基于PCA和ICA的虹膜识别方法

为了提高虹膜识别的正确率,提出了利用主成分分析(PCA)与独立成分分析(ICA)相结合的方法,来对虹膜进行识别的方法。用该方法进行虹膜识别时,首先对预处理后的虹膜图像,利用PCA算法进行去二阶相关和降维处理;然后再进行ICA训练。ICA训练采用了以下两种方法:方法1,将参与ICA训练的图像看作是随机变量,而将图像中的像素值看作是随机实验结果,ICA训练后即可得到相互独立的ICA虹膜基图像;方法2,将图像中的像素值看作是随机变量,而将图像看作是随机实验结果,ICA训练后即得到相互独立的ICA系数。采用CASIA虹膜数据库进行的试验结果表明,基于PCA和ICA的虹膜识别算法在两种训练方式下的正确识别率分别达到98.89%和98.33%。     

基于大间距准则的不相关保局投影分析

局部保持投影(Locality preserving projections,LPP)算法只保持了目标在投影后的邻域局部信息,为了更好地刻画数据的流形结构, 引入了类内和类间局部散度矩阵,给出了一种基于有效且稳定的大间距准则(Maximum margin criterion,MMC)的不相关保局投影分析方法.该方法在最大化散度矩阵迹差时,引入尺度因子α,对类内和类间局部散度矩阵进行加权,以便找到更适合分类的子空间并且可避免小样本问题; 更重要的是,大间距准则下提取的判别特征集一般情况下是统计相关的,造成了特征信息的冗余, 因此,通过增加一个不相关约束条件,利用推导出的公式提取不相关判别特征集, 这样做, 对正确识别更为有利.在Yale人脸库、PIE人脸库和MNIST手写数字库上的测试结果表明,本文方法有效且稳定, 与LPP、LDA (Linear discriminant analysis)和LPMIP(Locality-preserved maximum information projection)方法等相比,具有更高的正确识别率.     

Face recognition by independent component analysis

A number of current face recognition algorithms use face representations found by unsupervised statistical methods. Typically these methods find a set of basis images and represent faces as a linear combination of those images. Principal component analysis (PCA) is a popular example of such methods. The basis images found by PCA depend only on pairwise relationships between pixels in the image database. In a task such as face recognition, in which important information may be contained in the high-order relationships among pixels, it seems reasonable to expect that better basis images may be found by methods sensitive to these high-order statistics. Independent component analysis (ICA), a generalization of PCA, is one such method. We used a version of ICA derived from the principle of optimal information transfer through sigmoidal neurons. ICA was performed on face images in the FERET database under two different architectures, one which treated the images as random variables and the pixels as outcomes, and a second which treated the pixels as random variables and the images as outcomes. The first architecture found spatially local basis images for the faces. The second architecture produced a factorial face code. Both ICA representations were superior to representations based on PCA for recognizing faces across days and changes in expression. A classifier that combined the two ICA representations gave the best performance.     

A novel hybrid approach based on sub-pattern technique and whitened PCA for face recognition

Recently, in a task of face recognition, some researchers presented that independent component analysis (ICA) Architecture I involves a vertically centered principal component analysis (PCA) process (PCA I) and ICA Architecture II involves a whitened horizontally centered PCA process (PCA II). They also concluded that the performance of ICA strongly depends on its involved PCA process. This means that the computationally expensive ICA projection is unnecessary for further process and involved PCA process of ICA, whether PCA I or II, can be used directly for face recognition. But these approaches only consider the global information of face images. Some local information may be ignored. Therefore, in this paper, the sub-pattern technique was combined with PCA I and PCA II, respectively, for face recognition. In other words, two new different sub-pattern based whitened PCA approaches (which are called Sp-PCA I and Sp-PCA II, respectively) were performed and compared with PCA I, PCA II, PCA, and sub-pattern based PCA (SpPCA). Then, we find that sub-pattern technique is useful to PCA I but not to PCA II and PCA. Simultaneously, we also discussed what causes this result in this paper. At last, by simultaneously considering global and local information of face images, we developed a novel hybrid approach which combines PCA II and Sp-PCA I for face recognition. The experimental results reveal that the proposed novel hybrid approach has better recognition performance than that obtained using other traditional methods.     

应用复小波和独立成分分析的人脸识别

结合双树复小波变换（DT-CWT）和独立成分分析（ICA）提出了一种人脸识别新方法。该方法首先应用双树复小波变换提取图像的特征向量,接着通过主成分分析（PCA）降低特征向量的维数,在此基础上应用独立成分分析提取统计上独立的特征向量,然后基于相关系数的分类器对特征向量进行分类。双树复小波变换具有方向与尺度选择性,并能有效的保持图像的频域信息,其与独立成分分析相结合提取的特征具有良好的分类性能。在ORL和AR人脸图像数据库上进行算法验证的结果表明该方法的有效性。     

A Direct Locality Preserving Projections (DLPP) Algorithm for Image Recognition

This paper proposes a novel locality preserving projections (LPP) algorithm for image recognition, namely, the direct locality preserving projections (DLPP), which directly optimizes locality preserving criterion on high-dimensional raw images data via simultaneous diagonalization, without any dimensionality reduction preprocessing. Our algorithm is a direct and complete implementation of LPP. Experimental results on the PolyU palmprint database and ORL face database show the effectiveness of the proposed algorithm.     

