Patent Document ID: 20040032967
Application ID: 10436014
Patent Status: 0

Claim One:
1. A method for inserting watermark information B(b 0,b 1,...,b W−1, b w &egr;&lcub;0,1&rcub;, 0&lE;w&lE;W−1) for each input vector x t (0&lE;t&lE;T−1) of a vector-quantized source image using codeword grouping, the method comprising: a step 1 - 1 of generating three groups G −1, G 0 and G 1 that satisfy relationships C&equals;G −1 ∪G 0 ∪G 1 and G −1 ∩G 0 &equals;G 0 ∩G 1 &equals;G −1 ∩G 1 &equals;&phgr; and a condition that a codeword c j corresponding to a codeword c i belonging to the group G 0 (or G 1 ) must belong to the group G 1 (or G 0 ), for the whole set C of codewords constructing a codebook; a step 1 - 2 of initializing variables t and w to be processed; a step 1 - 3 of selecting one bit b w of the watermark information B; a step 1 - 4 of selecting a codeword c i that is the closest to x t from the codebook; a step 1 - 5 of judging a group G P including the selected c i, incrementing t by 1 when P is −1, and returning to the step 1 - 4 ; a step 1 - 6 of allocating the codeword c i without any change when the integer value of the current watermark bit b w is identical to P and allocating the codeword c j corresponding to c i when it is not identical to P, in the case where P is judged to be 0 or 1 from the judgement of the group G P including the selected c i ; and a step 1 - 7 of finishing processing of the watermark when the watermark information B has been completely processed, and respectively incrementing the variables w and t by 1 when it has not been completely processed and then returning to the step 1 - 3.