关键词: 机器视觉, 图像匹配, 关键轮廓特征, 图像金字塔, 仿射变换

Abstract: A real-time image matching method based on the vector features of contours is proposed to achieve quickly and accurately target location. The input is the [X/Y] direction vector features of the key contours. This paper computes the best constructed levels of image pyramid, gets the rotated angle step and scale step of template on every pyramid level, according to template image. On the highest level of image pyramid, it firstly removes positions where target exists impossibly. Then the paper constructs local region and locate target synchronously on the other levels. Experiments show that this method is robust against occlusion, nonlinear illumination, defocus, low contrast and so on. It needs some milliseconds and the recognition rate achieves 97% above. Target can be located at any coordinate, angle and scale, so it can satisfy industrial requirements.

Key words: machine vision, image matching, features of the key contours, image pyramid, affine transformation