An edge enhancement system, including a selective edge controller for
determining one or more properties of an edge of image data, and for
generating one or more weighting factors on the basis of properties of
the edge; and a scaling module for scaling an edge enhancement signal by
the weighting factors to control the degree of edge enhancement. The
image data may represent a still or moving (i.e., video) image. A max-min
search circuit determines maximum and minimum turning points closest to
the center of the data processing window and that are located on opposing
sides of the window, to determine values and locations of maximum and
minimum pixels of the edge. An edge-directed pre-filtering circuit
reduces the amplification of edge fuzziness by smoothing close the edges
vertical prior to enhancement. An aliasing protection circuit reduces the
visibility of saw-tooth defects on predominantly horizontal diagonal
edges.