Edge detection and processing

Normal classes:

EdgeSobelC	Sobel edge detection engine.
EdgeDericheC	Deriche edge filter.
EdgeNonMaxSuppressionC	Linear non-maximal suppression.
EdgelC	Edge Location, Direction and Magniture information.
EdgeDetectorC	Edge detector.

Normal functions:

operator <<(ostream &,const EdgelC &)	Write to a stream.
operator >>(istream &,EdgelC &)	Read from a stream.
SobelGradient3(const Array2dC &,const Index2dC &)	Measure the gradient at a point in an image using a 3x3 Sobel operator.