摘要
水印的视觉不可感知性反映了水印化图像的保真程度。分析了人类视觉对频率、亮度、纹理以及色彩的掩蔽,以Watson的灰度图像DCT域JND(just noticeable differences)值计算模型为基础,再结合色彩对视觉的掩蔽,给出彩色图像JNCD(just noticeable color differences)值计算方法,计算出图像中不同成份的视觉掩蔽权值,给出一个基于这些权值的彩色图像水印不可感知性评价模型,即CPSNR(color image peak signal to noise ratio)。实验证明,CPSNR的判定结果与人眼的视觉感知结果一致,可用于对水印算法进行不可感知性性能评价。
Imperceptibility of embedded digital watermark reflects the fidelity of watermarked image. The masking of frequency, luminance, texture and color on human vision were analyzed. Based on the color masking and Watson＇s JND（just noticeable differences） model, a calculation method of JNCD（just noticeable color differences） for color image was proposed. Then the masking weight for each element of color image was calculated using the JNCD. A new imperceptibility measure of watermark in watermarked color image was proposed based on these masking weights, i.e. CPSNR （color image peak signal to noise ratio）. Experimental results show that the quality of watermarked color image calculated by CPSNR is the same as the result judged by human vision, and CPSNR can be used to evaluate the imperceptibility of watermarking methods.
出处
《通信学报》
EI
CSCD
北大核心
2008年第2期95-100,共6页
Journal on Communications
基金
国家自然科学基金资助项目(70371052)~~
关键词
数字水印
彩色图像
不可感知性评价
峰值信噪比
digital watermarking
color image
evaluation of imperceptibility
peak signal to noise ratio
