Patent ID: 6668095
Filing Date: 2003-12-23
Classification: H04N

Abstract:
A method for compressing an image presented as image data in the form of a pixel array comprising:transforming a plurality of pixel blocks to transform coefficients in a frequency domain, wherein the pixel blocks are rectangular, non-overlapping, and the plurality of pixel blocks covers the pixel array, and wherein the transform coefficients represent each pixel block and include a zero frequency transform coefficient, one or more selected low frequency transform coefficients, and remaining transform coefficients, predicting for each pixel block the selected low frequency transform coefficients from a linear combination of the zero frequency transform coefficient of the pixel block and of the zero frequency transform coefficients of pixel blocks orthogonally adjacent to the pixel block, subtracting for each pixel block the predicted selected low frequency transform coefficients from the selected low frequency transform coefficients to form difference transform coefficients, quantizing for each pixel block the difference coefficients and the remaining transform coefficients, and representing the image by compressed image data comprising the zero frequency transform coefficient, the quantized difference coefficients, and the quantized remaining coefficients for each of the plurality of pixel blocks.