Simulation results show that the methods we presented have better performance . 2 . data hiding in the digital image combined with hvs ( human visual system ) , we can put secret message in the image without degrading the quality for its redundancy and to secure the information 2数字图象中的信息隐藏由于数字图象中包含了大量的冗余信息，结合人的视觉特性，我们可以把一些重要的秘密信息隐藏于图象中，而不会引起图象的失真，达到了对信息进行秘密传输的目的，在很大程度上保护了秘密传输的消息。
In dct - based system , select mid - frequency as the watermark carrier for the consideration of the tradeoff between the imperceptibility and robustness requirements . in dwt - base system , a couple of significant wavelet coefficients in detailed subbands are selected to embed watermarks by first level decomposing . a better image quality ( imperceptibility ) can be gained by exploiting human visual system 在dct水印系统中，选择dct系数的中频系数作为嵌入的载体(出于不可觉察性和健壮性的考虑) ；在dwt水印系统中，利用小波变换的多分辨率特性提取影响图像纹理的参数作为水印的载体，利用纹理的隐蔽特性，使得系统在保证健壮性的同时获得很好的不可觉察性。
A fingerprint image watermarking algorithm based on dwt - dft is studied : in consideration of the profile of image is embodied in low frequency part and the minutiae is in high frequency part . in this algorithm , the dwt coefficients of the watermark are embedded in the subband of low frequency of the image . with the features of human visual system ( hvs ) taken into account during embedding to make the algorithm adaptive 研究了一种将指纹灰度图像作为水印信息的dwt - dft ( discretewavelettransform - discretefouriertransform )变换域水印算法:数字图像的轮廓体现在低频部分,而细节体现在高频部分,本文将经过小波变换的指纹信息嵌入到图像的低频子带中,嵌入过程结合人眼视觉特性,实现了水印的自适应嵌入。
Most of these standards are based on the method of inter - frame motion compensation and two - dimensional discrete cosine transform ( 2d - dct ) and encode and describe the color video in ycbcr 4 : 2 : 0 format , which want to take advantage of human visual system ( hvs ) to save bit expense by decreasing the resolution of two color difference components 当前国际上的压缩标准普遍采用帧间运动补偿加帧内二维离散余弦变换的编码方法,并且将彩色视频序列表示为ycbcr格式,试图利用人眼的视觉特性降低对色差信号的分辨率来节省比特开销。
Then , both the k - sampling theory and the hvs ( human visual system ) theory are applied to digital watermarking embedment , resulting in two new strategies and the relevant algorithms as well as their implementations . the experimental results demonstrate that the present algorithms are of robustness and good imperceptibility 在此基础上将k采样理论和hvs （人类视觉系统）应用于数字水印处理，提出了两种数字图像水印处理的新策略，并实现了基于上述策略的数字水印算法，实例分析结果表明具有较好的鲁棒性和隐蔽性。
The early methods analyze the texture at a single scale . however , large numbers of psychophysical experiments and recent results suggest that the multi - channel analysis of the texture not only accord with the manner in which the image is analyzed by human visual system , but also bring better performance 早期的纹理分析方法都建立在单一尺度上,而大量的生物试验以及近期的研究结果都表明,对纹理的多通道分析不但符合人眼分析图像的方式,而且表现出良好的性能。
A digital watermark is an invisible mark embedded in digital images , video or audio documents , which can be used for a number of different purposes including copyright protection , authentication and captioning . according to the human visual system ( hvs ) , two watermark embedding algorithm is proposed employing the characteristics of multi - resolution analysis of the two - dimension discrete wavelet transform ( dwt ) 随着计算机和网络技术的飞速发展，数字图像、音频和视频产品越来越需要一种有效的版权保护方法，所谓数字水印就是一种嵌入到图像、视频或音频数据中的不可见标志，可以用于多媒体数据的版权保护、认证和标注等。
Fractal image compression coding ( ficc ) is a new image coding method developed in recent years and has been studied extensively . based on the analyze of conventional fractal coding and decoding , a fractal image coding algorithm based on changeable threshold and creative function is proposed in this paper . new algorithm is to be in accordance with the feature of human visual system 本文通过对传统分形图像压缩编解码的分析，提出了门限变化和生成函数改进的编码算法，此算法在一定程度上与人类视觉系统特性相符，我们在理论上证明了在相同的条件下，用改进的生成函数恢复的图像在质量方面比传统的生成函数要好，恢复图像的信噪比有所提高。
