一种新的图像水印方案

目标区域是图像中视觉上最重要的部分。针对现有的水印算法很少考虑图像中确定的目标区域这一问题，提出了一种基于目标区域的水印方案(WIOR)。方案首先利用小波变换分析图像的目标特征，并依据图像的小波高频系数特征对其进行聚类，获得水印的嵌入域，在此嵌入域中，选择小波系数并对其进行量化调制来嵌入二值扩谱水印；同时，通过只在图像的局部区域内嵌入较少的水印信息来改善水印的隐蔽性。实验结果表明，该方案对于一类具有突出目标特征的图像具有较好的效果。嵌入的水印主要优势在于真正把水印嵌入图像的视觉重要部分，从而能有效地抵御剪切攻击，而且可以实现盲检测。     

基于小波包分析及支持向量机的超音速目标识别方法研究

提出了基于小波包分析及支持向量机的超音速目标识别方法 .通过 5 .5 6mm ,7.6 2mm和 12 .7mm三种枪弹试验获取信号 ,用小波包分解激波信号 ,统计每个频带的能量特征 ,用支持向量机方法训练测试样本 ,获得了很好的分类效果 .仿真结果表明基于超音速飞行体产生的激波信号来识别目标是可行的 .     

半参数回归模型中小波估计的随机加权逼近速度

把小波光滑方法和随机加权方法结合在一起，获得了半参数回归模型中参数分量的小波估计的随机加权逼近速度为σ(n^-1/2)。因此，从大样本意义上说，小波光滑方法和随机加权方法对半参数回归模型是可用的。     

ROI-based Watermarking Scheme for JPEG 2000

A new region of interest (ROI)-based watermarking method for JPEG 2000 is presented. The watermark is embedded into the host image based on the characteristics of the ROI to protect rights to the images. This scheme integrates the watermarking process with JPEG 2000 compression procedures. Experimental results have demonstrated that the proposed watermark technique successfully survives JPEG 2000 compression, progressive transmission, and principal attacks.     

Singularity spectrum of fractal signals from wavelet analysis: Exact results

The multifractal formalism for singular measures is revisited using the wavelet transform. For Bernoulli invariant measures of some expanding Markov maps, the generalized fractal dimensions are proved to be transition points for the scaling exponents of some partition functions defined from the wavelet transform modulus maxima. The generalization of this formalism to fractal signals is established for the class of distribution functions of these singular invariant measures. It is demonstrated that the Hausdorff dimensionD(h) of the set of singularities of Hölder exponenth can be directly determined from the wavelet transform modulus maxima. The singularity spectrum so obtained is shown to be not disturbed by the presence, in the signal, of a superimposed polynomial behavior of ordern, provided one uses an analyzing wavelet that possesses at leastN>n vanishing moments. However, it is shown that aC behavior generally induces a phase transition in theD(h) singularity spectrum that somewhat masks the weakest singularities. This phase transition actually depends on the numberN of vanishing moments of the analyzing wavelet; its observation is emphasized as a reliable experimental test for the existence of nonsingular behavior in the considered signal. These theoretical results are illustrated with numerical examples. They are likely to be valid for a large class of fractal functions as suggested by recent applications to fractional Brownian motions and turbulent velocity signals.     

Application of Discrete Wavelet Transform in the Analysis of Nonlinear Chemical System

Oscillations of species concentration are phenomena accompanying several types of electrochemical and purely chemical processes. Importance of analyzing of such processes results from both scientific and practical reasons. In the paper the authors deal with investigation of time dependent spectra of various stages of Belousov-Zhabotinsky type chemical oscillations. As the analytical tool the discrete wavelet transform is proposed.     

基于小波变换的在役管线漏磁信号的去噪

采用漏磁法对在役管线进行无损检测时,所采集的信号中含有大量的噪声需要去除。文中介绍了小波变换的基本理论及检测信号和噪声信号在小波变换下的特性,说明了去除漏磁信号噪声的原理。在仿真试验中采用二阶双正交样条小波为小波函数,选用软硬阈值折中法和自适应阈值处理小波系数,结果表明将小波变换应用于在役管线漏磁检测中,能很好地去除噪声,提取出有用信号。     

基于模糊理论的空间屏蔽滤波信号去噪

基于模糊理论提出了一种空间屏蔽滤波信号去噪方法.对信号进行二进小波变换后,对信号进行空间屏蔽滤波,对于未通过滤波器的系数进行模糊阈值处理实现去噪.通过对含噪HeaviSine和Doppler信号的去噪仿真,表明,该方法对噪音具有良好的抑制作用,能较好地保持信号在间断点处的信息.与传统空间屏蔽滤波相比,该方法对不同种类的含噪信号均具有良好的去噪效果.     

基于小波能量距的雷达距离像特征提取

基于小波分析的方法,采用雷达目标一维距离像回波在不同频带的能量距特征,以此特征为基础,利用径向基概率神经网络对4类目标进行识别,并与传统的子带能量特征方法进行对比,仿真实验结果表明：对雷达目标距离像进行特征提取时,能量距特征更好地利用了小波分析的时频信息,所得特征向量类间类内距离比大于能量特征,目标的可分性更好,识别率得到了提高,因而能量距特征优于能量特征。