复杂轨迹合成孔径雷达后向投影算法图像流GPU成像

相对于基于傅里叶变换的频域成像算法,后向投影( BP)算法因采用时域逐点相干积累,更适合于复杂轨迹合成孔径雷达( SAR)高精度成像。但BP算法计算量巨大,限制了其应用于SAR大场景大数据量快速成像。图形处理器( GPU)具有强大浮点运算和并行处理能力,为大场景BP算法快速成像实现提供了途径。结合GPU并行处理,提出了一种基于图像流的复杂运动SAR大场景BP快速成像处理方法。该方法借助BP算法中图像像素点相互独立处理的特性,采用图像像素点并行及图像流程处理,设计了孔径与图像缓存调度方案,提高SAR大场景大数据BP算法成像效率。仿真和机载实测数据结果验证了方法的有效性,在有限GPU显存条件下实现了8192×8192大场景快速成像,并且成像加速比相对于传统CPU单线程处理可达300倍以上。     

基于独立分量分析的多分辨率遥感图像融合算法

研究了目前常用的遥感图像融合方法,提出了基于独立分量分析的多分辨率遥感图像融合方法,分析了用于独立分量分析的目标函数（如峭度、近似负熵和互信息）,给出了独立分量分析的优化快速算法,并详细描述了提取源信息独立分量的具体步骤。最后,将独立分量分析法应用于高分辨率光学图像和低分辨率光学图像的融合,与采用主分量分析法融合的图像相比,图像质量得到很大的提高。     

基于独立分量分析的高光谱图像目标检测算法

提出一种基于独立分量分析(ICA)的高光谱图像目标检测算法.首先利用无监督正交子空间投影进行端元提取,并将端元矢量构成矩阵作为快速定点独立分量分析的初始化混合矩阵,解决了独立分量在排序上的随机性;同时采用基于噪声调整的主分量分析(NAPCA)对原始图像数据降维,继而采用初始化后的快速独立分量分析从保留的主分量中依次提取出目标.利用AVIRIS高光谱数据进行实验研究,结果表明提出的算法能够有效地提取图像中的目标信息,其性能优于改进的CEM检测算法.     

基于激光成像及VR技术的多视点图像场景重构技术

为了提高多视点激光图像的场景重构能力,提出基于激光成像及VR技术的多视点图像场景重构技术。建立多视点激光场景图像虚拟现实三维重构模型,在大气散射环境下进行多视点激光场景图像的光强自适应融合,采用分块特征匹配技术进行多视点激光场景图像的信息增强处理,采用激光散射光晕点匹配方法进行多视点激光场景图像的细化滤波处理,采用激光散射光晕点特征检测方法进行图像特征提取,使用亮度分量进行多视点激光场景图像特征细节透射分析,对提取的多视点图像场景特征信息采用卷积神经网络学习方法进行多视点激光场景图像场景融合和特征重构,实现多视点激光场景图像虚拟现实三维重构。仿真结果表明,采用该方法进行多视点激光场景图像虚拟现实三维重构的精度较高,峰值信噪比较高,图像细节特征分辨力和准确性较好。     

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。     

改进型快速ICA算法与数学形态学结合的图像分割方法

介绍了一种改进型快速独立分量分析(FastICA)算法与形态学相结合的图像分割方法.该方法把图像的特征分量看作是边缘图像分量与其它背景图像分量的结合,把快速ICA对图像分量的提取,变为对边缘图像分量的提取,得到边缘图像的独立分量,再通过数学形态学的方法对边缘图像进行增强处理,从而实现图像的分割.实验结果表明:与传统的图像分割方法相比,该方法具有良好的图像分割性能,可以清楚地观察到图像轮廓,图像边缘的连通性较好且保留了原图像的很多细节,分割效果较好.     

基于线性和非线性算法的高效人脸识别系统

文中提出了一种基于外观的线性和非线性人脸识别方法,所用的线性算法有主成分分析(PCA)和线性判别分析(LDA)。两种非线性方法分别是核主成分分析(KPCA)及核费希尔分析(KFA),线性降维投影方法基于二阶相依性编码模式信息,非线性方法用于处理三个或更多像素之间的关系。首先通过Gabor对图片进行预处理,然后采用线性、非线性分析进行降维。通过马哈利诺比斯-余弦(Mahcos)度量用于定义两幅图像通过相应的降维技术后的相似性度量。实验表明,当与Gabor小波一同使用时,LDA和KFA的性能最高,分别为CMC和ROC结果的93.33%。通过对AT&T数据库400幅图像的综合分析,发现线性和非线性算法的性能受图像分类数目、图像预处理及识别测试集的人脸图像数目的影响。     

基于快速独立分量分析的红外运动小目标的检测

针对红外图像运动小目标的特点,将包含复杂背景和运动小目标的图像序列视作混合信号,目标可视作为其中一个独立分量,应用快速独立分量分析(FastICA)将此独立分量从混合信号中分离出来,以检测出运动小目标.试验结果表明,此分析方法简单,速度快,适应性较强.     

