Presentation of Information Synchronized with the Audio Signal Reproduced by Loudspeakers using an AM-based Watermark

Reproducing stego audio signal via a loudspeaker and detecting embedded data from a recorded sound from a microphone are challenging with respect to the application of data hiding. A watermarking technique using subband amplitude modulation was applied to a system that displays text information synchronously with the watermarked audio signal transmitted in the air. The robustness of the system was evaluated by a computer simulation in terms of the correct rate of data transmission under reverberant and noisy conditions. The results showed that the performance of detection and the temporal precision of synchronization were sufficiently high. Objective measurement of the watermarked audio quality using the PEAQ method revealed that the mean objective difference grade obtained from 100 watermarked music samples exhibited an intermediate value between the mean ODGs of 96-kbps and 128-kbps MP3 encoded music samples.