EMBEDDING AND DETECTING A WATERMARK IN AN INFORMATION SIGNAL

摘要

A known method of watermarking an information signal is based on extraction of salient points (21) of the signal (e.g. zero crossings in audio, edges of an image) and "warping" (24) said salient points towards a given watermark pattern (W). One step in the embedding and detection process is determining (22) whether or not salient points lie "on" or "off" the watermark. This is a hard decision. It is now proposed to extend salient points to salient "regions" (25). This turns the step of matching (22) into a soft decision, which is less vulnerable to signal processing. The robustness of the embedded watermark is thereby improved.