Spread-spectrum audio watermark robust against pitch-scale modification

A new digital audio watermarking for copyright protection is described in this paper. The watermark is embedded in the time domain by taking use of spread-spectrum technique and exploiting the hearing thresholds in the psychoacoustic model. The scheme of detection is based on high-pass filtering and correlation. The decision threshold is adaptively determined according to the statistical distribution of correlation values. Besides, the post-processing technique is introduced for resisting time-scale modification. Experimental results show that the proposed watermarking scheme is high robust to almost any attacks, including cropping, low-pass filtering, noise addition, MP3 compression, sampling rate changing, requantization, time-scale modification, and pitch-scale modification.