CN114111639A - Correction method and device for surface structured light three-dimensional measurement system - Google Patents
Correction method and device for surface structured light three-dimensional measurement system Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
- G01B11/254—Projection of a pattern, viewing through a pattern, e.g. moiré
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Abstract
The application provides a correction method and equipment of a surface structured light three-dimensional measurement system, which comprises the steps of correcting distortion in the system and obtaining a world coordinate system of a distortion-free measurement point; dividing an effective working range in a first direction under a world coordinate system into N intervals; acquiring surface data of the standard correction block in each interval; determining a corresponding first coordinate value in each subarea, wherein each subarea is obtained by dividing each interval according to a preset size along a second direction and a third direction of a world coordinate system; performing surface fitting on the first coordinate values of all the sub-areas in each interval to determine a reference correction surface; determining the compensation amount of each sub-area, wherein the compensation amount is the average value of the deviation amount of the corresponding surface data and the reference correction surface; and establishing a lookup table of sub-regions and compensation quantities in different intervals under the world coordinate system of the distortion-free measuring point. On the basis of distortion correction of a camera and a projector, system errors are eliminated, the measurement precision of the system is improved, and the measurement requirement of a high-precision measured object is met.
Description
Technical Field
The application relates to the technical field of surface structured light three-dimensional measurement, in particular to a correction method and correction equipment of a surface structured light three-dimensional measurement system.
Background
The surface structured light three-dimensional measurement system comprises a camera and a projector, but the lenses of the camera and the projector are distorted, so that the measurement precision of the system is influenced; in the practical application of the surface structured light three-dimensional measurement system, the measurement requirement of a high-precision measured object is higher and higher, so that the correction precision requirement of the surface structured light three-dimensional measurement system is higher and higher.
The correction of the surface structure three-dimensional measurement system mainly comprises the distortion correction of a camera and a projector, wherein the projector is regarded as a reverse camera to form a binocular system with the camera, and internal parameters, distortion coefficients and external parameters of the camera and the projector are respectively calibrated through a calibration plate; then, the distortion model of the traditional camera is adopted to process different types of distortion such as radial distortion, tangential distortion and the like, and the distortion correction of the camera and the projector is respectively realized.
However, the three-dimensional measurement system with a surface structure has a measurement accuracy of mainly ten microns to several hundred microns after the distortion correction, and thus it is difficult to meet the measurement accuracy requirement of ten microns of a high-accuracy measured object.
Disclosure of Invention
The application provides a correction method and equipment of a surface structure light three-dimensional measurement system, which are used for solving the technical problem that the measurement precision of the surface structure three-dimensional measurement system is difficult to meet the measurement precision requirement of a measured object required by high-precision measurement.
In order to achieve the above object, in a first aspect, an embodiment of the present application provides a calibration method for a surface structured light three-dimensional measurement system, where the calibration method includes the following steps:
and correcting distortion in the system, and acquiring a world coordinate system of the distortion-free measuring point.
And dividing the effective working range of the first direction in the world coordinate system into N intervals.
Surface data of a standard calibration block, which is of known surface morphology, at each interval is acquired.
And determining a corresponding first coordinate value in each subarea, wherein the subareas are obtained by dividing each subarea along a second direction and a third direction of the world coordinate system according to a preset size, and the first coordinate value is an average value of the corresponding surface data in the subareas.
And performing surface fitting on the first coordinate values of all the sub-areas in each interval to determine a reference correction surface.
Determining a compensation amount for each sub-region, the compensation amount being an average of deviation amounts of the corresponding surface data and the reference correction surface.
And establishing a lookup table under a world coordinate system of the distortion-free measuring point, wherein the lookup table is a corresponding relation between sub-regions and compensation quantities under different intervals.
In one possible embodiment, the distortion in the correction system includes distortion correction of a camera and distortion correction of a projector.
In one possible embodiment, the distortion correction of the camera includes:
calibrating camera parameters, wherein the calibrating camera parameters comprise that a camera collects calibration plate images at different positions; and calibrating camera parameters according to the calibration plate image, wherein the camera parameters comprise internal parameters, external parameters and distortion coefficients of the camera.
And carrying out distortion correction on the image acquired by the camera according to the camera distortion model and the camera parameters, and determining the image after distortion correction.
