Three-dimensional matching detection method for complex curved surface parts based on electric field properties

Abstract

The invention belongs to the technical field of detection of part processing errors, and discloses a method for detecting the size of a complex curved part in a three-dimensional matching manner based on electric-field properties. The method comprises the following steps: scanning and measuring a part to be detected so as to obtain measurement point clouds, and unifying a design model and a measurement model in the same coordinate system; defining two point clouds in an electrified body electric field, and giving a certain amount of charges; respectively calculating the electric potentials of the design model and a scanning model at the position of a probe charge by taking the origin of the coordinate as the probe charge; calculating electric field intensities of various points in a gravity centre neighbour field of two electron clouds, and acquiring a rigid body transformation matrix according to singular value decomposition; and updating and measuring the electron clouds from this, and circularly calculating the electric potential difference between the two electron clouds at the origin till an end condition is satisfied. By means of the invention, the problems of being sensitive to an initial position and easily fallen into local optimum in the existing matching technology can be effectively solved; and the method disclosed by the invention is particularly suitable for three-dimensional high-precision matching purposes of a large-scale depth image.

Description

technical field [0001] The invention belongs to the technical field of component processing error detection, and more specifically relates to a three-dimensional matching detection method for complex curved surface component sizes based on electric field properties. Background technique [0002] 3D point cloud matching technology has a wide range of applications in the fields of processing error detection, reverse engineering, pattern recognition, and medical image processing. In the application field of machining error detection, the machining error is usually determined by comparing the matching error between the measurement model and the design model. However, since the design and measurement point clouds to be matched are in the design coordinate system and the measurement coordinate system respectively, it is necessary to unify the coordinate systems of the two point clouds. In addition, since the initial positions of the two point clouds are unknown, and the models to...

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Problems solved by technology

[0004] In addition, further searches found that CN104537638A published a 3D image registration method and system, which uses weighted direction histograms to obtain transformation matrices, but this invention is mainly used for medical image registration under local deformation, which belongs to non-rigid body alignment, and For the processing quality detection of complex surface parts, rigid body transformation matrix is ​​required, and there is an essential difference between the two; CN104217458A discloses a fast registration method for three-dimensional point clouds, and the key of the proposed method is to establish a binary image of two point clouds. One-dimensional projection coordinate system and calculate the number of points that one point cloud falls into another point cloud in two-dimensional space, but for point clouds with large complex surfaces, there is a point overlap problem when projecting from three-dimensional to two-dimensional coordinates , there will be certain errors in statistics by this method; CN103295228A discloses a fast data registration method in a three-dimensional scanning system, which records the rotation angle of the turntable multiple times through the method, and performs registration of point cloud data at different angles based on this value However, the rotation error of the turntable is unavoidable in actual operation, which will directly affect the registration accuracy, and the workpieces to be measured with different sizes and shapes will have different requirements on the turntable, which increases the complexity and cost of the system; Finally, CN103514625A discloses a 3D reconstruction method based on multi-view adaptive feature registration, which obtains 3D image data by processing pixels, but has high requirements for measuring instruments

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