Sketch and texture coding approach to monochrome image coding

Describes a hybrid algorithm for image compression based on independent coding of visually important features in an image. Typical significant features of an image are the sketch (i.e. contours), smooth variations in grey levels between contours and the rapid variation texture. The sketch is often sufficient to represent a familiar image (such as head and shoulders image), while the smooth variations and texture enable it´s appreciation. However, for unfamiliar objects, all three components become indispensable. The coding scheme described is suitable for both classes of images. The paper also describes the implementation of the coding/decoding scheme on a parallel processing computer using the distributed memory, message passing architecture