Oblivious Image Watermarking Robust against Scaling and Geometric Distortions

Watermarking stays the main technical safeguard of electronic copyright. This paper presents the first public-domain oblivious watermarking scheme for images which survives scaling and geometric distortion attacks. Previous proposals are either proprietary, nonoblivious or require scaling or geometric distortion to be undone prior to mark recovery, which may not be practical in oblivious watermarking. The new scheme uses a tile-based embedding technique that allows mark recovery from a scaled or geometrically distorted watermarked image. Other properties of the scheme presented here are that it operates on the spatial domain, supports multiple marking and does not require previous knowledge of the embedded copyright sequence. The latter property makes the proposed watermarking suitable for fingerprinting purposes.