有效的调色板图像水印算法  

Valid Digital Watermarking of Palette-based Image

作　　者：杨成[1] 杨义先[1] 蔡满春[1] 

机构地区：[1]北京邮电大学信息安全中心,北京100876

出　　处：《中山大学学报（自然科学版）》2004年第A02期128-131,共4页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：国家973基础研究资助项目(TG1999035804);国家自然科学基金资助项目(4042022);教育部优秀青年教师资助项目

摘　　要：调色板图像与真彩图像相比具有色彩量化、独立调色板等特点。调色板图像作为被广泛使用的媒体类型,直接针对它的数字水印研究却非常少。通过分析目前调色板图像水印的主要方法,指出存在有效性低、失真严重、不能抵抗调色板分析攻击等缺点。针对以上问题,提出了一种有效的调色板图像水印算法。算法通过聚类分析来减少失真,使用梯度调整策略来增加嵌入容量,并采用频率对比方式完成对水印的嵌入和提取。在保证高的保真度前提下,算法有效性达到100%,并能抵抗调色板分析攻击、格式转换攻击和全选拷贝攻击等。The palette_based image is widely used in practical, such as in internet and in mobile network. But there is little research on the palette_based image in digital watermark field, since in contrast with the true color image, the palette-based image has quantized color cube and independent color table. By analyzing the present digital watermark methods of palette_based image, disadvantages of them are pointed out in this paper. They are low validity, severe visual distortion and resistlessness to the palette analysis. A valid digital watermark method of palette_based image is proposed. The cluster analysis is used to reduce the visual distortion, and the embedding capacity is increased by using the grads modulation scheme which is presented. Then the raw message is embedded into or extracted from the palette_based image by adjusting the color frequencies of nearest pixels in image. On the premise of guaranteeing the image fidelity, the proposed method is perfect valid which means the bit error rate is almost zero. Furthermore, the method can resists attacks of the palette analysis, the format transformation and the copy_paste operation.

关 键 词：调色板图像 数字水印 量化 有效性 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]