Reversible Watermarking for Digital Audio Based on Cochlear Delay Characteristics

There have recently been serious social issues involved in multimedia signal processing such as digital rights management, secure authentication, malicious attacks, and tampering with digital audio/speech signals. Reversible watermarking is a technique that enables these signals to be authenticated and then restored to their original signals by removing watermarks from them. We previously proposed an inaudible digital-audio watermarking approach based on cochlear delay (CD). We investigated how the proposed approach could be developed as reversible watermarking by considering blind detection for inaudible watermarks and the reversibility of audio watermarking. We evaluated inaudible and reversible watermarking with the proposed approach by carrying out three objective tests (PEAQ, LSD, and bit-detection or SNR). The results revealed that reversible watermarking based on CD could be accomplished.