| 摘要 |
PROBLEM TO BE SOLVED: To extract an electronic watermark at a high speed even from the image, being partially cut out, such as a limited color image whose embedding place is limited to prohibit embedding in an arbitrary place, where an electronic watermark is embedded. SOLUTION: An original image is divided into blocks of pixels of exponentiation of 2, and an electronic watermark is separately embedded for each block. An embedded value is determined to be a boundary position collation data or an arbitrary information, depending on combination of boundary of exponentiation of 2 for the coordinate value (X, Y) of the place where the electronic watermark can be embedded. In order to extract the electronic watermark information contained in a block from the partial image cut out into an arbitrary size (including a whole one block or more) at an arbitrary place, the boundary position is calculated in the order from a low order layer side to high order layer side (from first power to second power, third power... of 2) using the boundary position collation data, decreasing the number of collation for faster speed. COPYRIGHT: (C)2007,JPO&INPIT
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