A method for calculating the principal curvature of point cloud
A calculation method and technology of principal curvature, applied in the field of point cloud measurement on the surface of engineering parts, can solve problems such as inability to highlight details, inability to accurately reflect the characteristics of large changes in the shape of the measured workpiece, and achieve the effect of increasing smoothness
Pending Publication Date: 2018-12-18
GUANGDONG UNIV OF TECH
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[0004] In order to overcome the technical defects that the existing MLS surface adopts a single fixed radius Gaussian kernel function definition method, which cannot highlight details and accurately reflect the characteristics of large shape changes along different directions at any point on the measured workpiece, the present invention provides a point Cloud Principal Curvature Calculation Method
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[0035] The accompanying drawings are for illustrative purposes only and cannot be construed as limiting the patent;
[0036] In order to better illustrate this embodiment, some parts in the drawings will be omitted, enlarged or reduced, and do not represent the size of the actual product;
[0037] For those skilled in the art, it is understandable that some well-known structures and descriptions thereof may be omitted in the drawings.
[0038] The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.
[0039] Such as figure 1 , figure 2 As shown, a point cloud principal curvature calculation method includes the following steps:
[0040] S1: Construct a free-form surface, collect point clouds on the surface to obtain Q1 and calculate the normal vector of each point in Q1;
[0041] S2: According to the obtained normal vector, select a point p in Q1, calculate the centroid in its k neighbor...
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A method for calculating the principal curvature of point cloud includes construct a free-form surface, collecting point cloud on the surface to obtain Q1 and calculating the normal vector of each point in Q1; according to the obtained normal vector, selecting a point p in Q1, calculating the center of mass in its k-neighborhood, and calculating the covariance matrix from the center of mass; calculating eigenvalues and eigenvectors according to the obtained covariance matrix; obtaining the maximum eigenvalue and the second eigenvalue and their corresponding eigenvectors by comparison, and obtaining the principal curvature is obtained by calculation. The anisotropic Gaussian kernel function is constructed according to the principal curvature and the weight function is obtained. The local weighted normal vector is constructed according to the weight function, and the local anisotropic least square surface is obtained from the weighted normal vector. Loop calculation is performed until the calculation of the last point. The invention provides a method for calculating the principal curvature of a point cloud; by using two principal curvatures as parameters of a Gaussian kernel function, the smoothness of a point cloud in a flat region fitting by an adaptive least square surface is increased, and the detail part is effectively highlighted.
Description
technical field [0001] The invention relates to the field of surface point cloud measurement of engineering parts, and more specifically, relates to a method for calculating the principal curvature of a point cloud. Background technique [0002] Three-dimensional data measurement has been widely used in the processing quality inspection, operation status monitoring and quick maintenance process of parts with complex shapes, so as to evaluate the shape and make decisions in time to avoid a large number of processing waste products or operation safety accidents. For this reason, in engineering, the reverse engineering method is often used to measure the shape of the workpiece by using a laser scanner or a three-coordinate measuring machine, and the measurement data is aligned and the surface is reconstructed, and the processing quality is evaluated by comparing with the CAD model of the workpiece. Or plan the repair area processing technology. Due to the limitation of measuri...
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Login to View More IPC IPC(8): G06F17/16G01B21/20
CPCG06F17/16G01B21/20
Inventor 王宏杰黄运保李海艳
Owner GUANGDONG UNIV OF TECH