Patent ID: 6240214
Filing Date: 2001-05-29
Classification: G06T,H04N

Abstract:
A method for encoding a binary shape signal including a plurality of pixels, each pixel having one of two different binary values, comprising the steps of:(a) detecting distribution characteristics between the pixels in the binary shape signal to thereby produce a first or a second selection signal;(b) in response to the first selection signal, encoding the binary shape signal by using a first context-based arithmetic encoding technique for processing the binary shape signal on a pixel-by-pixel basis to thereby generate the encoded binary shape signal; and(c) under the control of the second selection signal, encoding the binary shape signal by using a second context-based arithmetic encoding technique for processing the binary shape signal on a subblock-by-subblock basis to thereby produce the encoded binary shape signal, wherein the binary shape signal is partitioned into a multiplicity of subblocks and the number of pixels in each subblock is smaller than the number of pixels in the binary shape signal and larger than 1,wherein the step (a) includes the steps of:(a1) counting the number of pairs of adjacent pixels in the binary shape signal whose binary values are different from each other;(a2) comparing the number of pairs with a predetermined threshold value; and(a3) producing the first or the second selection signal in conformity with the comparison result, wherein the first selection signal is generated if the number of the pairs is greater than the predetermined threshold value, and the second selection signal is produced if otherwise.