多流形判别分析在人脸识别中的研究

局部保持投影LPP(Locality Preserving Projection)是一种有效的非线性降维方法,能够使投影降维后的数据与原输入空间中的相似局部结构保持一致,但是该方法没有充分利用类间样本点的权重等重要信息。为了解决这个问题,提出基于Fisher准则的多流形判别分析FMMDA(Fisher Multi-Manifold Discriminant Analysis)方法。结合Fisher准则训练样本类内拉普拉斯图和样本均值类间拉普拉斯图,既保持了原样本的相似局部结构,又充分地利用了不同类别之间的权重。在ORL及Yale人脸库上验证了该方法的有效性。与其他几种最先进的方法相比,FMMDA方法取得了更好的识别效果。     

HOG和多流形判别分析相融合的人脸识别

为了提高人脸的识别率,提出一种方向梯度直方图和多流形判别分析相融合的人脸识别算法。将一幅图像划分为多个子块图像块,并采用方向梯度直方图算法对每一个小块进行处理;采用多流形判别分析提取特征,并采用最小二乘支持向量机建立分类器对人脸进行分类和识别;在Yale和AR人脸库进行仿真实验。实验结果表明,相对于传统人脸别算法,该算法不仅提高了人脸识别率和识别速度,并且对光照和姿态变化具有较强的鲁棒性。     

基于格拉斯曼流形子空间融合的多视图聚类

现有的多视图聚类算法大多假设多视图数据点之间为线性关系,且在学习过程中无法保留原始特征空间的局部性;而在欧氏空间中进行子空间融合又过于单调,无法将学习到的子空间表示对齐。针对以上问题,提出了基于格拉斯曼流形融合子空间的多视图聚类算法。首先,将核技巧和局部流形结构学习结合以得到不同视图的子空间表示;然后,在格拉斯曼流形上融合这些子空间表示以得到一致性亲和矩阵;最后,对一致性亲和矩阵执行谱聚类来得到最终的聚类结果,并利用交替方向乘子法（ADMM）来优化所提模型。与核多视图低秩稀疏子空间聚类（KMLRSSC）算法相比,所提算法的聚类精度在MSRCV1、Prokaryotic、Not-Hill数据集上分别提高了20.83个百分点、9.47个百分点和7.33个百分点。实验结果验证了基于格拉斯曼流形融合子空间的多视图聚类算法的有效性和良好性能。     

基于格拉斯曼流形上谱聚类的视频人脸识别

针对传统的三维(3D)人脸识别算法仅考虑特征提取而不能很好地运用于实际视频人脸识别系统的问题,提出一种基于格拉斯曼流形谱聚类的动态3D视频全自动识别系统。首先通过去除孤立点、均匀采样、剪裁、姿势纠正等过程将3D视频数据集进行规范化;然后从训练视频的不同位置提取出可变长度的局部视频片段,使用基于谱聚类的高效算法将其表示为格拉斯曼流形上的点;最后,将所得到的聚类中心和测试视频中的点相匹配,并且利用基于表决的策略来完成测试视频的人脸识别。在大型通用3D视频数据库BU4DFE上的实验验证了该算法的有效性。实验结果表明,与几种较为先进的视频人脸识别算法相比,该算法取得了更好的识别效果。     

面向相交多流形聚类的标签传播算法

经典的流形学习算法假设样本数据位于高维单流形上,但在现实生活中的真实数据通常位于高维多流形上,且这些数据往往相互交叠,导致流形学习算法效果不佳。传统的标签传播算法通过相似性矩阵构建连接矩阵,实现良好分离数据的聚类,但不能有效聚类相互交叠的多流形数据。针对该问题,提出一种面向相交多流形的标签传播算法LPAMMC。采用局部主成分分析算法确定相交多流形数据的相交区域,并基于混合概率主成分分析(MPPCA)模型和多流形的拓扑结构划分相互交叠的子流形,构建“must-link”和“cannot-link”聚类约束,通过约束构建适合相交多流形数据的传播矩阵,实现标签传播算法。LPAMMC算法通过MPPCA模型和多流形拓扑结构划分出子流形,提高相交多流形数据的聚类精度,且MPPCA模型仅用于多流形数据的相交区域,降低了计算复杂度。实验结果表明,LPAMMC算法不仅具有标签传播算法速度快的特点,且能有效聚类相交多流形数据。在Two spirals数据集上的聚类精度、标准互信息和调整兰德系数取得了与SMMC算法相同的性能,运行时间缩短86.7个百分点。     

PID参数调节的谱多流形聚类算法研究

数据的复杂和多样性使得对大数据处理和分析能力有更高的要求。流形聚类在数据挖掘中取得显著的成功,但参数调整是聚类算法研究中的难点之一,直接影响聚类性能。传统的聚类算法参数调节一般依赖于经验,或者因参数调节的盲目性和随机性,而使得算法失效或复杂度较高。提出了一种基于比例-积分-微分(PID)控制约束的主动控制机制,约束谱多流形聚类参数调整的新方法。通过构造相似度矩阵,使用多个主成分分析器来估计局部切线空间。模型逼近过程由参数传递和PID调节控制。在调整过程中,采用三维ZN方法调整模型参数,扩展搜索空间,根据反馈结果控制谱多流形聚类过程,提高了算法的准确性和复杂性。通过在合成和实际中的不同类型的数据特征集进行检验,可以获得更好的聚类性能。     

