Watermarking
Watermarking. Matt Elliott Brian Schuette. Overview. Goals Methods Comparison Attacks References. Watermark Goals Robust Invisible Recovery. Project Goals Watermark Types Fragile Robust Techniques Frequency Domain Spatial domain. Goals. Bit-Plane Slicing. Spatial Domain
Watermarking
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Presentation Transcript
Watermarking Matt Elliott Brian Schuette
Overview • Goals • Methods • Comparison • Attacks • References
Watermark Goals Robust Invisible Recovery Project Goals Watermark Types Fragile Robust Techniques Frequency Domain Spatial domain Goals
Bit-Plane Slicing • Spatial Domain • LSB contains watermark • Simple detection • Many options • Image blocks • Encode Text • Specific Areas
seed random vector generator Original image marked image wmk N largest coeff. IDCT & normalize 2D DCT sort v’=v (1+ w) other coeff. Cox Method • Frequency Domain • Transformation • AC Coefficients • Sorted by size • Largest 1000 selected • Psuedo-random watermark embedded • Reverse transformation
Comparison • Fragile Watermark • Very susceptible to attack • Used for tampering detection • Robust Watermark • Resistant to tampering • Used with public images • Provides proof of ownership
Methods of Attack • Scaling • Cropping • JPEG • Print/Xerox
References • ECE 738 Advanced Digital Image Processing • Professor Hu • Wikipedia • Digital Image Processing, Gonzalez and Woods • I. Cox, J. Kilian, T. Leighton, T. Shamoon: “Secure Spread Spectrum Watermarking for Multimedia'', IEEE Transaction on Image Processing, vol.6, no.12, pp.1673-1687, 1997.