基于HVS和DWT的双彩色数字图像水印技术

根据HVS系统,人眼对于红、绿、蓝三色的敏感程度是不同的。人眼对于蓝色分量最不敏感,故嵌入水印有良好的透明性,但同时在红色分量中嵌入水印具有良好的鲁棒性。为解决水印嵌入的视觉失真问题,采用了不同基色对应不同的加权系数的水印嵌入方案。同时,将彩色水印图像嵌入彩色宿主图像的中频段以及多次嵌入低频段来增加算法的鲁棒性。仿真结果表明,该算法具有较好的透明性,且提取水印效果较好。     

一种基于HVS和DC分量的DCT域数字水印算法

为增强数字水印的透明性和鲁棒性,提出了一种基于人类视觉系统和直流分量的DCT变换域数字水印算法。算法依据原始图像的纹理掩蔽特性确定水印信息的嵌入位置,依据照度掩蔽特性确定水印信息的嵌入强度,将二值水印图像嵌入到原始图像在DCT域的直流分量中。在仿真实验中与同等条件下的中频嵌入做比较,实验结果表明,该算法提取的水印具有良好的透明性和鲁棒性。     

基于时域同步及分块嵌入的音频水印算法

提出一种基于时域同步的音频水印算法,在音频信号的时间域上检索满足一定信号强度的区域作为同步区域,把水印图像分块,每个水印分块及其编号嵌入到一个同步区域,水印按照分块顺序循环嵌入到检索到的同步区域;水印比特嵌入在同步区域的小波变换域上,通过拼凑法修改低频系数的幅度值实现水印比特的嵌入。水印检测不需要原始音频信号,是一种盲检测水印算法。仿真实验证明了算法对一般的音频信号处理具有较好的鲁棒性和透明性,对同步攻击、抖动攻击具有较好的鲁棒性。     

基于DWT-SVD的彩色图像水印算法

本文根据奇异值分解理论把灰度水印嵌入到彩色图像的DWT分量中。为了既能保证算法的鲁棒性,又能够尽可能地提高不可见性,先将原图像分为RGB三个分量,将水印的信息添加到了RGB空间的B分量上,实验证明水印嵌入到蓝色分量比嵌入到其他颜色分量中可以更好地保持原始图像的感知质量。本文在提取水印时设定了阈值,如果奇异值分解对角线上的值低于这个阈值,就会用上面一行的值代替对角线上的值。实验证明,该方案对JPEG压缩和中值滤波等处理具有较好的鲁棒性。     

基于三维离散余弦变换的鲁棒彩色图像水印算法

针对常见的彩色图像水印算法仅在亮度分量或在每一分量嵌入水印,致透明性和鲁棒性不能达到权衡的问题,提出了一种新颖的基于三维离散余弦变换的RGB彩色图像水印算法。为增强水印的安全性,先对水印图像进行异或加密和Arnold置乱处理;其次对彩色图像进行互不重叠的分块处理,并对每一分块进行三维离散余弦变换;最后对每一分块三维离散余弦变换后的第一个系数采用量化的嵌入方法嵌入水印信号。实验表明,提出的算法具有较好的透明性和鲁棒性,对彩色图像的版权保护应用具有一定的应用价值。     

兼具版权保护和内容认证彩色图像双水印算法

提出了一种新的多功能彩色数字图像双水印算法。提取原始彩色图像的R、G、B3个色彩通道,在蓝色分量B的中频系数上嵌入扩频后的版权水印。再根据绿色分量G生成认证水印,嵌入在量化后的提升小波系数上,不需要考虑两种水印的嵌入顺序。实验表明。版权水印具有很好的抗剪切性,鲁棒性较强、透明性较好;认证水印可精确进行图像篡改检测和定位。     

基于Mean Shift和L*u*v*彩色空间改进的FH图像分割方法

针对FH算法(Felzenszwalb和Huttenloch提出的图像分割算法)中存在的欠合并现象,在L*u*v*彩色空间,结合Mean Shift算法,提出了一种改进FH图像分割方法,即IFH(Improved FH)。该方法首先采用Mean Shift算法获得均值漂移图像,再将图像由RGB空间转换到L*u*v*颜色空间;然后,结合L*u*v*彩色空间,采用FH算法构造带权无向图,基于图像的颜色特征进行分割。实验证明,与原算法相比,该方法在分割精度与分割质量上有了很大程度的提高。     