基于核独立成分分析的人脸识别研究

在人脸识别中提出一种基于非线性子空间的核独立成分分析(KICA)方法。在简单介绍了ICA方法的基础上,对KICA方法的基本原理和算法作了较为详细的描述。为了验证基于KICA和ICA的人脸识别方法的识别效果,进行了对比实验和分析。实验和分析结果表明,在人脸识别中,基于KICA的方法优于基于ICA的方法。     

完备鉴别保局投影人脸识别算法

为了充分利用保局总体散布主元空间内的鉴别信息进行人脸识别,提出了一种完备鉴别保局投影(complete discriminant locality preserving projections,简称CDLPP)人脸识别算法.鉴于Fisher鉴别分析和保局投影已经被广泛的应用于人脸识别,完备鉴别保局投影(locality preserving projections,简称LPP)算法将这两者结合起来,分析了保局类内散布、类间散布和总体散布的主元空间和零空间内包含的鉴别信息.该算法采用奇异值分解(singular value decomposition,简称SVD),去除了不含任何鉴别信息的保局总体散布的零空间;分别在保局类内散布的主元空间和零空间提取规则鉴别特征和不规则鉴别特征;用串联的方式在特征层融合规则鉴别特征和不规则鉴别特征形成完备的鉴别特征进行人脸识别.在ORL库、FERET子库和PIE子库上的大量识别实验充分表明了完备鉴别保局投影算法的性能优于线性鉴别分析、保局投影和鉴别保局投影等现有的子空间人脸识别算法,验证了算法的有 效性.     

基于SLPP和张量分解相结合的人脸识别*

针对多线性分析算法对多姿态多身份因素并存时,人脸的识别率大大下降等问题,提出了带监督的局 部保留投影映射算法与多线性张量分析算法相结合的人脸识别方法。该方法将人脸转动的近邻点信息作为监 督信息引入,更精确地描述了姿态空间的非线性结构,再结合张量分解和核函数将姿态流形系数映射到高维图 像空间,使得从低维空间到高维空间映射的精确性得以提高。在东方人脸数据库上进行实验,结果验证了该算 法的有效性。     

Improved support vector classification using PCA and ICA feature space modification

An approach that unifies subspace feature selection and optimal classification is presented. Independent component analysis (ICA) and principal component analysis (PCA) provide a maximally variant or statistically independent basis for pattern recognition. A support vector classifier (SVC) provides information about the significance of each feature vector. The feature vectors and the principal and independent component bases are modified to obtain classification results which provide lower classification error and better generalization than can be obtained by the SVC on the raw data and its PCA or ICA subspace representation. The performance of the approach is demonstrated with artificial data sets and an example of face recognition from an image database.     

稀疏保持典型相关分析及在特征融合中的应用

稀疏保持投影(Sparsity preserving projections, SPP)由于保持了数据间的稀疏重构性, 因而获取的投影向量满足旋转、尺度和平移的不变性, 并能够在无标签的情况下提取样本的自然鉴别信息, 在人脸识别领域取得了较为成功的应用. 本文在典型相关分析(Canonical correlation analysis, CCA)的基础上引入稀疏保持项, 提出一种稀疏保持典型相关分析(Sparsity preserving canonical correlation analysis, SPCCA). 该方法不仅实现了两组特征集鉴别信息的有效融合, 同时对提取特征间的稀疏重构性加以约束, 增强了特征的表示和鉴别能力. 在多特征手写体字符集与人脸数据集上的实验结果表明, SPCCA比CCA具有更优的识别性能.     

一种新的多人脸检测方法研究

自动人脸检测是人脸识别系统的一个重要部分,本文提出了一种新的基于独立成分分析（ICA）和多项式神经网络（PNN）相结合的人脸检测方法,该方法首先在训练样本中使用ICA分离出代表人脸和非人脸特征子空间的独立影像基,把训练图像映射到该子空间降维后作为PNN网络的输入训练网络;对测试图像采用移动多尺度窗口提取图像模式,采用ICA降维后输入PNN网络,进而分类检测出人脸和非人脸。算法通过CMU-MIT的复杂背景人脸库中的多人脸图像进行实验,得到很高的检测率和较低的误检率.     

人耳人脸特征融合在身份鉴别中的研究

针对单一人耳识别对姿态变化鲁棒性较差的问题,鉴于人脸在图像性质和生理位置上与人耳具有相似性和互补性,使用了多模态特征融合的方法提高姿态变化下的识别率.与传统的独立成分分析首先获得独立的基向量(ICAl)不同,提出了利用ICA直接获得独立的鉴剐特征的方法(ICA2).在USTB图像库上分别将两种ICA特征进行单模态和多模态的融合.实验表明,两种特征的融合提高了单一模态的识别率,并且多模态识别优于单一的人耳或人脸识别.     

