A novel Iossless data hiding scheme based on a combination of prediction and the prediction-error adjustment （PEA） is presented in this paper. For one pixel, its four surrounding neighboring pixels are used to predict it and 1-bit watermark information is embedded into the prediction-error. In traditional approaches, for the purpose of controlling embedding distortion, only pixels with small predictionerrors are used for embedding. However, when the threshold is small, it is difficult to efficiently compress the location map which is used to identify embedding locations. Thus, PEA is introduced to make large prediction-error available for embedding while causing low embedding distortions, and accordingly, the location map can be compressed well. As a result, the hiding capacity is largely increased. A series of experiments are conducted to verify the effectiveness and advantages of the proposed approach.
几何攻击会给数字水印带来同步误差和插值误差,现有的多数抗几何攻击的鲁棒水印方法都把焦点集中在同步误差上,对插值误差的研究甚少。介绍了常见的插值算法并指明了插值误差产生的原因,能够实现最佳的嵌入率、嵌入失真以及鲁棒性之间平衡的QIM(quantization index modulation)水印算法,进而分析了插值误差对QIM算法的影响,在此基础上提出了针对插值误差的逐像素点选择QIM水印算法。实验在纹理程度不同的10幅图像上进行。实验证明,提出的水印算法对插值误差的鲁棒性优于原始的QIM水印算法。
