METHOD AND APPARATUS FOR VISUAL LOSSLESS IMAGE SYNTACTIC ENCODING

A visual lossless encoder for processing a video frame prior to compression by a video encoder includes a threshold unit, a filter unit, an association unit and an altering unit. The threshold unit identifies a plurality of visual perception threshold levels to be associated with the pixels of the video frame, wherein the threshold levels define contrast levels above which a human eye can distinguish a pixel from among its neighboring pixels of the frame. The filter unit divides the video frame into portions having different detail dimensions. The association unit utilizes the threshold levels and the detail dimensions to associate the pixels of the video frame into subclasses. Each subclass includes pixels related to the same detail and which generally cannot be distinguished from each other. The altering unit alters the intensity of each pixel of the video frame according to its subclass.