Patent ID: 7206451

Claim:
A computer implemented method of processing an array of image data, comprising: applying a predefined family of transform filters to the array of image data so as to generate successive subbands of transform coefficients; encoding the transform coefficients as a set of encoded values, including dividing the encoded values for at least one of the subbands of transform coefficients into two or more portions in accordance with one or more bit plane thresholds, each portion containing a respective distinct range of bit planes of the encoded values for the at least one subband of transform coefficients; and for the at least one subband of transform coefficients, storing a most significant portion of the encoded values in a first contiguous region of an image file, and storing a least significant portion of the encoded values in a second contiguous region of the image file; wherein the applying includes: for at least two of the respective subbands of transform coefficients, generating one or more parameters whose value is indicative of a density of image features in an image represented by the array of image date; classifying the array of image data into one of a predefined set of categories in accordance with the values of the one or more parameters; selecting a set of quantization factors for the array of image data in accordance with the category into which the array of image data has been classified; and scaling the transform coefficients by the set of quantization factors to as to generate a set of quantized transform coefficients for the array of image data.