Patent ID: 6785423
Filing Date: 2004-08-31
Classification: H04N

Abstract:
A method for producing a compressed digital image from an input digital image, wherein the compressed digital image is organized into layers having information that can be extracted in accordance with different desired viewing conditions and resolutions, comprising the steps of:(a) decomposing the input digital image to produce a plurality of subbands, each subband having a plurality of subband coefficients; (b) quantizing the plurality of subband coefficients of each subband of the decomposed input digital image to produce a quantized output value for each subband coefficient of each subband; (c) forming at least one bit-plane from the quantized output values of subband coefficients of each subband; (d) entropy encoding each bit-plane of each subband in at least one pass to produce a compressed bit-stream corresponding to each pass, wherein each subband is entropy encoded independently of the other subbands; (e) providing a visual quality table that specifies a number of expected visual quality levels by providing selectable viewing conditions and resolutions for each expected visual quality level; (f) identifying a minimal set of passes and their corresponding compressed bit-streams that are necessary to satisfy the expected visual quality levels provided in the visual quality table, whereby a user can select different desired viewing conditions arid resolutions for each compressed image; and (g) ordering the compressed bit-streams corresponding to passes into layers from the lowest expected visual quality level to the highest expected visual quality level specified in the visual quality table to produce a compressed digital image, wherein each layer includes the passes and their corresponding compressed bit-streams from the identified minimal set corresponding to the expected visual quality level that have not been included in any lower visual quality layers.