【摘要】 基于人类视觉特性(VHS),提出了一种新的量化水印方案。水印信息以量化方式嵌入在二层变换系数上,这些二层变换系数是由小波系数乘以不同权重、混洗后再进行离散余弦变换生成的。其中权值根据视觉特性确定,使得水印信号在高、低频部分的能量合理分配以保证较小的视觉失真。这种方法在无视觉失真的条件下可以保证较好的嵌入量和稳键性。定量地分析了信息量、隐蔽性和稳健性三者的关系,并用模拟实验验证了这些结果。更多还原

【Abstract】 Multibit watermarks can be embedded into host media using quantization index modulation(QIM).A novel watermarking technique in which coefficients in the doublelayered transform domain were modified using an HVSbased quantization scheme.The doublelayered transform coefficients were generated by discretecosine transforming(DCT) the weighted and pseudorandomly permuted wavelet components.The weights were obtained according to the human visual system so that the watermark energy is properly distributed in different frequency bands leading to a lower visual distortion.This technique can provide a good robustness and high capacity of embedded mark without any visual distortion.Relations between embedding capacity,impercepticbility and robustness were analyzed and verified with simulation results.更多还原