Abstract: An image processing system encodes a natural image into a segmented or mosaic image having well-defined edges and a residual image. The segmented image is encoded using a lossless encoding technique while the residual image is encoded using a lossy technique. This encoded image may be recorded on a video tape such that the segmented image may be recovered in picture-in-shuttle modes such as fast forward and fast rewind. In addition, the recorded image may be decoded and reencoded through several generational levels without experiencing significant degradation in perceived image quality. The segmented image is produced by an encoder which employs a multi-scale edge finder that is able to resolve transitions occurring over two, four and eight pixels into an edge located between two pixels.

Abstract: An edge finder for an image processing system locates edges in a digitized image over several different ranges of pixel values and assigns, to each pixel value an edge characteristic value which represents a minimum edge value for the pixel in the image. The exemplary edge finder that is able to resolve transitions occurring between two pixels or over groups of four or eight pixels to determine whether an edge should be defined between the original two pixels. The edge finder simultaneously examines four edges in two dimensions to determine the edgeness value for each pixel in the digitized image.