A computer-based technique for detecting edges in gray level digital
images employs fuzzy reasoning to analyze whether each pixel in an image
is likely on an edge. The image is analyzed on a pixel-by-pixel basis by
analyzing gradient levels of pixels in a square window surrounding the
pixel being analyzed. An edge path passing through the pixel having the
greatest intensity gradient is used as input to a fuzzy membership
function, which employs fuzzy singletons and inference rules to assigns a
new gray level value to the pixel that is related to the pixel's edginess
degree.