Edge detection is an important task in image analysis, and it plays important role in computer vision and medical imaging applications. In this paper, fuzzy rule based image processing algorithm has been developed for detecting the edges in the image, based on the changes in the gray values. Gray values of the image are taken as the input of the fuzzy system and a floating mask of 3×3 is applied on the image to detect edge pixel using the predetermined fuzzy rules. The robustness of the proposed method is analyzed, compared and evaluated using the image quality assessment metrics such as signal to noise ratio(SNR), peak signal to noise ratio (PSNR) and root mean square (RMSE) and the results are presented. © Research India Publications.