Facial expression recognition based on two-dimensional discriminant locality preserving projections

In this paper, a novel method called two-dimensional discriminant locality preserving projections (2D-DLPP) is proposed. By introducing between-class scatter constraint and label information into two-dimensional locality preserving projections (2D-LPP) algorithm, 2D-DLPP successfully finds the subspace which can best discriminate different pattern classes. So the subspace obtained by 2D-DLPP has more discriminant power than 2D-LPP, and is more suitable for recognition tasks. The proposed method was applied to facial expression recognition tasks on JAFFE and Cohn-Kanade database and compared with other three widely used two-dimensional methods: 2D-PCA, 2D-LDA and 2D-LPP. The high recognition rates show the effectiveness of the proposed algorithm.     

Ensemble learning for independent component analysis

It is well known that the applicability of independent component analysis (ICA) to high-dimensional pattern recognition tasks such as face recognition often suffers from two problems. One is the small sample size problem. The other is the choice of basis functions (or independent components). Both problems make ICA classifier unstable and biased. In this paper, we propose an enhanced ICA algorithm by ensemble learning approach, named as random independent subspace (RIS), to deal with the two problems. Firstly, we use the random resampling technique to generate some low dimensional feature subspaces, and one classifier is constructed in each feature subspace. Then these classifiers are combined into an ensemble classifier using a final decision rule. Extensive experimentations performed on the FERET database suggest that the proposed method can improve the performance of ICA classifier.     

基于鉴别稀疏保持嵌入的人脸识别算法

鉴于近年来稀疏表示（Sparse representation,SR）在高维数据例如人脸图像的特征提取与降维领域的快速发展,对原始的稀疏保持投影（Sparsity preserving projection,SPP）算法进行了改进,提出了一种叫做鉴别稀疏保持嵌入（Discriminant sparsity preserving embedding,DSPE）的算法. 通过求解一个最小二乘问题来更新SPP中的稀疏权重并得到一个更能真实反映鉴别信息的鉴别稀疏权重,最后以最优保持这个稀疏权重关系为目标来计算高维数据的低维特征子空间.该算法是一个线性的监督学习算法,通过引入鉴别信息,能够有效地对高维数据进行降维. 在ORL库、Yale库、扩展Yale B库和CMU PIE库上的大量实验结果验证了算法的有效性.     

块独立成分分析的人脸识别

针对利用ICA提取人脸特征时需要将人脸图像转换成向量，导致空间维数很高以及不能准确地估计特征等问题，提出了一种新的独立子空间人脸识别算法——块独立成分分析（B-ICA）。和经典的ICA相比，B-ICA算法把人脸图像划分成一些互不重叠的子块，然后把每个子块转换成向量，看成是低维空间中的训练点（训练向量）。因此在B-ICA算法中，样本的维数比ICA算法中样本的维数低，降低了维数灾难（即样本的训练个数远小于样本的维数）造成的错误识别率。在Yale和AR数据库上进行了大量仿真实验，实验结果表明B-ICA算法的识别率比ICA和其他一些子空间算法的识别率高。     

基于分块核主元分析的人脸识别方法研究

传统的基于数据二阶统计矩的主元分析法（PCA）是一种有效的数据特征提取方法,是基于原始特征的一种线性变换。但是,当原始数据中存在非线性属性时,用主元分析法后留下的显著成分就可能不再反映这种非线性属性。而核主元分析则是基于原始数据的高阶统计量,是一种非线性变换,在图像识别中它可以描述多个像素之间的相关性。而KPCA方法只考虑了人脸图像的整体信息,没有考虑到局部特征信息。文章提出了分块核主元分析（MKPCA）的方法进行人脸识别,取得了很好的效果。     

核主元分析及其在人脸识别中的应用

传统的基于数据二阶统计矩的特征脸法(Eigenface)或主元分析法(PCA)是一种有效的数据特征提取方法，是基于原始特征的一种线性变换。但是，当原始数据中存在非线性属性时，用主元分析法后留下的显著成分就可能不再反映这种非线性属性。而核主元分析则是基于原始数据的高阶统计量，是一种非线性变换，在图像识别中它可以描述多个像素之间的相关性。该文采用KPCA法提取人脸特征，利用线性支持向量机设计分类器，实验结果表明，基于核主元分析方法的识别正确率明显优于基于主元分析法。     

基于ICA和NFL分类的局部人脸识别方法

目前已存在很多基于统计的人脸整体识别方法，独立元分析方法就是一种基于信号高阶统计特性的方法。但由于人脸光照、姿态、信息缺损等外部不可避免因素会引起整个人脸灰度图像产生很大的变化，因而会对这类整体统计性方法的稳定性产生很大影响。为此提出了一种基于独立元分析和最近邻特征线的局部人脸识别方法。首先，通过对人眼的手工定位并依据人脸几何特征完成对人脸图像的截取和局部分块，从而移除发型等无用信息；然后对每个局部图像进行PCA／ICA特征提取；最后的识别阶段，通过最近邻特征线方法得到各自识别距离，并通过对各部分设置合理的权重来综合判定。实验结果表明，作为一种有效的识别方法，分块独立元方法在识别率、识别的稳定性、应用的灵活性等方面都优于传统的整体识别方法。