Selective correlation detector for additive spread spectrum watermarking in transform domain

As an improvement on additive spread spectrum (ASS) watermarking, this paper proposes the selective correlation detector (SCD), which performs correlation detection on a portion rather than the whole block of the signal. The portion is determined based on the watermark-to-cover signal power ratio (WCR) and the estimated variance of the correlation. A similar improvement has been obtained by improved spread spectrum (ISS) watermarking [6] (Malvar and Florencio, 2003), but we show that a better performance can be achieved by combining both algorithms. Experiments with or without a psychoacoustic model are conducted on several audio signals, and confirm the improvements by the SCD and by the combined ISS and SCD.