In one possible embodiment, the distortion correction of the projector includes the following steps:
calibrating projector parameters, wherein the calibrating projector parameters comprise that a projector projects patterns to a calibration plate, and the patterns projected to the calibration plate are collected by a camera; and calibrating projector parameters according to the pattern projected on the calibration plate and the pattern of the calibration plate, wherein the projector parameters comprise internal parameters, external parameters and distortion coefficients of the projector.
And determining a rotation matrix and a translation matrix from the camera coordinate system to the projector coordinate system according to the camera parameters and the projector parameters.
And determining the projector pixel coordinates corresponding to the world coordinate system according to the camera distortion model, the projector parameters, the rotation matrix and the translation matrix.
And determining the pixel coordinate of the undistorted projector according to the pixel coordinate of the projector and the distortion model of the camera.
And determining a world coordinate system of the distortion-free measuring point according to the rotation matrix, the translation matrix and the pixel coordinates of the distortion-free projector.
In a possible implementation, after establishing the look-up table under the world coordinate system of the undistorted measurement point, the correction method further includes:
obtaining corresponding compensation quantity in the lookup table according to the world coordinate of the measuring point on the object to be measured;
and correcting the world coordinates of the measuring points according to the corresponding compensation amount.
In one possible embodiment, the surface data is obtained by setting the standard correction block at the center of each section.
The method comprises the steps of correcting distortion in the system, and obtaining a world coordinate system of a distortion-free measuring point; dividing an effective working range in a first direction under a world coordinate system into N intervals; acquiring surface data of a standard correction block in each interval, wherein the standard correction block has a known surface morphology; determining a corresponding first coordinate value in each subarea, wherein the subareas are obtained by dividing each interval according to a preset size along a second direction and a third direction of a world coordinate system, and the first coordinate value is an average value of corresponding surface data in the subareas; performing surface fitting on the first coordinate values of all the sub-areas under each interval to determine a reference correction surface; determining a compensation amount of each sub-region, wherein the compensation amount is an average value of deviation amounts of the corresponding surface data and the reference correction surface; and establishing a lookup table under a world coordinate system of the distortion-free measuring point, wherein the lookup table is a corresponding relation between sub-regions and compensation quantities under different intervals. The method and the device have the advantages that the system error is eliminated on the basis of distortion correction of the camera and the projector, the measurement precision of the system is improved, and the measurement requirement of a high-precision measured object is met.
In a second aspect, the present application further provides a calibration apparatus for a surface structured light three-dimensional measurement system, which employs the calibration method for a surface structured light three-dimensional measurement system in the first aspect.
The application provides a correction device of a surface structured light three-dimensional measurement system, which adopts a correction method of the surface structured light three-dimensional measurement system, eliminates system errors on the basis of distortion correction of a camera and a projector, improves the measurement precision of the system, and meets the measurement requirement of a high-precision measured object.
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In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is an imaging schematic diagram of a three-dimensional measurement system of structured light according to an embodiment of the present disclosure;
fig. 2 is a flowchart of a calibration method of a surface structured light three-dimensional measurement system according to an embodiment of the present application;
FIG. 3 is a flow chart of distortion correction for a camera according to an embodiment of the present application;
FIG. 4 is a schematic diagram illustrating the interval division of the effective working range in the first direction according to the embodiment of the present disclosure;
FIG. 5 is a schematic diagram illustrating distances between a measurement point and a fitted surface according to an embodiment of the present disclosure;
fig. 6 is a flowchart of a calibration method of a surface structured light three-dimensional measurement system according to another embodiment of the present application;
wherein: 1-a camera; 2-a projector; 3-camera image plane; 4-projector image plane; 5-a spatial plane; 6. 7-optical axis.
Detailed Description
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The surface structured light three-dimensional measurement system comprises a projector and an image pickup device. The distortion of the surface structured light three-dimensional measurement system is corrected, the high-precision three-dimensional target can be used for calibration by taking the camera equipment and the projector as a whole, and the precision of the three-dimensional target influences the measurement precision of the system by adopting the distortion correction method; the projector can be used as a reverse camera device, the surface structured light three-dimensional measurement system is a binocular system, parameters of the camera device and the projector are respectively calibrated, and distortion correction of the camera device and distortion correction of the projector are respectively realized.