基于独立分量分析新算法的含噪图像盲分离

由于乘性噪声的存在,严重限制了标准ICA的使用。在分析独立分量分析的基本模型的基础上,讨论了有噪信号的独立分量分析(Noisy ICA)。提出一种新的基于四阶统计量的方法来消除乘性噪声,分离出独立的源信号。通过寻求噪声线性转换的统计结构,依据代价函数最小来获取解混阵B,从而分离出多维观测信号。最后把算法应用于含噪的混合图像,通过仿真显示算法很好的分离了源信号。     

无深度反转的集成成像一次拍摄方法

针对传统集成成像显示技术存在深度反转,需要进行二次成像的问题,提出一种无深度反转的集成成像一次拍摄方法。该方法采用离轴平行式集成成像拍摄结构对三维(3D)场景进行拍摄,通过设计合理的拍摄参数,重排图像元,生成无梯形畸变的图像阵列(EIA),直接用于集成成像显示,解决了传统集成成像的深度反转问题,避免了复杂且繁琐的图像校正和二次成像过程,可快速生成具有正确深度信息的EIA。该方法所获取的EIA在集成成像3D显示实验中重建的3D图像具有正确的深度和逼真清晰的立体显示效果,验证了本文方法的正确性。     

Linear spectral random mixture analysis for hyperspectral imagery

Independent component analysis (ICA) has shown success in blind source separation and channel equalization. Its applications to remotely sensed images have been investigated in recent years. Linear spectral mixture analysis (LSMA) has been widely used for subpixel detection and mixed pixel classification. It models an image pixel as a linear mixture of materials present in an image where the material abundance fractions are assumed to be unknown and nonrandom parameters. This paper considers an application of ICA to the LSMA, referred to as ICA-based linear spectral random mixture analysis (LSRMA), which describes an image pixel as a random source resulting from a random composition of multiple spectral signatures of distinct materials in the image. It differs from the LSMA in that the abundance fractions of the material spectral signatures in the LSRMA are now considered to be unknown but random independent signal sources. Two major advantages result from the LSRMA. First, it does not require prior knowledge of the materials to be used in the linear mixture model, as required for the LSMA. Second, and most importantly, the LSRMA models the abundance fraction of each material spectral signature as an independent random signal source so that the spectral variability of materials can be described by their corresponding abundance fractions and captured more effectively in a stochastic manner     

Independent Component Analysis by Using Joint Cumulants and its Application to Remote Sensing Images

In this paper, a joint cumulant independent component analysis (JC-ICA) algorithm is presented. It utilizes the higher order joint cumulants to extract independent components and can be implemented efficiently by a neural network. Its application in SAR (synthetic aperture radar) image analysis is presented and a comparison is also made with two other ICA methods. The results show the usage in image analysis and separation. Because the algorithm is based on statistics of order higher than the second, it is suitable also for applications to data with non-Gaussian distributions in blind signal processing.     

A Markov model for blind image separation by a mean-field EM algorithm.

This paper deals with blind separation of images from noisy linear mixtures with unknown coefficients, formulated as a Bayesian estimation problem. This is a flexible framework, where any kind of prior knowledge about the source images and the mixing matrix can be accounted for. In particular, we describe local correlation within the individual images through the use of Markov random field (MRF) image models. These are naturally suited to express the joint pdf of the sources in a factorized form, so that the statistical independence requirements of most independent component analysis approaches to blind source separation are retained. Our model also includes edge variables to preserve intensity discontinuities. MRF models have been proved to be very efficient in many visual reconstruction problems, such as blind image restoration, and allow separation and edge detection to be performed simultaneously. We propose an expectation-maximization algorithm with the mean field approximation to derive a procedure for estimating the mixing matrix, the sources, and their edge maps. We tested this procedure on both synthetic and real images, in the fully blind case (i.e., no prior information on mixing is exploited) and found that a source model accounting for local autocorrelation is able to increase robustness against noise, even space variant. Furthermore, when the model closely fits the source characteristics, independence is no longer a strict requirement, and cross-correlated sources can be separated, as well.     

