An Audio Watermarking Method Using Tones of Diatonic Chord

For audio signals, the sound quality of the stego signal should not deteriorate as much as host signal. With current methods, high sound quality means that the difference between the host and stego signals is small. We proposed a method with which high sound quality means that the sound quality of the stego signal is maintained as music even if another sound, except for host signal, is perceived. Accordingly, we focused on the counterpoint of music theory. A watermark signal is added in consonance to the tones of the host signal based on counterpoint. For this study, we used a diatonic chord as consonance. We also used a sound with an instrumental timbre as the watermark signal. The sound quality of the stego signal does not produce an unpleasant feeling to the listener even if the watermark signal is perceived.