METHOD AND APPARATUS FOR EMBEDDING AUXILIARY INFORMATION IN A MEDIA SIGNAL

摘要

The invention relates to a system for embedding auxiliary information in a media signal such as an audio visual signal. An apparatus comprises a quantization index modulator ( 103 ) which generates a modified signal by quantization index modulation of the media signal. The modified signal has distortions relative to the media signal which are dependent on the auxiliary information. The apparatus further comprises a perception processor ( 107 ) which generates a perceptual characteristic indicative of a perceptual sensitivity of the media signal to the distortions. The quantization index modulator ( 103 ) and perception processor ( 107 ) are coupled to a compensation processor ( 105 ) which generates an output signal by modifying a strength of the distortions of the modified signal in response to the perceptual characteristic. The invention combines quantization index modulation watermarking with perceptual models to provide an improved trade off between watermark imperceptibility and detection reliability.