Methods of embedding and detecting a watermark into/from a digital image
are disclosed. A method of embedding a watermark in accordance with the
present invention includes generating a predicted image of an original
image by using a linear predictor; generating a difference image by
subtracting said predicted image from said original image or vice versa;
and segmenting said difference image into sub-regions. The method further
includes the steps of calculating a watermark amplitude for each
sub-region or for each pixel of each sub-region; performing a channel
coding process on a set of watermark data bits; calculating a watermark
block for each sub-region by using said encoded data bits, a pseudo
random sequence (PRS) and said watermark amplitude; and embedding said
watermark block into each sub-region by adding said watermark block with
pixel values of each sub-region. As a result of the method described, the
embedded information is robust against any modifications including loss
data compression, filtering, channel noise, cropping, geometrical
transformations, and etc.