The Laplacian operator, written ∇2, is used in image processing. It is the second differential of the itensity of the image. In areas with slower constant changes in intensity the Laplacian is small, but where thsi changes, typically at the boundaries of objects, it is large. It is therefore useful as part of {[edge detection}} algorithms. The theoretical Laplacian is based on a functions of continuous variables, but this approximated on the pixels of a real image using a linear operator.
Defined on pages 253, 253
Used on page 253
Approximations to the Laplacian
Using the Laplacian