基于虚拟样本图像集的多流形鉴别学习算法

为了丰富训练样本的类内变化信息,提出了基于通用训练样本集的虚拟样本生成方法。进一步,为了利用生成的虚拟样本中的类内变化信息有效地完成单样本人脸识别任务,提出了基于虚拟样本图像集的多流行鉴别学习算法。该算法首先将每类仅有的单个训练样本图像和该类的虚拟样本图像划分为互补重叠的局部块并构建流形,然后为每个流形学习一个投影矩阵,使得相同流形内的局部块在投影后的低维特征空间间隔最小化,不同流形中的局部块在投影后的低维特征空间中间隔最大化。实验结果表明,所提算法能够准确地预测测试样本中的类内变化,是一种有效的单样本人脸识别算法。     

基于图像分块和特征选择的单训练样本人脸识别

为了提高人脸识别的正确率,针对单样本人脸识别训练样本存在的缺陷,提出一种基于图像分块和特征选择的单样本人脸识别算法。首先将人脸图像划分成子块,并分别提取各子块的特征,连接成人脸图像特征向量,然后采用多流形判断分析算法选择对人脸识别结果贡献较大的特征。最后计算采用支持向量机对人脸进行识别,并采用Yale B和PIE人脸库对本文人脸算法的有效性和优越性进行仿真测试。仿真结果表明,相对于当前典型人脸识别算法,该算法提高了人脸识别正确率,获得了更加理想的人脸识别效果。     

基于随机分块的稀疏子空间聚类方法

针对稀疏子空间聚类（SSC）方法聚类误差大的问题,提出了基于随机分块的SSC方法。首先,将原问题数据集随机分成几个子集,构建几个子问题;然后,采用交替方向乘子法（ADMM）分别求得几个子问题的系数矩阵,之后将几个系数矩阵扩充成与原问题一样大小的系数矩阵,并整合成一个系数矩阵;最后,根据整合得到的系数矩阵计算得到一个相似矩阵,并采用谱聚类（SC）算法获得原问题的聚类结果。相较于稀疏子空间聚类（SSC）、随机稀疏子空间聚类（S³COMP-C）、基于正交匹配追踪的稀疏子空间聚类（SSCOMP）、谱聚类（SC）和K均值（K-Means）算法中的最优算法,基于随机分块的SSC方法将子空间聚类误差平均降低了3.12个百分点,且其互信息、兰德指数和熵3个性能指标都明显优于对比算法。实验结果表明基于随机分块的SSC方法能降低子空间聚类误差,改善聚类性能。     

流形正则引导的自适应加权多视角子空间聚类

现有多视角子空间聚类方法大多学习多视角数据的一致共享信息,并将每个视角的贡献视为同等重要以集成多个视角的差异信息.然而此思想忽略不同视角间可能存在的噪声或冗余,导致最终聚类性能不佳.为此,文中提出流形正则引导的自适应加权多视角子空间聚类算法.算法采用核范数学习每个视角的一致性全局低秩表示信息并利用组效应刻画不同视角的差异信息.根据流形正则的思想,自适应学习每个视角的权重,自动为每个视角的差异信息分配贡献度.再根据自适应权重集成差异信息并融合一致信息,获得最终的共识表示.最后利用该共识表示实现聚类.在6个公开数据集上的实验表明文中算法能有效提升多视角聚类性能.     

单样本人脸识别线性回归分类

对线性回归分类器在单样本人脸识别中的应用进行研究,提出使用稀疏表示结合线性回归分类的方法对单样本人脸进行识别,并对该方法进行分析和评论。计算单个训练样本在辅助样本集上的稀疏表示,选出和训练样本近邻的几个人脸,计算这些样本的类内变化,将它们和训练样本一起构成人脸模型,使用线性回归分类器进行分类。在AR和FERET人脸库上的实验验证了该方法的有效性。     

一种自适应加权SpPCA单样本人脸识别算法

子模式主成分分析(SpPCA)算法忽略了人脸不同分块应该具有不同的重要性.为了解决此问题,提出一种自适应加权SpPCA单样本人脸识别算法,对人脸图像的不同分块自适应地计算其权重.算法对人脸进行分块,按照SpPCA算法将各个分块投影到特征脸的基坐标上,并以每个模块LBP编码的纹理图像信息熵来表征该模块的权值;将模块的权重赋予该模块的特征脸投影,并得到最终分类结果.实验在Yale B和扩展Yale B人脸数据集上进行测试.实验表明,该算法得到了较好的识别结果,有效地弥补了SpPCA算法的不足.     

