Reducing Host Interference from Spread Spectrum Watermarking

Abstract

Spread spectrum watermarking (SSW) is one of the most promising watermarking techniques. While SSW is very robust against additive noise, it suffers from an inherent noise. The noise results from host interference on detection of the embedded hidden information. The host interference is one of the main reasons for the relatively low embedding rate in SSW and its reduction is important. In this paper, a new method for use in an SSW detector is proposed to reduce the host interference. The proposed method is based on the law of large numbers and symbol detection of embedded information, instead of bit detection. Since the method is based on the detection of symbols longer than one bit, the detector can employ PN sequences with a larger length, resulting in decrease of the interference. The symbol error rate using this algorithm is calculated employing the maximum a posteriori criterion. Comparison of bit error rates between the modified SSW algorithm and conventional bit detection shows that the modified algorithm is much more robust against the host interference.

Robust audio watermarking based on multi-carrier modulation

“…However, analysis shows that the watermark bit is in complete conflict with the robustness (Cvejic and Seppänen, 2007). The two most important approaches proposed to deal with this issue are, spread spectrum (SS) methods (Kirovski and Malvar, 2002;Sedghi and Suzuki, 2008) that ensure high robustness and quantisation index modulation (QIM)-based schemes (Chen and Wornell, 1999;Vivekananda et al, 2011) that permit a high transmission rate. In our study, we leave behind us QIM methods and focus on SS-based watermarking.…”