基于APSO的盲源分离算法在盲图像分离中的应用

利用独立分量分析(ICA)的自适应粒子群(APSO)算法对因传输等过程而引起的多幅灰度图像混叠进行盲分离,针对图像盲分离提出了一种基于改进的APSO的盲源分离算法并将其应用于分离模糊灰度图像。利用峰度和负熵分别作为粒子群算法的第一和第二适应度函数根据其高斯性原理作为独立性判别标准对分离矩阵进行自适应更新。分析比较不同盲分离算法对图像分离的收敛性,仿真结果证明改进的自适应粒子群算法能够很好地分离图像且计算性能指标优越,收敛效果好。     

Temporal BYY learning for state space approach, hidden Markovmodel, and blind source separation

The temporal Bayesian Yang-Yang (TBYY) learning has been presented for signal modeling in a general state space approach, which provides not only a unified point of view on the Kalman filter, hidden Markov model (HMM), independent component analysis (ICA), and blind source separation (BSS) with extensions, but also further advances on these studies, including a higher order HMM, independent HMM for binary BSS, temporal ICA (TICA), and temporal factor analysis for real BSS without and with noise. Adaptive algorithms are developed for implementation and criteria are provided for selecting an appropriate number of states or sources. Moreover, theorems are given on the conditions for source separation by linear and nonlinear TICA. Particularly, it has been shown that not only non-Gaussian but also Gaussian sources can also be separated by TICA via exploring temporal dependence. Experiments are also demonstrated     

基于鲁棒主成分分析的多域联合杂波抑制算法

奇异值分解等传统算法在处理穿墙成像中的杂波抑制问题时,杂波消除不够彻底,目标成像质量不高,严重影响后续的目标检测与识别。为解决这一问题,该文基于鲁棒主成分分析理论,在回波域和图像域分别建立联合低秩稀疏模型,以光滑化快速交替线性化(SFAL)方法来求解模型,并对目标图像进行指数加权联乘多域图像融合处理,从而得到最终成像结果。仿真结果表明,该算法速度快、精度高,可有效改善目标成像质量,并能较好地满足穿墙成像的实时性和准确性要求。     

Two Dimensional Spatial Independent Component Analysis and Its Application in fMRI Data Process

One important application of independent component analysis （ICA） is in image processing. A two dimensional （2-D） composite ICA algorithm framework for 2-D image independent component analysis （2-D ICA） is proposed. The 2-D nature of the algorithm provides it an advantage of circumventing the roundabout transforming procedures between two dimensional （2-D） image deta and one-dimensional （l-D） signal. Moreover the combination of the Newton （fixed-point algorithm） and natural gradient algorithms in this composite algorithm increases its efficiency and robustness. The convincing results of a successful example in functional magnetic resonance imaging （fMRI） show the potential application of composite 2-D ICA in the brain activity detection.     

Adaptive nonlinear PCA algorithms for blind source separation without prewhitening

Blind source separation (BSS) aims at recovering statistically independent source signals from their linear mixtures without knowing the mixing coefficients. Besides independent component analysis, nonlinear principal component analysis (NPCA) is shown to be another useful tool for solving this problem, but it requires that the measured data be prewhitened. By taking into account the autocorrelation matrix of the measured data, we present in this paper a modified NPCA criterion, and develop a least-mean-square (LMS) algorithm and a recursive least-squares algorithm. They can perform the online BSS using directly the unwhitened observations. Since a natural gradient learning is applied and the prewhitening process is removed, the proposed algorithms work more efficiently than the existing NPCA algorithms, as verified by computer simulations on man-made sources as well as practical speech signals.     

Complex ICA of Brain Imaging Data [Life Sciences]

This paper discusses the advantages of independent component analysis over traditional model based data analysis techniques, e.g. linear regression and its applications to functional magnetic resonance imaging (fMRI).     

一种高分辨率ITO线路缺陷检测系统

为了满足微米量级氧化铟锡线路检测的需求,提出了一种高分辨率的用于检测氧化铟锡线路缺陷的检测系统,其检测精度可达2m.采用高分辨率线阵CCD相机以及中长焦镜头以获得较高的图像放大率与图像精度;通过分离相机与镜头及镜头倒置以获得较大的动态范围和较好的调制转换函数优化值;采用直线电机提高系统的运动精度与稳定度;同时采用大理石底座以减小周围环境的振动等对系统精度的影响.通过具体分析系统精度与速度要求,再考虑现场环境,对不同结构系统的优劣势进行了研究与论证.结果表明,该系统具有精度高、稳定性高、操作灵活等显著特点.