Contourlet-SVD域的YIQ彩色图像全息水印算法

选取YIQ域的颜色空间将共轭对称扩展傅立叶数 字全息技术与Contourlet-SVD域 进行结合,提出一种基于YIQ和Contourlet-SVD域的彩色图像全息水印算法。由于在RGB 图像的任一分量嵌入水印对视觉影响较大,所以选择将RGB图像转换成YIQ域的颜色空间, 选取亮度分量Y进行2层Contourlet变换,在得到的细节子带中选取低频系数进行SVD奇 异值分解,将对水印图像进行共轭对称扩展傅立叶数字全息方法所生成得水印信息隐藏。 最后的实验结果表明,该算法可以保证水印嵌入足量的基础上,确保了水印信息的较强抵 抗能力。该算法对高斯噪声、JPEG压缩攻击的鲁棒性较强,NC值均达到0. 91     

基于ICA小波的数字水印方案

基于独立分量分析(ICA)和小波变换理论,提出一种新的图像数字水印方案.该方案在小波域利用ICA的方法完成水印嵌入和检测.计算机仿真结果表明该方案具有较好的透明性和鲁棒性.     

一种基于快速独立分量分析的图像水印算法

本文提出了一种基于快速独立分量分析的图像水印算法。该方法是把一幅二值水印图像嵌入到原图像的小波逼近子图中,检测时利用一种FICA(快速独立分量分析)方法来提取水印。实验证明,该水印具有较好的透明性和较好的鲁棒性。     

Selective color transferring via ellipsoid color mixture map

Color transfer among images is a natural phenomenon and important research topic in interactive graphics and augmented environments. Most of the conventional methods need complex user interactions and difficult image segmentation. Motivated for the intuitive use of color editing tools, this paper presents a simple but effective ellipsoid color mixture map to realize selective color transfers. Our approach proposes ellipsoid hulls to represent color statistics of the images. Based on the window-click input, the system computes the ellipsoid hulls of the source and target images respectively. The color mixture map is generated to determine the blending weight of pixels in the output image, according to the color and distance information instead of using image segmentation. By mixing the images using the color mixture map, the final results we produce have the source color selected realistically spreading on the structures related to the target window. Our selective color transferring approach is efficient and simple to use, and widely applicable for images and also video sequences without the need of addition interaction. Our experimental results have showed the high-quality visual effects and efficiency of image/video color transfers.     

Novel color demosaicking for noisy color filter array data

Single sensor digital color still/video cameras use color demosaicking to reproduce full color images from color filter array (CFA) data. The quality of interpolated image will be degraded due to the sensor noise introduced during the image capture process. Many conventional demosaicking-denoising solutions adopt the channel-dependent noise model, which may fit the CMOS/CCD image sensor less than signal-dependent noise model. In this paper, the wavelet sub-band decomposition and synthesis are applied to interpolate the CFA data with signal-dependent noise model. The major contributions of this work include: (1) The combination of LMMSE and statistical calculation in wavelet domain are utilized to suppress the signal-dependent noise, which is separated into additive noise and multiplicative noise. (2) In CFA data, it has been verified that the quantitative relationship between the current pixel and the adjacent pixel, which locate in the same edge. Both simulated and real CFA images are employed to compare the proposed algorithm with the state-of-the-art techniques reported in the literature. The experimental results confirm that our method outperforms them both on demosaicking performance and on computational cost, when they process the noisy color filter array data.     

基于颜色梯度特性的彩色图像隐写分析

基于彩色图像任意2个颜色通道间梯度方向随机序列及颜色梯度和随机序列的振荡特性在隐写前后均有明显变化的特征,提出了一种基于颜色梯度特性的彩色图像盲隐写分析算法。算法应用HHT(Hilbert-Huang transform)提取4个序列在隐写前后的内在振荡特征差异,构建基于Hilbert谱的特征向量,采用SVM分类器进行分类判别。实验表明,该算法误检率低,检测性能优于现有彩色图像隐写分析算法,可以实现彩色图像隐写的可靠检测。     

一种色彩改进型Retinex彩色图像增强方法

提出了一种色彩改进型Retinex彩色图像增强方法.对于曝光量不足的彩色图像,采用多尺度Retinex算法增强后,在亮度平均值附近以1倍标准差进行截取,拉伸后的图像亮度与对比度的乘积较大,再采用Brovey彩色变换方法,以原图像各像素中红绿蓝所占的成份比例进行运算.由色彩改进型Retinex彩色图像增强方法增强后得到的图像信息熵是直接使用Retinex算法的1.019±0.002倍.     

