用子波变换模拟视觉信息提取过程

利用逆变换研究了ＤＯＧ子波变换在提取输入信号时的特性，指出了尺度逐次变化的子波变换表现出的由粗到精的信息提取性质和局域特性与人类视觉系统对光学图像信息的提取过程的某些方面有相似性．本文认为ＤＯＧ于波变换将是研究人类视觉系统信息处理机制的重要工具．     

一种基于图象融合的数字水印方法

提出了一种基于多分辨率图象融合的数字水印算法.该算法基本思想源自公开钥加密系统与Torus自同构映射置乱的概念,并根据视觉系统HVS的照度掩蔽特性及组合规则,以原始图象的子波分解级数为依据,对原始图象及水印的子波变换系数进行融合,以实现水印在原始图象空间位置和频率方向上的嵌入.实验结果表明,该算法具有良好的鲁棒性和可行性.     

子波变换提取图像的边缘及角点信息

本文详细介绍Ｍｅｘｉｃａｎ－ｈａｔ子波变换的定义和基本特性，通过选取不同的子波函数，提取图像的边缘与角点信息。     

基于感兴趣区域的幅型比变换新方法

基于人类视觉系统对运动目标比较敏感的特性,提出了一种新的幅型比变换方法.综合时空信息提取视频序列中的运动目标,利用图像修复技术对被提取运动目标后的视频图像进行背景修补.采用插值算法以不同的方式分别缩放运动目标和修复后的背景,并将变换后的运动目标与背景相叠加合成相应幅型比的视频图像.实验结果表明:此方法避免了已有幅型比变换方法的缺陷,保证了变换后运动目标的无失真性,与人类的视觉感知有较好的一致性.     

基于感兴趣区域的幅型比变换新方法

基于人类视觉系统对运动目标比较敏感的特性,提出了一种新的幅型比变换方法.综合时空信息提取视频序列中的运动目标,利用图像修复技术对被提取运动目标后的视频图像进行背景修补.采用插值算法以不同的方式分别缩放运动目标和修复后的背景,并将变换后的运动目标与背景相叠加合成相应幅型比的视频图像.实验结果表明：此方法避免了已有幅型比变换方法的缺陷,保证了变换后运动目标的无失真性,与人类的视觉感知有较好的一致性.     

应用计算全息制作的子波匹配滤波器实现光学子波变换的研究

介绍了一种应用计算全息制作的子波匹配滤波器实现光学子波变换的新方法，应用计算全息制作Ｈａａｒ子波函数的匹配滤波器和光学Ｖａｎｄｅｒ Ｌｕｇｔ相关器实现了二维子波变换，给出了实验结果。这种方法可实现任意子波函数的光学子波变换，且简单易行。     

子波变换及其在污染云团红外光谱监测与识别中的应用

反应离散子波变换进行污染云团红外光谱信号分析及特征提取，离散子波变换具有时－频分析特性，能将信号的细微变化反映出来，对实时遥感获取的目标云团作离散子波变换分析的结果表明：离散子波变换可明显提高目标云团的特性，十分有利于光谱的识别。     

临界频带子波变换用于混叠语音分离的研究

以反映听觉特性的临界频带子波变换为工具,对混叠语音进行了分析,提出了一种基于临界频带子波变换的混叠语音源信号基音分离和检测方法,在此基础上利用数字多谐振荡器的选频特性,有效地获取构成混叠语音的每个语音信号的各谐波分量,以此实现从混叠语音中分离出各源信号。实验结果表明混叠语音分离方法是可行有效的。     

基于联合子波变换的目标轮廓抽取技术

子波变换是目标特征抽取的有效方法。本文把联合变换相关技术与子波变换结合起来，建立了一套新的子波变换光学实验系统。推导了联合子波变换的基本理论，并给出了联合子波换相关器在目标特征抽取应用中的实验结果。     

一维投影α模型的子波关联

对二维相空间的两种典型的自仿射分形作了一维投影,对所得到的一维投影a模型,从特征函数着手,研究了模型的关联密度和子波关联矩,找出了分割数Λ=2,3,4的子波基函数和关联矩,得到了二阶子波关联矩解除子波幅之间的关联耦合的结论,并对这一结论给出了模型无关的普遍证明.     

Symplectic wavelet transformation

Usually a wavelet transform is based on dilated-translated wavelets. We propose a symplectic-transformed-translated wavelet family psi(*)(r,s)(z-kappa) (r,s are the symplectic transform parameters, |s|(2)-|r|(2)=1, kappa is a translation parameter) generated from the mother wavelet psi and the corresponding wavelet transformation W(psi)f(r,s;kappa)=integral(infinity)(-infinity)(d(2)z/pi)f(z)psi(*)(r,s)(z-kappa). This new transform possesses well-behaved properties and is related to the optical Fresnel transform in quantum mechanical version.     

