Audio watermarking for monitoring and copy protection

Based on existing technology used in image and video wa-termarking, we have developed a robust audio watermark-ing technique. The embedding algorithm operates in fre-quency domain, where the magnitudes of the Fourier co-efficients are slightly modified. In the temporal domain, an additional scale parameter and gain function are neces-sary to refine the watermark and achieve perceptual trans-parency. Watermark detection relies on the Symmetrical Phase Only Matched Filtering (SPOMF) cross-correlation approach. Not only the presence of a watermark, but also its cyclic shift is detected. This shift supports a multi-bit payload for one particular watermark sequence. The water-marking technology proved to be very robust o a large num-ber of signal processing "attacks " such as MP3 (64 kb/s), all-pass filtering, echo addition, time-scale modification, re-sampling, noise addition, etc. It is expected that this ap-proach may contribute in a wide variety of existing (e.g. monitoring and copy protection) and future applications