Abstract: An edge detection algorithm based on eight directions sobel operator is proposed for the problem that traditional edge detection method’s result is not satisfactory. The algorithm based on eight templates of 0°,22.5°,45°,67.5°,90°,112.5°,135° and 157.5° different directions is used to detect edges better in different directions. In the detection process,we take into account that the distance of neighborhood pixel to the center pixel is different,the contribution of the neighborhood pixel to the center pixel is different. This algorithm weights the neighborhood pixel according to the Euclidean of it to the center pixel. We let the pixel nearer to the center pixel has greater weight. The experimental results show that the new algorithm can detect the image edge relatively complete,with clear contours and better continuity.

Key words: Edge detection,Sobel operator,Eight directions,Weight