Analysis of quantization-based watermarking

Necessary and sufficient conditions for robustness to the public watermarking algorithm and its upper limit of attack-resistance energy were given, which supplied a gap that there was no exact upper limit in the attack-resistance evaluation. Then it analysed change amplitude of the carrier’s coefficients and range of the added pattern in fidelity-fixed optimization, which partly solved the problem of protecting watermarking during fidelity-fixed optimization, and pointed out the difference between quantization encoding and common variable information payload and the reasons of difference in information capacity calculation. After that, a vision optimized embedding algorithm and other ten equivalent ones were constructed. And then a quantization watermarking scheme with twice attack-resistance of mod-based embedding algorithms was proposed in the same carrier altered range, which overcomed the disadvantage of low attack-resistance to Mod-based watermarking schemes. Also, it constructed gray level embedding schemes which avoided the transformation from gray value to binary. Finally, the experimental results support the theoretic analysis and presented schemes.