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A method and system for watermarking and recovering a watermarked digitized image for subsequent authentication. The digitized image comprises spatial domain data signals reproduced from an original image. A transformer transforms the spatial domain data signals into frequency domain data signals, i

A method and system for watermarking and recovering a watermarked digitized image for subsequent authentication. The digitized image comprises spatial domain data signals reproduced from an original image. A transformer transforms the spatial domain data signals into frequency domain data signals, including respective magnitude and phase data signal components. Information is embedded into the magnitude data signals to develop modified data signals and the modified data signals are converted from the frequency domain to the spatial domain to generate the watermarked digitized image. For recovery, a second transformer transforms the spatial domain data signals comprising the respective original digitized image and watermarked digitized image into respective frequency domain dataset signals. A comparator responsive to the two transformer outputs compares the respective frequency domain dataset signals to identify the watermark and verify the authenticity of the image reproduction.

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1. A method of robust digital image watermarking for embedding a predetermined bit sequence into a digital image, said digital image comprising spatial domain data signals, said method including the steps of:transforming said digital image into frequency domain data signals including respective magn

1. A method of robust digital image watermarking for embedding a predetermined bit sequence into a digital image, said digital image comprising spatial domain data signals, said method including the steps of:transforming said digital image into frequency domain data signals including respective magnitude and phase data signal components;determining a set of contiguous regions in the frequency domain; andembedding said predetermined bit sequence directly into said image frequency domain data signals by mapping bits to well-defined regions in the frequency domain. 2. A method of robust digital image watermarking for embedding a predetermined bit sequence into a digital image, said digital image comprising spatial domain data signals, said method including the steps of:transforming said digital image into frequency domain data signals including respective magnitude and phase data signal components;determining a set of contiguous regions in the frequency domain; andembedding said predetermined bit sequence directly into said image frequency domain data signals by redundantly mapping bits to geometrically well-defined regions in the frequency domain. 3. A method according to claim 2 wherein said embedding step comprises:representing each of said bits as a small variation of the frequency representation of said image over said contiguous region. 4. A method according to claim 2 wherein said embedding step comprises:modulating said frequency domain data signals differentially over a contiguous region of the frequency domain according to said predetermined bit sequence. 5. A method according to claim 4 wherein said modulating step includes:determining a checkerboard-like shaped pattern with said geometrically well-defined regions for said differential modulation comprising 1+/−ε where ε comprises a modulation of relatively small magnitude; andapplying said pattern to the frequency representation of said image. 6. A method according to claim 5 wherein said applying step comprises:multiplying said image data signals by said pattern. 7. A method according to claim 2 wherein said embedding step includes:determining geometric watermark mask signals; andassigning respective bits to respective regions within said frequency domain based upon geometrically masked signals. 8. A method according to claim 7 wherein said determining step includes:creating a watermark capable of carrying watermark information. 9. A method of watermarking a digitized image for subsequent authentication, said digitized image comprising spatial domain data signals and being reproduced from an original image, said method including the steps of:transforming said spatial domain data signals into frequency domain data signals including respective magnitude and phase data signal components;embedding information signals into said magnitude data signals to develop modified data signals by redundantly mapping bits to geometrically well-defined regions in the frequency domain; andconverting said modified data signals from said frequency domain to said spatial domain to generate said watermarked digitized image. 10. A method of watermarking according to claim 9 wherein said step of embedding includes:multiplying said magnitude data signals by watermark mask signals. 11. A method of watermarking according to claim 9 wherein said step of embedding includes:adding watermark mask data signals to said magnitude data signals. 12. A method of watermarking according to claim 9 wherein said information signals comprise small changes to predetermined areas of said magnitude data to maintain visual imperceptibility of said watermark. 13. A method of watermarking according to claim 9 wherein said step of embedding includes:placing said information signals into low frequency regions of said frequency domain to maintain watermark survival following image modifications. 14. A method of watermarking according to claim 9 wherein said step of embedding includes:compensating f or expected image modifications to maintain watermark survivability. 15. A watermarking apparatus for tagging a digitized image for subsequent authentication, said digitized image comprising spatial domain data signals and being reproduced from an original image, said apparatus including:a transformer, said transformer operating to transform said spatial domain data signals into frequency domain data signals including respective magnitude and phase data signal components, by redundantly mapping bits to geometrically well-defined regions in the frequency domain;a processor disposed to receive the output of said transformer, said processor being operative to embed information signals into said magnitude data signals to develop modified data signals; anda converter located to receive the output of said processor, said converter operative to convert said modified data signals from said frequency domain to said spatial domain to generate said watermarked digitized image. 16. A watermarking apparatus according to claim 15 wherein said processor includes a multiplier. 17. A watermarking apparatus according to claim 15 wherein said processor includes an adder. 18. A method of recovering a watermark from a tagged digitized image comprising a reproduction of an original digitized image, said tagged digitized image and said original digitized image both comprising spatial domain dataset signals, said method including the steps of:transforming said spatial domain data set signals comprising said respective original and tagged image signals into respective frequency domain dataset signals by redundantly mapping bits to geometrically well-defined regions in the frequency domain; andcomparing said respective frequency domain dataset signals to identify said watermark and verify the authenticity of said image reproduction. 19. A method of recovering a watermark according to claim 18 wherein said comparing step includes:taking the ratios of various local averages or functions of said respective dataset signals. 20. A method of recovering a watermark according to claim 18 wherein said comparing step includes:taking the difference between said respective frequency domain dataset signals to identify said watermark. 21. A method of recovering a watermark according to claim 18 wherein said comparing step includes:estimating a filter factor. 