An effective color scale for simultaneous color and gray-scale publications

Pseudocolored images are used in many signal processing applications to represent signal properties as a function of two independent variables, such as time and frequency. This paper describes a color scale that can be used to unambiguously represent these images in printed gray-scale publications as well as full color electronic publications. The image resolution when viewed in color is enhanced in this article. This color scale also allows for correct interpretation by people with common types of color blindness, which accounts for approximately 10% of the male population and 1% of the female population. While it may be possible to obtain a better resolution with a color scale that is designed for a particular image on hand, the proposed color scale works well in many applications where the user does not have the time or resources to tailor the color scale to a specific image. The proposed color scale is also easy to implement and has an intuitive interpretation in that it cycles through a sequence of hues that roughly resembles the familiar rainbow.     

A CCD color signal separation IC for single-chip color imagers

A CCD color signal separation IC for solid-state imagers with color filter arrays is described. The device simplifies peripheral circuitry and enhances picture qualities such as resolution, color fidelity, and stability for single-chip color imaging systems, by incorporating CCD delay lines, sample-and-hold circuits, and dual clamp circuit. Also described is a new geometry color filter array which is required by the separation IC. Color image corresponding to horizontal resolution of 340 TV lines with no erroneous color has been obtained from the device when used with a 580 × 475 element CCD imager.     

Fuzzy color histogram and its use in color image retrieval

A conventional color histogram (CCH) considers neither the color similarity across different bins nor the color dissimilarity in the same bin. Therefore, it is sensitive to noisy interference such as illumination changes and quantization errors. Furthermore, CCHs large dimension or histogram bins requires large computation on histogram comparison. To address these concerns, this paper presents a new color histogram representation, called fuzzy color histogram (FCH), by considering the color similarity of each pixel's color associated to all the histogram bins through fuzzy-set membership function. A novel and fast approach for computing the membership values based on fuzzy c-means algorithm is introduced. The proposed FCH is further exploited in the application of image indexing and retrieval. Experimental results clearly show that FCH yields better retrieval results than CCH. Such computing methodology is fairly desirable for image retrieval over large image databases.     

Digital color halftoning

Digital color halftoning is the process of transforming continuous-tone color images into images with a limited number of colors. The importance of this process arises from the fact that many color imaging systems use output devices such as color printers and low-bit depth displays that are bilevel or multilevel with a few levels. The goal is to create the perception of a continuous-tone color image using the limited spatiochromatic discrimination capability of the human visual system. In decreasing order of how locally algorithms transform a given image into a halftone and, therefore, in increasing order of computational complexity and halftone quality, monochrome digital halftoning algorithms can be placed in one of three categories: 1) point processes (screening or dithering), 2) neighborhood algorithms (error diffusion), and 3) iterative methods. All three of these algorithm classes can be generalized to digital color halftoning with some modifications. For an in-depth discussion of monochrome halftoning algorithms, the reader is directed to the July 2003 issue of IEEE Signal Processing Magazine. In the remainder of this article, we only address those aspects of halftoning that specifically have to do with color. For a good overview of digital color halftoning, the reader is directed to Haines et al. (2003). In addition, Agar et al. (2003) contains a more in-depth treatment of some of the material found in this work.     

A CCD color signal separation IC for single-chip color imagers

A CCD color signal separation IC for solid-state imagers with color filter arrays is described. The device simplifies peripheral circuitry and enhances picture qualities such as resolution, color fidelity, and stability for single-chip color imaging systems by incorporating CCD delay lines, sample-and-hold circuits, and dual clamp circuit. Also described is a color filter array utilizing Bayer geometry, which is used in the separation IC. Color images corresponding to a horizontal resolution of 340 TV lines with no erroneous color have been obtained from the device when used with a 580/spl times/475 element CCD imager.     

色彩传感器的选择-三种成本-效益型方案各有千秋

用于色彩感测的元件一贯被认为是造价昂贵的,而且还需要精密的支持电路,从而使其应用领域主要局限于专用仪表.但是,具有更高集成度的新型色彩传感器技术已经面市,这为实现成本-效益性更好的解决方案奠定了基础.