibration matrix specifically includes: Based on the calibrated measuring device, according to the camera intrinsic parameter matrix and the light plane equation in the camera coordinate system, the three-dimensional information of the center point of the line structured light stripe in the camera coordinate system is solved; By combining the hand-eye transformation matrix, the calibrated inverse kinematic transformation matrix and the real-time point cloud calibration matrix, the scanning data of the test piece in different postures are converted to the terminal coordinate system, and high-quality three-dimensional model reconstruction of the test piece in multi-posture scanning is automatically completed.

8. A three-dimensional reconstruction system, characterized in that: The method for performing the three-dimensional reconstruction based on the linear structured light point set monomerized kinematic calibration as claimed in claim 1 comprises: A device fixing module is used to rigidly combine the area array camera and the one-line structured light emitter, and install them on a five-axis motion platform to obtain a measuring device; A calibration module, using a standard value of a standard sphere radius and line structured light scanning data to calibrate the structural parameters of the motion platform of the measuring device to obtain a calibrated measuring device; The real-time point cloud calibration module uses the calibrated center position of the standard sphere and the standard radius of the standard sphere as constraints to calibrate the spatial position relationship of the line scan point set and obtain the real-time point cloud calibration matrix; A scanning module, used to control the movement of the five-axis motion platform and obtain scanning data of the measured object in different positions and postures; The point cloud reconstruction module completes high-quality three-dimensional model reconstruction of the multi-pose scanning of the measured object based on the calibrated measuring device and the scanning data and the real-time point cloud calibration matrix.

Images