Quantization index modulation: a class of provably good methods for digital watermarking and information embedding

We consider the problem of embedding one signal (e.g., a digital watermark), within another "host" signal to form a third, "composite" signal. The goal is to achieve efficient rate-distortion-robustness trade-offs. We introduce a new class of embedding methods called distortion-compensated quantization index modulation. In several different contexts involving both intentional and unintentional attacks, capacity-achieving methods exist within this class, while in other contexts these methods achieve provably better rate-distortion-robustness performance than previously proposed spread-spectrum and generalized low-bit(s) modulation methods.