Patent ID: 6721439
Filing Date: 2004-04-13
Classification: G06T,H04N

Abstract:
A method of watermarking digital image data having an associated domain representation comprising the steps of:encoding watermark data using an error correcting code to generate encoded watermark data; transforming the digital image data from a spatial domain representation into a transform domain representation; embedding the encoded watermark data into a first sub-set of elements of a domain representation of the image to generate an embedded sub-set of the domain representation using scaled bin encoding by scaling each element of the sub-set of the domain representation of the image with a scaling parameter which is representative of the statistics of the image data, an expected noise level and an allowed distortion model; mapping each scaled element to one of a pair of skewed discrete mappings dependent on the logic state of a corresponding encoded watermark data bit to be embedded into each scaled element; obtaining a difference between each scaled element from its corresponding original element; and adding the difference to its corresponding original element to obtain each watermark embedded element; combining the embedded sub-set of elements with the remaining unembedded portion of elements of the domain representation of the image to generate a watermark embedded domain representation of the image; inversely transforming the watermark embedded domain representation of the image to generate a spatial domain representation of the watermarked digital image which includes the digital image data and the watermark data.