This LoG filter is also known as the Mexican hat filter, since it has the shape of
a positive peak in a negative dish. It is separable in the x and y directions and
thus can be implemented efficiently. The parameter s controls the width of the
peak, which is related to the amount of smoothing. The edge positions can
be determined by the zero-crossings in the LoG-filtered image.
9.3.5 Boundary Finding Based on Edge
Detection and Linking
As discussed earlier, edges are closely associated with the boundaries of objects
in an image. Pixels exhibiting the required characteristics are known as edge
points. Edge points can be detected and used to establish the boundaries. We can
examine each of these pixels and its immediate neighborhood to determine if it
is, ...