The first method needs a high-precision three-dimensional target and a system modeling, and has high modeling difficulty, high cost of the high-precision three-dimensional target and high manufacturing difficulty. The second mode is insufficient in calibration precision of the projector, so that the overall measurement precision of the system is reduced, the offset measurement precision of the system is generally hundreds of micrometers to tens of micrometers, and the precision of the offset measurement precision cannot meet the measurement requirement of a high-precision measured object.
In order to solve the above problems, embodiments of the present application provide a method for correcting a surface structured light three-dimensional measurement system, which improves measurement accuracy of the system by correcting distortion of the system and eliminating system errors, and meets measurement requirements of a high-accuracy measured object.
The camera shooting equipment in the surface structure three-dimensional measuring system is used for collecting images, and the projection equipment is used for projecting light images with specific structures. In some embodiments, the image capture device may be a video camera or a camera.
As shown in FIG. 1, the imaging schematic diagram of the surface structured light three-dimensional measurement system includes a projector 2 and a camera 1, and the spatial plane 5 where the world coordinate system Xw-Yw-Zw is located has the spatial point P coordinate (X coordinate) of the surface of the object to be measuredW P，YW P，ZW P) Corresponding to a pixel point P in the camera image plane 3cCorresponding to a pixel point P in the projector image plane 4pThe projector image plane 4 is imaged in the direction of the optical axis 6 of the projector and the camera image plane 3 is imaged in the direction of the optical axis 7 of the camera.
As shown in fig. 2, the calibration method of the surface structured light three-dimensional measurement system includes the following steps:
s101, correcting distortion in the system, and obtaining a world coordinate system of the distortion-free measuring point.
The distortion in the correction system comprises camera distortion correction and projector distortion correction, and the world coordinate system of the distortion-free measuring points is the coordinate values of each measuring point which are readjusted under the world coordinate system.
Wherein the distortion correction of the camera comprises: firstly, calibrating camera parameters, then carrying out distortion correction on an image acquired by a camera according to a camera distortion model and the camera parameters, and determining the image after distortion correction.
The camera parameters can be calibrated by selecting a proper calibration plate according to a Zhang Zhengyou calibration method, acquiring a plurality of groups of calibration plate images at different positions, and calibrating the camera parameters according to the calibration plate images, wherein the camera parameters comprise camera internal parameters, external parameters and distortion coefficients, and the internal parameters comprise the equivalent focal length, principal point coordinates and lens distortion of a camera lens; the external parameters comprise a rotation matrix and a translation vector which are converted into an original coordinate system by a camera coordinate system.
In some embodiments, the image of the calibration plate may be a checkerboard or a circular lattice.
According to the camera distortion model, radial distortion and tangential distortion can be corrected, in the distortion correction process, an undistorted image is obtained through a known distorted image, and specifically, the mapping relation between the distorted image and the undistorted image can be obtained through the camera distortion model and camera parameters.
As shown in fig. 3, the camera parameters are added to the camera distortion model, and a distortion correction correspondence table is determined; in the distortion correction correspondence table, the coordinates (u) of the distorted image are calculatedd，vd) Determining the distortion quantity (delta u, delta v); and obtaining the corresponding undistorted image coordinate according to the distortion amount, obtaining the gray value of the coordinate by a difference method, and determining the image after distortion correction.
Through the steps, radial distortion and tangential distortion of the image collected by the camera are eliminated, and the measurement precision of the surface structured light three-dimensional measurement system is improved.
The projector distortion correction method comprises the following steps:
and calibrating projector parameters.
Because the projector can not collect images, calibrating the parameters of the projector by using a camera which is calibrated and corrected in distortion, the method specifically comprises the following steps: firstly, projecting a pattern to a calibration plate by a projector, and collecting the pattern projected to the calibration plate by a camera; and calibrating projector parameters according to the pattern projected on the calibration plate and the pattern of the calibration plate, wherein the projector parameters comprise internal parameters, external parameters and distortion coefficients of the projector.
And determining a rotation matrix R and a translation matrix T from a camera coordinate system to a projector coordinate system according to the camera parameters and the projector parameters.
Distortion correction for a projector is also correction for radial distortion and tangential distortion, and since the projector is used as a reverse camera, correction after coordinate system conversion is required. The system is projected by a projector, and a camera collects a specific structured light pattern to determine the original world coordinates of the space points on the space plane.
