Patent ID: 6807308
Filing Date: 2004-10-19
Classification: G06F,G06T,G09G,H04N

Abstract:
A method of processing an array of image data representing an image, comprising:processing tiles of the image data in a predefined order, the tiles comprising nonoverlapping portions of the image data, so as to generate processed image data; and storing the processed image data as a data image file; the processing of each tile of image data comprising: applying a predefined family of transform filters to the tile of image data so as to generate successive sets of transform coefficients; each respective set of transform coefficients corresponding to a group of one or more spatial frequency subbands of the image; wherein each subband group is generated by application of a distinct respective transform layer of the predefined family of transform filters; for at least two of the respective subband groups, each group having a distinct dimension, generating one or more parameters whose value is indicative of density of image features in the tile; classifying the tile into one of a predefined set of categories by comparing the one or more parameters with a plurality of predetermined thresholds; selecting a set of quantization factors for each respective tile in accordance with the category into which the tile has been classified; and scaling the transform coefficients of the tile by the set of quantization factors so as to generate a set of quantized transform coefficients for the tile.