Method of Digital-Audio Watermarking Based on Cochlear Delay Characteristics

Abstract

This chapter introduces a state-of-the-art scheme of non-blind digital-audio watermarking, based on the properties of the human cochlear. It is based on the concept of embedding inaudible watermarks into an original sound by controlling its phase characteristics in relation to the characteristics of Cochlear Delay (CD). Inaudible watermarks are embedded into original signals by applying Infinite Impulse Response (IIR) all-pass filters with CDs and they are then extracted from the phase difference between the original and watermarked sounds. The results obtained from objective and subjective evaluations and robustness tests revealed that the CD-based approach is considerably more effective in satisfying the requirements for non-blind inaudible watermarking. Embedding limitations with the CD-based approach were investigated with various evaluations. These results also revealed that embedding limitations with the CD-based approach could be improved by using parallel, cascade, and composite architectures for the CD filters.