摘要：

为避免人眼评价不可见水印透明性时受疲劳、环境等因素的影响，提出一种与人类视觉感知一致的透明性评价方法。对原始图像和各含水印图像进行小波变换，按照人眼感知的敏感性对所得子图进行分类，形成相应的参考序列和比较序列，利用灰色关联分析理论计算原始图像与含水印图像对应各类序列之间的关联度，并根据水印嵌入面积比例和嵌入强度进行调整，将各类子图关联度加权，得到原始图像与各含水印图像的整体关联度，给出水印透明性的客观评价。实验结果表明，与PSNR等现有评价方法相比，该方法不仅正确有效、通用性好，而且细节区分能力强。

关键词: 数字水印, 透明性, 灰色关联分析, 人类视觉系统, 小波变换, 性能评价

Abstract:

In order to avoid the influence of some factors like tiredness or environment in the invisible watermarking evaluation via Human Visual System(HVS), this paper presents an efficient performance evaluation method on the imperceptibility, which is always consistant with human visual perception. In this method, after the original image and corresponding watermark-embedded images are decomposed by multilevel wavelet transform, their wavelet coefficients are divided into 4 categories in terms of the sensibility of HVS, and each of them is used to construct a reference sequence and some comparative sequences. The similarities of the two kinds of sequences are calculated by grey relational analysis, which is further adjusted with the consideration of the watermark-embedded-area ratio and the watermark-embedded coefficients. A global performance of imperceptibility of watermark-embedded images is obtained after the 4 grey relational degrees are combined with different weights. Experimental results show that compared to Peak Signal to Noise Ratio and some existing methods, the proposed method not only is efficient and universal, but also has a better ability to distinguish tiny details.

Key words: digital watermarking, imperceptibility, grey relational analysis, Human Visual System(HVS), wavelet transform, performance evaluation

中图分类号: 

• TP391.41