And determining a projector pixel coordinate corresponding to the world coordinate system, namely the pixel coordinate of the projector image plane, which is similar to the pixel coordinate of the camera image plane, according to the camera distortion model, the projector parameters, the rotation matrix and the translation matrix.
And then determining the pixel coordinate of the undistorted projector according to the pixel coordinate of the projector and the distortion model of the camera.
And finally, determining a world coordinate system of the distortion-free measuring point according to the rotation matrix, the translation matrix and the pixel coordinate of the distortion-free projector.
In some embodiments, the correction step of the projector may be iterated multiple times to achieve better correction, but that consumes more computing time, and whether to iterate the correction step may be selected based on a particular measure.
Through the process, the influence of projector distortion on the surface structured light three-dimensional measurement system is reduced, the precision of the world coordinate system for determining the distortion-free measurement points is higher, and the measurement precision of the system is improved.
And S102, dividing the effective working range of the first direction in the world coordinate system into N intervals.
In a world coordinate system in which the surface structured light three-dimensional measurement system determines distortion-free measurement points in correcting system distortion, an effective working range in a first direction (Z direction) is divided into N sections, as shown in fig. 4, the effective working range in the Z direction is divided into N sections from Z ═ D to Z ═ D, where the center Z ═ 0, and the size of each section is Δ D.
S103, acquiring surface data of the standard correction block in each section.
The standard proof mass is of known surface morphology. The standard correcting block can be a plane block, a step block, a spherical block and other correcting blocks with known surface shapes.
The standard correcting block has good surface flatness, low cost, easy realization and good imaging effect, and the manufacturing error is less than 10 microns.
The surface data is obtained by setting the standard correction block at the center of each section. As shown in fig. 4, the shooting surface of the standard correction block is adjusted to be within the corresponding shooting area, for example, for an interval where n is 1, the surface of the standard correction block used for shooting is placed within the interval, and a corresponding set of surface data is collected; and until the N-N interval, placing the surface used for shooting by the standard correction block in the interval, and acquiring a corresponding set of surface data, wherein all the surface data are 3D curved surface data. The standard correction block is used as a shot object to acquire 3D curved surface data, and the integrity of the acquired data is ensured.
And S104, determining a corresponding first coordinate value in each sub-area.
The sub-regions are obtained by dividing each region according to a preset size along a second direction (X direction) and a third direction (Y direction) of a world coordinate system, and the first coordinate value is an average value of corresponding surface data under the sub-regions. Dividing the surface data obtained in each interval into sub-areas with the same size along the XY direction, wherein the sub-areas can be divided according to the preset size, and the unit of the preset size in the XY direction is a pixel; and taking the Z value of the corresponding surface data in each sub-area as an average value to obtain a first coordinate value.
And S105, performing surface fitting on the first coordinate values of all the sub-regions in each interval to determine a reference correction surface.
In some embodiments, for surface fitting, 3D surface data captured in N intervals may be fitted to N independent surfaces for correction amount calculation, or all the data may be fitted to N parallel surfaces for correction amount calculation.
And S106, determining the compensation amount of each sub-area.
The compensation amount is an average value of deviation amounts of the corresponding surface data and the reference correction surface. As shown in fig. 5, the distance, i.e., the amount of deviation, of each measurement point in the surface data in each sub-region from the reference correction surface (fitted surface) is calculated; and averaging all deviation amounts in the sub-area to obtain the compensation amount of the sub-area.
S107, establishing a lookup table of sub-regions and compensation quantities in different intervals under the world coordinate system of the distortion-free measuring point.
The lookup table is the corresponding relation between the sub-region and the compensation amount in different intervals.