On solving the face recognition problem with one training sample per subject

The lack of adequate training samples and the considerable variations observed in the available image collections due to aging, illumination and pose variations are the two key technical barriers that appearance-based face recognition solutions have to overcome. It is a well-documented fact that their performance deteriorates rapidly when the number of training samples is smaller than the dimensionality of the image space. This is especially true for face recognition applications where only one training sample per subject is available. In this paper, a recognition framework based on the concept of the so-called generic learning is introduced as an attempt to boost the performance of traditional appearance-based recognition solutions in the one training sample application scenario. Different from contemporary approaches, the proposed solution learns the intrinsic properties of the subjects to be recognized using a generic training database which consists of images from subjects other than those under consideration. Many state-of-the-art face recognition solutions can be readily integrated in the proposed framework. A novel multi-learner framework is also proposed to further boost recognition performance.Extensive experimentation reported in the paper suggests that the proposed framework provides a comprehensive solution and achieves lower error recognition rate when considered in the context of one training sample face recognition problem.     

Intrapersonal subspace analysis with application to adaptive Bayesian face recognition

We propose a subspace distance measure to analyze the similarity between intrapersonal face subspaces, which characterize the variations between face images of the same individual. We call the conventional intrapersonal subspace the average intrapersonal subspace (AIS) because the image differences often come from a large number of persons. We call an intrapersonal subspace specific intrapersonal subspace (SIS) if the image differences are from just one person. We demonstrate that SIS varies from person to person and most SISs are not similar to AIS. Based on these observations, we introduce the maximum a posteriori (MAP) adaptation to the problem of SIS estimation, and apply it to the Bayesian face recognition algorithm. Experimental results show that the adaptive Bayesian algorithm outperforms the non-adaptive Bayesian algorithm as well as Eigenface and Fisherface methods when a small number of adaptation images are available.     

Subspace distance analysis with application to adaptive Bayesian algorithm for face recognition

We propose subspace distance measures to analyze the similarity between intrapersonal face subspaces, which characterize the variations between face images of the same individual. We call the conventional intrapersonal subspace average intrapersonal subspace (AIS) because the image differences often come from a large number of persons. An intrapersonal subspace is referred to as specific intrapersonal subspace (SIS) if the image differences are from just one person. We demonstrate that SIS varies significantly from person to person, and most SISs are not similar to AIS. Based on these observations, we introduce the maximum a posteriori (MAP) adaptation to the problem of SIS estimation, and apply it to the Bayesian face recognition algorithm. Experimental results show that the adaptive Bayesian algorithm outperforms the non-adaptive Bayesian algorithm as well as Eigenface and Fisherface methods if a small number of adaptation images are available.     

Multi-resolution feature fusion for face recognition

For face recognition, image features are first extracted and then matched to those features in a gallery set. The amount of information and the effectiveness of the features used will determine the recognition performance. In this paper, we propose a novel face recognition approach using information about face images at higher and lower resolutions so as to enhance the information content of the features that are extracted and combined at different resolutions. As the features from different resolutions should closely correlate with each other, we employ the cascaded generalized canonical correlation analysis (GCCA) to fuse the information to form a single feature vector for face recognition. To improve the performance and efficiency, we also employ “Gabor-feature hallucination”, which predicts the high-resolution (HR) Gabor features from the Gabor features of a face image directly by local linear regression. We also extend the algorithm to low-resolution (LR) face recognition, in which the medium-resolution (MR) and HR Gabor features of a LR input image are estimated directly. The LR Gabor features and the predicted MR and HR Gabor features are then fused using GCCA for LR face recognition. Our algorithm can avoid having to perform the interpolation/super-resolution of face images and having to extract HR Gabor features. Experimental results show that the proposed methods have a superior recognition rate and are more efficient than traditional methods.     

基于图像分块的LDA人脸识别

设计了一种基于图像分块的LDA(linear discriminant analysis)人脸识别方法,该方法从模式的原始数字图像出发,先对图像矩阵进行分块,然后对分块子图像进行LDA特征提取,从而得到能代替原始模式的低维新模式,最后再用最小距离分类器进行分类.该方法克服了传统LDA方法的缺点,其优点是能有效地提取图像的局部特征.实验表明:该方法在识别性能上优于Fisheffaces方法.     

一个人脸识别系统的设计与实现

设计了一个在区分人脸朝向的基础上,再进行人脸辨别的识别系统。把BP网络用于人脸朝向的识别,并且用一组单输出的子网络代替原来的BP网络,提高了人脸朝向的识别率。在人脸朝向的分类基础上,用主元分析法进行人脸识别。实验结果表明此系统提高了人脸的识别率。     

Making FLDA applicable to face recognition with one sample per person

In face recognition, the Fisherface approach based on Fisher linear discriminant analysis (FLDA) has obtained some success. However, FLDA fails when each person just has one training face sample available because of nonexistence of the intra-class scatter. In this paper, we propose to partition each face image into a set of sub-images with the same dimensionality, therefore obtaining multiple training samples for each class, and then apply FLDA to the set of newly produced samples. Experimental results on the FERET face database show that the proposed approach is feasible and better in recognition performance than E(PC)²A.