Fuzzy Logic Based Image Edge Detection Algorithm in MATLAB

Abstract

This paper reports the implementation, in MATLAB environment, of a very simple but efficient fuzzy logic based algorithm to detect the edges of an input image by scanning it throughout using a 2*2 pixel window. Also, a Graphical User Interface (GUI) in MATLAB has been designed to aid the loading of the image, and to display the resultant image at different intermediate levels of processing. Threshold level for the image can be set from the slider control of GUI. Fuzzy inference system designed has four inputs, which corresponds to four pixels of instantaneous scanning matrix, one output that tells whether the pixel under consideration is “black”, “white” or “edge” pixel. Rule base comprises of sixteen rules, which classify the target pixel. Algorithm for the noise removal has been implemented at different levels of processing. The resultant image from FIS is subjected to first and second derivative to trace the edges of the image and for their further refinement. The results of the implemented algorithm has been compared with the standard edge detection algorithm such as „Canny‟, „Sobel‟, „Prewit‟ and „Roberts‟. Main feature of the algorithm is that it has been designed by the smallest possible mask i.e. 2*2 unlike 3*3 or bigger masks found in the literature.