A subpixel localization method based on edge diffraction

摘要

The subpixel localization is an important factor to determinate measurement accuracy in using CCD vision measurement system for measuring the size of precision part. For investigating the reason of the image edge's gray-scale distribution and the edge subpixel localization calculation method of the precision part vision measurement, the influence of diffraction on the edge gray-scale distribution of the precision part's CCD image has been studied with the theory of Fresnel straight edge diffraction and the experiment, the theoretical analysis and experiment results have confirmed that the main influence factors on the edge gray-scale distribution of the precision part's CCD image were the edge diffraction and imaging parameters. An empirical formula of subpixel localization for precision part's CCD vision measurement has been given, and its rationality and practicality have been certified by the vision measurement experiment on the standard measuring gauges.