WATERMARK DETECTION

摘要

Disclosed is a method and arrangement for detecting a watermark in a suspect signal. Usually, a watermark is embedded by adding a watermark pattern w to a signal p with a given embedding strength s ("additive embedding": q=p+sw). The embedded watermark is then detected by correlating (2, 3) it with the suspect signal. Recently, "multiplicative embedding" has been proposed (q=p(1+sw)). In accordance with the invention, multiplicatively embedded watermarks are detected by raising (1) the signal to a power beta prior to correlating it with the watermark. The power beta may be fixed (e.g. beta =2) or derived from a statistical analysis (5) of the signal.