【摘要】 在传统的基于分形图象编码的数字水印技术的基础上提出了两种改进方案 ,并对 3种方案在加密图象的质量和鲁棒性两个方面进行了研究与探讨。由于这种数字水印技术是通过改变给定值域子块寻找最佳定义域子块的寻找区域来嵌入或读取水印的 ,所以改变寻找区域的划分方法可以有效的提高图象质量和数字水印的鲁棒性。实验结果表明 ,本文提出的方法可以获得较好的图象质量和较高的鲁棒性更多还原

【Abstract】 Two new digital watermarking techniques based on fractal image coding are proposed on the basis of the traditional one, and we research the three ways on the quality of images embedded with a digital watermark and robustness of watermark. The ways use the relationship of different parts of the original image as a means of embedding and retrieving a watermark, so we can change the search regions of a domain block given to improve the quality images and robustness. Experimental results show that the proposed ways can improve the quality of images signed and the robustness of digital watermark.更多还原