LOGARITHMIC QUANTIZATION INDEX MODULATION: A PERCEPTUALLY BETTER WAY TO EMBED DATA WITHIN A COVER SIGNAL

摘要

In this paper, a new method for logarithmic Quantization Index Modulation (QIM) is proposed. In this regard a logarithmic function is first applied to the host signal. Then the transformed signal is quantized using uniform quantization as conventional QIM to embed watermark data within. Finally using inverse transform the watermarked signal is obtained. The watermark extraction is performed using minimum distance decoder. The optimum parameter for data embedding with minimum quantization distortion is derived. Also the probability of error is analytically calculated and verified by simulation. Furthermore data hiding using secret key is proposed and the probability of error is obtained. Simulation results show that the proposed method outperforms the conventional QIM in terms of robustness when the perceptual quality of watermarked image for both methods are similar. Moreover, simulation shows that the proposed scheme has outstanding robustness in comparison with a recent quantization based data hiding method.