Novel Quantization Watermarking Based on Random Angle Modulation

This paper presents a novel quantization based watermarking scheme. Watermark embedding is performed through modulating the angle between the host vector and a random vector with dither modulation technique. The watermarked signal with the modulated angle is derived in the sense of minimizing the embedding distortion. The proposed scheme is theoretically invariant to valumetric scaling and can resist stronger noise than the well-known spread transform dither modulation. Numerical simulations on real images show that it achieves the good imperceptibility and strong robustness against a wide range of attacks.