High-definition measurement gray level image based three-dimensional morphology evaluation method for part surfaces

Abstract

The invention provides a high-definition measurement gray level image based three-dimensional morphology evaluation method for complex part surfaces. The method includes the steps: firstly, measuring the surface of a complex part by a three-dimensional high-resolution surface morphology measurement technique, and converting measured three-dimensional high-density point cloud data into a gray level image; secondly, calculating a gray level co-occurrence matrix, and excluding pixels of external boundaries and internal holes of the part to obtain an effective gray level co-occurrence matrix; finally, through the effective gray level co-occurrence matrix, calculating characteristic value entropy and contrast which are respectively used for evaluating randomness of the three-dimensional morphology of the complex part and magnitude of a local error of the three-dimensional shape. By the method, the three-dimensional morphology of the surface of a large-size complex part comprising holes can be evaluated, the shortcomings that a two-dimensional morphology evaluation method is prone to undetection and a three-dimensional micromorphology method cannot directly calculate discrete data of the surface of the complex part are overcome, and an evaluation system for relevant part surface morphology geometrical characteristics of products is supplemented.

Description

technical field [0001] The invention belongs to the technical field of part surface topography detection and image processing, in particular to a method for evaluating the three-dimensional topography of complex part surfaces based on high-definition measured grayscale images, especially by calculating the grayscale co-occurrence matrix of high-definition measured grayscale images , mine the height information and spatial information contained in the measurement data, and realize the quantitative evaluation of the three-dimensional topography of the surface of complex parts. Background technique [0002] Automobile engine manufacturing requires precise testing technology to accurately judge whether the engine quality indicators and process parameters meet the design requirements. Since the three-dimensional topography of the joint surface of the engine block and cylinder head directly affects the sealing and reliability of the engine combustion chamber, the quality of the th...

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Problems solved by technology

[0005] In order to overcome the deficiencies of the two-dimensional shape evaluation method and the three-dimensional microscopic shape evaluation method in the prior art in evaluating the three-dimensional shape of the surface of complex parts with a side length of hundreds of millimeters, the present invention proposes a method based on high-definition measurement gray Evaluation method of 3D surface topography of complex parts based on high-resolution images

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