A Robust Audio Watermarking System for Acoustic Channels

Digital audio watermarking is one of the many technologies which evolved in response to the recent fast expansion in the area of digital information transmission and multimedia. In fact, the possibility to hide information in an audio signal has many applications, such as protection of intellectual property, tamper proofing, and copy and access control. This article presents an innovative method for watermark embedding in the time-frequency domain for broadcast monitoring and auditing. In particular, the proposed system involves a watermarked audio signal which is played back by a loudspeaker and picked up by a microphone mounted on a mobile device. The system is built to be used in an enclosed environment such as a room and is therefore designed to be robust against various impairments such as reverberation, microphone self-noise, and movement. The system robustness is confirmed by performance evaluations, whereas its inaudibility is verified by subjective listening tests.