Patent ID: 6173080
Filing Date: 2001-01-09
Classification: G06F,G06T

Abstract:
A discrete cosine transform (DCT) coefficient prediction and encoding method, comprising the steps of:(a) dividing a block of coefficients, representing image pixels in a DCT domain, into two regions, a predicted region including a vertical or a horizontal component area, and a non-predicted remaining region for which coefficients are not predicted;(b) scanning said vertical or horizontal component area of quantized AC coefficients in the DCT domain to obtain location information of a current block, which indicates whether AC coefficients are zero or not;(c) excluding, from prediction of a DC coefficient and AC coefficients of the current block from quantized DC and AC coefficients of adjacent blocks in the predicted region of the current block, all zero AC coefficients in said current block based on said location information;(d) predicting a DC coefficient and only non-zero AC coefficients of the current block from quantized DC and AC coefficients of the adjacent blocks in the predicted region of the current block; and(e) encoding the absolute difference between the DC coefficient of the current block and those of the adjacent blocks, and the absolute differences between the non-zero AC coefficients in the vertical or horizontal area of the current block, and those of the adjacent blocks, using the location information and the prediction coefficients, and applying a zig-zag scanning to the remaining non-predicted AC coefficients for encoding.