Patent ID: 7174030
Filing Date: 2007-02-06
Classification: G06T,H04N

Abstract:
1. An apparatus for embedding a watermark into original picture data, comprising: pattern generating means for generating a fixed two-dimensional bit pattern which remains unchanged when being rotated through one of 90, 180, and 270 degrees; embedding-position deciding means for deciding a two-dimensional watermark-embedding region with respect to the original picture data; random-number generating means for generating random-number data representing a random number; data-storing and calculating means for storing pattern data representing a specified two-dimensional bit pattern which remains unchanged when being rotated through one of 90, 180, and 270 degrees, and for performing given logical operation between the fixed two-dimensional bit pattern and the specified two-dimensional bit pattern to calculate a desired two-dimensional bit pattern for specified bits, the specified bits being among bits in a first portion of the original picture data which corresponds to a first part of the two-dimensional watermark-embedding region; operation means for executing the given logical operation between watermark data and the random-number data; and mixing means for changing the specified bits to represent the desired two-dimensional bit pattern, and for embedding a result of the given logical operation executed by the operation means in a second portion of the original picture data which corresponds to a second part of the two-dimensional watermark-embedding region different from the first part thereof; wherein the fixed two-dimensional bit pattern has a square matrix array of bits with a same number of vertical-line bits and horizontal-line bits, and the specified two-dimensional bit pattern has a square matrix array of bits and is equal in size to the fixed two-dimensional bit pattern, the fixed two-dimensional bit pattern being a first “0” and “1” checkered bit pattern, the specified two-dimensional bit pattern being a second “0” and “1” checkered bit pattern different from the first “0” and “1” checkered bit pattern.