22. A method of recovering a watermark according to claim 18 wherein said transforming step includes:taking the fourier transform of said respective spatial dataset signals. 23. A method of recovering a watermark according to claim 21 wherein said step of determining a filter factor includes:reserving a selected portion of said frequency domain;forming an estimate of said filter factor; andextrapolating said estimate over said frequency domain. 24. A method of recovering a watermark according to claim 21 wherein said determining step includes:identifying contiguous regions in said frequency domain; anddecoding embedded watermark information signals over said identified region. 25. A method of watermarking a digitized image for subsequent authentication, said digitized image comprising spatial domain data signals and being reproduced from an original image, said method including the steps of:transforming said spatial domain data signals into frequency domain data signals including respective magnitude and phase data signal components;embedding information signals into said magnitude data signals to develop modified data signals; andconverting said modified data signals from said frequency domain to said spatial domain to generate said watermarked digitized image. 26. A watermarking apparatus for tagging a digitized image for subsequent authentication, said digitized image comprising spatial domain data signals and being reproduced from an original image, said apparatus including:a transformer, said transformer operating to transform said spatial domain data signals into frequency domain data signals, including re spective magnitude and phase data signal components;a processor disposed to receive the output of said transformer, said processor being operative to embed information signals into said magnitude data signals to develop modified data signals; anda converter located to receive the output of said processor, said converter operative to convert said modified data signals from said frequency domain to said spatial domain to generate said watermarked digitized image. 27. A method of recovering a watermark from a tagged digitized image comprising a reproduction of an original digitized image, said tagged digitized image and said original digitized image both comprising spatial domain dataset signals, said method including the steps of:transforming said spatial domain data set signals comprising said respective original and tagged image signals into respective frequency domain dataset signals; andcomparing said respective frequency domain dataset signals to identify said watermark and verify the authenticity of said image reproduction. 28. A watermark recovery apparatus for authenticating a tagged digitized image comprising a reproduction of an original image, said respective images comprising spatial domain dataset signals, said apparatus including:a transformer, said transformer operative to transform said spatial domain data signals comprising said respective images into respective frequency domain dataset signals; anda comparator, said comparator being responsive to said transformer to compare said respective frequency domain dataset signals to identify said watermark and verify the authenticity of said image reproduction. 29. A digitized image authentication system for implanting and detecting watermark information in a digitized reproduction of an image, said digitized image comprising spatial domain data signals and being reproduced from an original image, said system including:a watermarking apparatus for tagging said digitized image signals, said apparatus including:a transformer located to receive said spatial domain data signals, said transformer operative to transform said spatial domain data signals into frequency domain data signals including respective magnitude and phase data signal components;a processor disposed at the output of said transformer, said processor being operative to embed information into said magnitude data signals to develop modified data signals;a converter positioned to receive the output of said processor, said converter being operative to convert said modified data signals from said frequency domain to said spatial domain to generate said watermarked digitized image signals; anda watermark recovery apparatus for authenticating said tagged digitized image, said recovery apparatus including:a transformer located to receive said spatial domain data signals comprising said respective images, said transformer being operative to transform said spatial domain data signals into respective frequency domain dataset signals; anda comparator receiving said respective frequency dataset signals from said transformer, said comparator being operative to compare said respective frequency domain dataset signals to identify said watermark and verify the authenticity of said image reproduction. 30. A watermark recovery apparatus for authenticating a tagged digitized image comprising a reproduction of an original image, said respective images comprising spatial domain dataset signals, said apparatus including:a transformer, said transformer operative to transform said spatial domain data signals comprising said respective images into respective frequency domain dataset signals by redundantly mapping bits to geometrically well-defined regions in the frequency domain; anda comparator, said comparator being responsive to said transformer to compare said respective frequency domain dataset signals to identify said watermark and verify the authenticity of said image reproduction. 31. A digitized image authentication system for implanting and detecting watermark information in a digitized reproduction of an image, said digitized image comprising spatial domain data signals and being reproduced from an original image, said system including:a watermarking apparatus for tagging said digitized image signals, said apparatus includinga transformer located to receive said spatial domain data signals, said transformer operative to transform said spatial domain data signals into frequency domain data signals including respective magnitude and phase data signal components;a processor disposed at the output of said transformer, said processor being operative to embed information into said magnitude data signals to develop modified data signals by redundantly mapping bits to geometrically well-defined regions in the frequency domain;a converter positioned to receive the output of said processor, said converter being operative to convert said modified data signals from said frequency domain to said spatial domain to generate said watermarked digitized image signals; anda watermark recovery apparatus for authenticating said tagged digitized image, said recovery apparatus including:a transformer located to receive said spatial domain data signals comprising said respective images, said transformer being operative to transform said spatial domain data signals into respective frequency domain dataset signals; anda comparator receiving said respective frequency dataset signals from said transformer, said comparator being operative to compare said respective frequency domain dataset signals to identify said watermark and verify the authenticity of said image reproduction. 32. A method according to claim 4, wherein the modulating step includes:placing said bits of the predetermined bit sequence into lower frequencies of said frequency domain comprising of a sequence of concentric rings located between radii r i and r 1+i . 33. A method according to claim 32, wherein said bits, b 1 , b 2 . . . , b N , of the predetermined bit sequence are placed into lower frequencies of said sequence of concentric rings in accordance with the following formula: W M ( u,v )=1+ε(−1) b for {square root over ( u 2 +v 2 )}ε[r i ,r i+1 ). 34. A method according to claim 2, wherein said predetermined bit sequence is absent from a DC component of said digital image.