DIGITAL IMAGE WATERMARKING SYSTEM AND METHOD

摘要

A method of producing a printed image comprising digital information embedded in a digital cover image. The method involves obtaining a frequency domain representation of the digital cover image, partitioning the frequency domain representation into blocks and selecting a sub-set of the frequency components of each block. A respective bit of the digital information is embedded in a respective one of the sub-sets by changing the polarity of the value of at least one of the respective frequency coefficients in the sub-set to create a modified block. The modified blocks are used to create a spatial domain representation of the digital cover image in which the digital information is embedded. The modified spatial domain representation of the digital cover image is then printed. The method is robust against distortion errors that can be introduced during print and scan operations and so the embedded digital information can readily be detected when the printed image is subsequently scanned.