For example, the effective working range of the surface structured light three-dimensional measurement system in the Z direction is-10 to +10mm, the surface structured light three-dimensional measurement system can be divided into 20 sections by taking 1mm as an interval, 3D curved surface data is acquired by taking a standard correction block as a shot object in the shooting range of each section, each surface data of the 3D curved surface data is divided into sub-sections along the XY direction by the size of 10 x 10pixel, the average value of the Z value in each sub-section is taken as a first coordinate value of the sub-section, a reference correction surface of the section is obtained by fitting the curved surface with the first coordinate values of all the sub-sections of the surface in one section, the average value of the deviation amount of each sub-section to the fitting curved surface is calculated as the compensation amount of the section in the height section, a lookup table is established according to the height section and the XY coordinate section of the section, and the compensation amount is stored in the lookup table for use in correction. In a specific implementation, the lookup table is a three-dimensional structure, wherein the table corresponding to an interval of 1mm to 2mm in the Z direction is as follows:
| Index X, Y | 0～9 | 10～19 | 20～29 | 30～39 | …… |
| 0～9 | 0.032 | 0.026 | 0.017 | 0.022 | …… |
| 10～19 | 0.021 | 0.017 | 0.045 | 0.026 | …… |
| 20～29 | 0.026 | 0.022 | 0.032 | 0.021 | …… |
| 30～39 | 0.045 | 0.032 | 0.021 | 0.017 | …… |
| …… | …… | …… | …… | …… | …… |
Wherein, the unit of the index of X, Y direction is pixel, and the unit of the compensation amount is millimeter mm.
When the measurement point of the measured object is corrected after the lookup table is established, as shown in fig. 6, the correction method further includes the following steps:
and S108, obtaining corresponding compensation quantity in the lookup table according to the world coordinate of the measuring point on the object to be measured.
And S109, correcting the world coordinates of the measuring points according to the corresponding compensation amount.
And searching the height interval and the area of the measuring point according to the world coordinate of the measuring point, finding the corresponding compensation quantity in the lookup table, and correcting the world coordinate of the measuring point by using the compensation quantity to obtain the world coordinate of the measuring point with the residual error eliminated.
In this embodiment, the camera and the projector in the system are respectively calibrated and corrected, and finally, the whole system is corrected by using the standard correction block. The measurement error of a small system improves the measurement precision.
The application provides a correction method of a surface structured light three-dimensional measurement system, which comprises the steps of correcting distortion in the system and determining a world coordinate system of a distortion-free measurement point; dividing an effective working range in a first direction under a world coordinate system into N intervals; acquiring surface data of a standard correction block in each interval, wherein the standard correction block has a known surface morphology; determining a corresponding first coordinate value in each subarea, wherein the subareas are obtained by dividing each interval according to a preset size along a second direction and a third direction of a world coordinate system, and the first coordinate value is an average value of corresponding surface data in the subareas; performing surface fitting on the first coordinate values of all the sub-areas under each interval to determine a reference correction surface; determining a compensation amount of each sub-region, wherein the compensation amount is an average value of deviation amounts of the corresponding surface data and the reference correction surface; and establishing a lookup table under a world coordinate system of the distortion-free measuring point, wherein the lookup table is a corresponding relation between sub-regions and compensation quantities under different intervals. The method and the device have the advantages that the system error is eliminated on the basis of distortion correction of the camera and the projector, the measurement precision of the system is improved, the measurement requirement of a high-precision measured object is met, and meanwhile, the measurement stability is also improved.
The present application further provides a calibration apparatus for a surface structured light three-dimensional measurement system, which employs the calibration method for a surface structured light three-dimensional measurement system according to the first aspect. And the system error is eliminated on the basis of distortion correction of the camera and the projector, the measurement precision of the system is improved, and the measurement requirement of a high-precision measured object is met.
The above-mentioned contents are only for explaining the technical idea of the present application, and the protection scope of the present application is not limited thereby, and any modification made on the basis of the technical idea presented in the present application falls within the protection scope of the claims of the present application.
Additionally, the order in which elements and sequences of the processes described herein are processed, the use of alphanumeric characters, or the use of other designations, is not intended to limit the order of the processes and methods described herein, unless explicitly claimed. While various presently contemplated embodiments have been discussed in the foregoing disclosure by way of example, it should be understood that such detail is solely for that purpose and that the appended claims are not limited to the disclosed embodiments, but, on the contrary, are intended to cover all modifications and equivalent arrangements that are within the spirit and scope of the embodiments herein. For example, although the system components described above may be implemented by hardware devices, they may also be implemented by software-only solutions, such as installing the described system on an existing server or mobile device.
Similarly, it should be noted that in the preceding description of embodiments of the application, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the embodiments. This method of disclosure, however, is not intended to require more features than are expressly recited in the claims. Indeed, the embodiments may be characterized as having less than all of the features of a single embodiment disclosed above.
