Slide 1 Joe O’Ruanaidh Siemens Corporate Research Princeton, NJ Digital Watermarking: How it works! SIGGRAPH’99 Panel Friday 13 August 2:15pm - 4:00pm Gabriella Csurka CUI, University of Geneva Switzerland

Slide 2 Agenda Some Examples: almost but not quite! –Glyphs –Easter Eggs –Money Dots Spread Spectrum Image Watermarking Video Watermarking Security Conclusions

Slide 3 Goals Context: distribution of documents over Internet Goal: copyright enforcement image video audio text Framework: security architecture (e.g. DCT Switzerland, Fraunhof Institute); public and private watermark.

Slide 4 The Holy Grail No original image! –watermark resistant to e.g.:photometric transformations, scanning; JPEG, MPEG compression; geometric transformations: cropping, translation, rotation, scaling, aspect ratio change, flip, general linear or affine transformation; regular removal of rows/columns or videoframes, shearing –video frame rate change (temporal scaling); –cryptographic attacks.

Slide 5 Spread Spectrum Looks like noise! Technically it’s a symmetric key cryptosystem Very very robust.

Slide 6 Original Images

Slide 7 Transformations of images

Slide 8 Basic approach spread-spectrum sequence inserted in transform domain; template: key-based grid to recover geometric transformations, inserted and detected in transform domain

Slide 9 Template: key-based grid to recover aspect ratio and frame-rate changes, Inserted in transform domain Detected in log-log-log mapping of transform domain; Video watermarking: frame by frame or as 3D object

Slide 10 Detecting a Watermark Wrong Key No watermark there -20dB SNR -40dB SNR

Slide 11 Review We need a fully integrated and secure system. Complete solution involves aspects of: –Cryptography –Communications –Spatial Transformations –Statistical Decision Theory