Patent ID: 7197162

Claim:
An image processing apparatus which multiplexes noise on a multilevel image data containing at least a luminance component as a main component, thereby embedding visible additional information with a noise-multiplexed distribution, comprising: input means for inputting, as the additional information, information representing whether or not to multiplex noise for each pixel; determination means for determining on the basis of the additional information whether a pixel of interest in the multilevel image data is located at a position where noise is to be multiplexed; luminance value calculation means for, when said determination means determines that the pixel of interest is located at the position where noise is to be multiplexed, calculating an addition luminance value to be added to the pixel of interest on the basis of a luminance value of a neighboring region near the pixel of interest; and addition means for adding the calculated addition luminance value to a luminance value of the pixel of interest.