Patent ID: 7792323

Claim:
A watermark embedding method that embeds a watermark in a digital image, which watermark is visually imperceptible digital data, the method comprising; a step for determining a degree of local image complexity; and a step for changing complex portions of said image more than low complex degree portions in accordance with a degree of local image complexity, and for generating said degree of local image complexity having a large value for a texture region, and small values for flat regions and edge portions, wherein said step for changing complex portions of said image more than low complex degree portions in accordance with said degree of local image complexity includes: dividing edge/texture component image values obtained by measuring said edge portion and said texture region for a same grade into small blocks, determining the sum of edge/texture component image values in said block for each of the divided blocks and using said sum as a block texture degree index, and up-sampling said block texture degree index and using it as the degree of local image complexity.