Minimal object measurement system calibration method based on general imaging model

Abstract

The invention discloses a minimal object measurement system calibration method based on a general imaging model. A planar coordinate system is established on the plane of a calibration board, three calibration board images of different attitudes are obtained by a camera and then are subjected to deblurring, and pixel coordinates of a center of circle are obtained by ellipse fitting. The method also comprises steps that (3) a general imaging model is used to find a corresponding light equation on a world coordinate system of each pixel of the images obtained by the camera; (4) a phase position of the calibration board is obtained through an eight-step phase shifting method and a Gray code method, the coordinates of the center of circle obtained by the camera are matched with the coordinates of the center of circle of a projector according to the phase position, and a light equation of the projector, corresponding to each pixel, is obtained using the same method adopted by (3); and (5) an intersection point of light found in the camera and the projector of each pixel is computed to obtain three dimensional coordinates of an object. The invention improves the general imaging model, enables equipment to be simple and easy to implement, and gets rid of restrictions of a displacement bench in acquisition of the precise displacement.

Description

technical field [0001] The invention relates to a calibration method for a tiny object measurement system based on a general imaging model, and belongs to the field of three-dimensional information reconstruction in machine vision. Background technique [0002] With the development of micro-nano technology, various products in people's daily life are developing in the direction of portability, which makes the product volume smaller and smaller, and the measurement of tiny objects becomes more and more important, which affects the development of industrial technology . [0003] For the grating projection measurement of small objects, the field of view and depth of field are required to be small, so the traditional pinhole camera cannot accurately obtain the height change of the three-dimensional object. Compared with traditional microscopes, telecentric lenses have incomparable advantages such as high resolution, almost zero distortion, increased degrees of freedom and const...

AI Technical Summary

Problems solved by technology

At the same time, a self-convolution blind deblurring method is proposed to solve the defocus problem caused by the small depth of field of the telecentric lens

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