The wavelet response as a multiscale NDT method

We analyze interfaces by using reflected waves in the framework of the wavelet transform. First, we introduce the wavelet transform as an efficient method to detect and characterize a discontinuity in the acoustical impedance profile of a material. Synthetic examples are shown for both an isolated reflector and multiscale clusters of nearby defects. In the second part of the paper we present the wavelet response method as a natural extension of the wavelet transform when the velocity profile to be analyzed can only be remotely probed by propagating wavelets through the medium (instead of being directly convolved as in the wavelet transform). The wavelet response is constituted by the reflections of the incident wavelets on the discontinuities and we show that both transforms are equivalent when multiple scattering is neglected. We end this paper by experimentally applying the wavelet response in an acoustic tank to characterize planar reflectors with finite thicknesses.     

相干态的小波变换

根据小波变换的量子力学机理, 通过选取不同的系数, 构造出两组新的母小波函数. 在此基础上, 利用正规乘积内积分技术, 推导出相干态和粒子数态的小波变换, 并数值模拟出它们的小波变换图谱.     

二维小波变换及在青藏高原地形重构中的应用

计算和检验了4种不同小波基底和不同阶小波基底对单脉冲和尖峰两个信号的分解及重构的性质,结果表明双正交小波的精度最高,Coifman小波的精度最低.通过设阈值对小波和快速Fourier变换进行截断后再重构,说明小波具有重构精度高、所用非零系数少以及误差被局域化等优点,这就削弱了"Gibbs现象",限制了它的影响范围.在此基础上,用二维快速Fourier和二维离散小波变换对实际青藏高原及其附近地形做了分解、重构及截断后重构等,说明二维小波变换能以较之FFT更少的非零系数和误差局域化等重构大地形,表明了二维小波变换在未来大气环流数值模式中的应用潜力.     

Acquisition time reduction in magnetic resonance spectroscopic imaging using discrete wavelet encoding

This paper describes a new magnetic resonance spectroscopic imaging (MRSI) technique based upon the discrete wavelet transform to reduce acquisition time and cross voxel contamination. Prototype functions called wavelets are used in wavelet encoding to localize defined regions in localized space by dilations and translations. Wavelet encoding in MRSI is achieved by matching the slice selective RF pulse profiles to a set of dilated and translated wavelets. Single and dual band slice selective excitation and refocusing pulses, with profiles resembling Haar wavelets, are used in a spin-echo sequence to acquire 2D-MRSI wavelet encoding data. The 2D space region is spanned up to the desired resolution by a proportional number of dilations (increases in the localization gradients) and translations (frequency shift) of the Haar wavelets (RF pulses). Acquisition time is reduced by acquiring successive MR signals from regions of space with variable size and different locations with no requirement for a TR waiting time between acquisitions. An inverse wavelet transform is performed on the data to produce the correct spatial MR signal distribution.     

光学小波匹配滤波器与图形识别

小波变换弥补了傅里叶变换的不足，在信号及图像处理方面具有广阔的应用前景。文章深入讨论了小波变换匹配滤波器的理论基础及光学实现方法，并将其用于图形识别，给出了计算机模拟结果，与传统的匹配滤波器进行了比较，证实了小波变换在光学信息处理中的优越性。     

基于小波阈值滤波的激光陀螺消噪方法

利用小波多分辨率分析的特点和分形噪声在小波变换域的特性,采用小波变换域参数估计方法获得噪声参数,然后采用小波阈值滤波方法去除噪声,并比较了三种小波基不同的滤波效果.通过仿真试验,陀螺的零漂值从0.3755°/h减小到了0.1026°/h.     

Phase recovery from fringe patterns using the continuous wavelet transform

Interferometry is well established as an optical technique in which a measurand is encoded as the phase of a periodically varying intensity pattern. In view of the inherent accuracy of interferometry, many methods have been developed to retrieve the phase from images of the fringe pattern. Our focus in this paper is one such technique—the continuous wavelet transform (CWT). We begin by reviewing the CWT and the space–spatial–frequency localisation properties of wavelets. We show that a path which follows the maximum modulus of the CWT (the wavelet ridge) gives the instantaneous fringe frequency as a function of spatial displacement. The phase is automatically and trivially obtained, without discontinuities, by integration. Examples of practical wavelets are given and algorithms to isolate the wavelet ridge reviewed.     

General formula for finding mother wavelets by virtue of Dirac's representation theory and the coherent state

The admissibility condition of a mother wavelet is explored in the context of quantum optics theory. By virtue of Dirac's representation theory and the coherent state property we derive a general formula for finding qualified mother wavelets. A comparison between a wavelet transform computed with the newly found mother wavelet and one computed with a Mexican hat wavelet is presented.