Fast Eigen Template Matching Using Multiple Narrowing Down

Abstract

The template matching is the basic technique of the industrial image processing for the object detection such as the defect inspection and OCR (Optical Character Recognition). It has a problem which requires a lot of computational time for detecting the XY displacement and the rotational angle of the target object. We have proposed the eigen template method for this problem. The proposed method can efficiently calculate correlation between images using principal component analysis. However, when an input image is complicated, the method failed to detect the target object correctly. Additionally, the computational time of the method remains large still. In this paper, we propose the edge based eigen template matching method with robustness for the complex image compared with the previous method. Moreover, we describe an efficient matching algorithm for the eigen template matching using approximate nearest neighbor search. In the evaluation experiments using a simulation image and a captured image, we show that the proposed method can detect the target object faster and more robust to the complex image than the previous methods.