An edge detection algorithm based on rectangular gaussian kernels for machine vision applications

Abstract

In this paper, we develop rectangular Gaussian kernels, i.e. all the rotated versions of the first order partial derivatives of the 2D nonsymmetrical Gaussian functions, which are used to convolve with the test images for edge extraction. By using rectangular kernels, one can have greater flexibility to smooth high frequency noise while keeping the high frequency edge details. When using larger kernels for edge detection, one can smooth more high frequency noise at the expense of edge details. Rectangular kernels allow us to smooth more noise along one direction and detect better edge details along the other direction, which improve the overall edge detection results especially when detecting line pattern edges. Here we propose two new approaches in using rectangular Gaussian kernels, namely the pattern-matching method and the quadratic method. The magnitude and directional edge from these two methods are computed based on the convolution results of the small neighborhood of the edge point with the rectangular Gaussian kernels along different directions. © 2009 SPIE.