The entire contents of each patent, patent application publication, and other material cited in this application, such as articles, books, specifications, publications, documents, and the like, are hereby incorporated by reference into this application. Except where the application is filed in a manner inconsistent or contrary to the present disclosure, and except where the claim is filed in its broadest scope (whether present or later appended to the application) as well. It is noted that the descriptions, definitions and/or use of terms in this application shall control if they are inconsistent or contrary to the statements and/or uses of the present application in the material attached to this application.
Claims (10)
1. A correction method of a surface structured light three-dimensional measurement system is characterized by comprising the following steps:
correcting distortion in the system, and acquiring a world coordinate system of a distortion-free measuring point;
dividing the effective working range of the world coordinate system in the first direction into N intervals;
acquiring surface data of a standard correction block in each interval, wherein the standard correction block has a known surface morphology;
determining a corresponding first coordinate value in each subarea, wherein the subareas are obtained by dividing each subarea along a second direction and a third direction of the world coordinate system according to a preset size, and the first coordinate value is an average value of surface data corresponding to the subareas;
performing surface fitting on the first coordinate values of all the sub-areas under each interval to determine a reference correction surface;
determining a compensation amount of each sub-region, wherein the compensation amount is an average value of deviation amounts of the corresponding surface data and the reference correction surface;
and establishing a lookup table under a world coordinate system of the distortion-free measuring point, wherein the lookup table is a corresponding relation between sub-regions and compensation quantities under different intervals.
2. The method for correcting the surface structured light three-dimensional measurement system according to claim 1, wherein the distortion in the correction system comprises distortion correction of a camera and distortion correction of a projector.
3. The method for correcting the surface structured light three-dimensional measurement system according to claim 2, wherein the distortion correction of the camera comprises:
calibrating camera parameters;
and carrying out distortion correction on the image acquired by the camera according to the camera distortion model and the camera parameters, and determining the image after distortion correction.
4. The calibration method of the surface structured light three-dimensional measurement system according to claim 3, wherein the calibrating the camera parameters comprises:
the camera collects images of the calibration plate at different positions;
and calibrating camera parameters according to the calibration plate image, wherein the camera parameters comprise internal parameters, external parameters and distortion coefficients of the camera.
5. The method for correcting the surface structured light three-dimensional measurement system according to claim 3, wherein the distortion correction of the projector comprises:
calibrating parameters of the projector;
determining a rotation matrix and a translation matrix from a camera coordinate system to a projector coordinate system according to the camera parameters and the projector parameters;
and determining a world coordinate system of the distortion-free measuring point according to the camera distortion model, the projector parameters, the rotation matrix and the translation matrix.
6. The calibration method of the surface structured light three-dimensional measurement system according to claim 5, wherein calibrating the projector parameters comprises:
the projector projects a pattern to the calibration plate, and the pattern projected to the calibration plate is collected by the camera;
and calibrating projector parameters according to the pattern projected onto the calibration plate and the pattern of the calibration plate, wherein the projector parameters comprise internal parameters, external parameters and distortion coefficients of the projector.
7. The calibration method of the surface structured light three-dimensional measurement system according to claim 5, wherein the determining the world coordinate system of the distortion-free measurement points according to the camera distortion model, the projector parameters, the rotation matrix and the translation matrix comprises:
determining projector pixel coordinates corresponding to a world coordinate system according to a camera distortion model, the projector parameters, the rotation matrix and the translation matrix;
determining the pixel coordinate of the undistorted projector according to the pixel coordinate of the projector and the distortion model of the camera;
and determining a world coordinate system of the distortion-free measuring point according to the rotation matrix, the translation matrix and the pixel coordinates of the distortion-free projector.
8. The calibration method of the surface structured light three-dimensional measurement system according to claim 1, wherein after the lookup table under the world coordinate system of the distortion-free measurement points is established, the calibration method further comprises:
obtaining corresponding compensation quantity in the lookup table according to the world coordinate of the measuring point on the object to be measured;
and correcting the world coordinates of the measuring points according to the corresponding compensation amount.
9. The calibration method of the surface structured light three-dimensional measurement system according to claim 1, wherein the surface data is obtained by arranging the standard calibration block at the center of each interval.
10. A calibration apparatus for a structured light three-dimensional measurement system, characterized in that a calibration method for a structured light three-dimensional measurement system according to any one of claims 1 to 9 is used.
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