An adaptive bistable system based detector and its application in watermark extraction

In this paper, we explore the bistable system (BS) based detector for a binary pulse amplitude modulated (PAM) signal embedded in non-Gaussian noise. Through the example of BS based watermark extraction, we show that a reliable performance cannot be obtained if the BS parameters are determined by tuning technique. The key observation is that the BS parameters are not sensitive to the noise pdf but the noise variance and the signal amplitude. That makes it possible to determine the BS parameters in advance and an adaptive BS can be constructed. Experimental results show that the performance of the proposed adaptive BS detector is stable and is superior to the existing BS based watermark schemes and Gaussian based maximum likelihood (ML) detector.