基于模糊核Fisher判别的说话人识别

在深入研究核Fisher判别方法的基础上,提出一种新的模糊核Fisher判别算法应用于说话人识别。采用模糊C均值聚类方法选择样本数据的同时,得到样本的模糊隶属度矩阵和聚类中心向量,进而对核Fisher判别算法中的类间离散度矩阵和类内离散度矩阵进行改进,生成模糊核Fisher判别算法,将其应用于说话人语音识别。     

核参数判别选择方法在核主元分析中的应用

针对核主元分析(KPCA)中高斯核参数β的经验选取问题,提出了核主元分析的核参数判别选择方法。依据训练样本的类标签计算类内、类间核窗宽,在以上核窗宽中经判别选择方法确定核参数。根据判别选择核参数所确定的核矩阵,能够准确描述训练空间的结构特征。用主成分分析(PCA)对特征空间进行分解,提取主成分以实现降维和特征提取。判别核窗宽方法在分类密集区域选择较小窗宽,在分类稀疏区域选择较大窗宽。将判别核主成分分析(Dis-KPCA)应用到数据模拟实例和田纳西过程(TEP),通过与KPCA、PCA方法比较,实验结果表明,Dis-KPCA方法有效地对样本数据降维且将三个类别数据100%分开,因此,所提方法的降维精度更高。     

改进的基于核密度估计的数据分类算法

目前,很多基于核密度估计的数据分类算法采用的判别规则忽视了不平衡类问题.对此,提出了改进的基于核密度估计的数据分类算法.该算法可处理不平衡类带来的影响,并在不平衡类问题严重时也能发挥好的效果,而且可以推广到多分类问题.实验结果表明了这种改进是非常有效的,它提高了基于核密度估计的分类算法对不平衡类的适应力.     

核函数的性质及其构造方法

支持向量机是一项机器学习技术,发展至今近10年了,已经成功地用于模式识别、回归估计以及聚类等,并由此衍生出了核方法。支持向量机由核函数与训练集完全刻画。进一步提高支持向量机性能的关键,是针对给定的问题设计恰当的核函数,这就要求对核函数本身有深刻了解。本文首先分析了核函数的一些重要性质,接着对3类核函数,即平移不变核函数、旋转不变核函数和卷积核,提出了简单实用的判别准则。在此基础上,验证和构造了很多重要核函数。     

核正交判别局部正切空间对齐算法

针对现有的局部正切空间算法中存在的问题,文中提出一种基于核变换的特征提取方法——核正交判别局部正切空间对齐算法(KOTSDA)。该算法首先利用核方法将人脸图像投影到一个高维非线性空间,提取其非线性信息;然后在目标函数中利用正切空间判别分析算法在保持样本的类内局部几何结构的同时最大化类间差异;最后添加正交约束,得到核正交判别局部正切空间对齐算法。该算法不需要经过PCA降维,有效避免判别信息的丢失,在ORL和Yale人脸库上的实验验证算法有效性。     

基于PCA和核Fisher判别的说话人确认

针对核Fisher判别技术在说话人确认中实时性较差的问题,提出了一种基于PCA和核Fisher判别的说话人确认方法.利用PCA进行特征向量的降维、去冗余,以减少后续计算的复杂度,提高说话人确认的速度,使用基于核函数的Fisher判别技术对说话人进行确认,从而在整体上提高系统的实时性.并通过实验验证了该方法的有效性.     

基于KL和核Fisher判别的车位检测方法

提出一种基于KL变换和核Fisher判别的车位检测方法,对车位图像进行预处理,将该车位图像投影至已通过KL变换构造出的特征车位子空间中,得到的投影系数即为车位的特征向量,利用核Fisher判别进行车位占用情况的判别。仿真实验采用3种不同的核函数进行核Fisher判别比较,结果表明,采用高斯径向基核函数的车位检测判别方法检测的效果最佳,检测正确率高达97.6%。     

基于核Fisher的理想投影空间及分类阈值确定

介绍了一种基于Fisher线性判别的非线性分类方法--核Fisher,其主要思想是首先把样本映射到特征空间F,然后在此空问进行Fisher线性判别,隐含地实现了原输入空间的非线性判别;同时利用SVM对分类阚值进行估计,实现了对两类样本最大程度的区分.通过仿真可以得出这一判别方式有利于确定两类平均丢包率的区分阚值.     

基于量子遗传算法的XML聚类方法

主要用模式分析的核方法与量子遗传算法相结合研究XML聚类,提出了一种基于量子遗传算法混合核聚算法的XML文档聚类新方法。该方法先对XML文档约简,以频繁标签序列建立向量空间核的核矩阵,用高斯核函数求解初始聚类和聚类中心,然后用初始聚类中心构造量子遗传算法的初始种群,通过量子遗传算法与核聚算法相结合求得全局最优解的聚类。实验结果表明,使用该算法的聚类比改进的核聚算法、K均值算法等单一方法具有良好的收敛性、稳定性和更高的全局最优。     

基于判别核主元空间k近邻的批次过程监视

针对批次过程非线性、多模态等特征,提出一种基于判别核主元k近邻（Dis-kPCkNN）的故障检测方法。首先,在核主元分析（kPCA）中,高斯核的窗宽参数依据样本类别标签在类内窗宽和类间窗宽中判别选取,使得核矩阵能有效提取数据的关联特征,保持数据的类别信息;其次,在核主元空间中引用k近邻规则代替传统的T²统计方法,k近邻规则可以有效处理主元空间非线性和多模态等特征的故障检测问题。数值模拟实例和半导体蚀刻工艺过程仿真实验表明:基于判别核主元k近邻方法可以有效地处理具有非线性和多模态结构特征的故障检测问题,提高计算的效率,减少内存的占用,并且故障检测率明显优于传统方法。     

一种融合KPCA和KDA的人脸识别新方法

核判别分析（KDA）和核主成分分析（KPCA）分别是线性判别分析（LDA）和主成分分析（PCA）在核空间中的非线性推广,提出了一种融合KDA和KPCA的特征提取方法并应用于人脸识别中,该方法综合利用KDA和KPCA 的优点来提高人脸识别的性能。此外,还提出了一种广义最近特征线(GNFL)方法来构造有效的分类器。实验结果证明：提出的方法获得了更好的识别结果。     

Recursive “concave–convex” Fisher Linear Discriminant with applications to face,handwritten digit and terrain recognition

In classification, previous studies have shown that an eigenvalue based technique can be cast as an related SVM-type problem and that by solving this SVM-type problem, the performance can be improved significantly. In this paper, we develop a recursive “concave–convex” Fisher Linear Discriminant (DR) (RPFLD) for dimension reduction technique of high-dimensional data to extract as many meaningful features as possible, which incorporates the fundamental idea behind Fisher Linear Discriminant and casts the Fisher Linear Discriminant as a “concave–convex” programming problem based on the hinge loss. The solution of our method follows from solving the related SVM-type optimization problems iteratively, which means the proposed method, can be viewed as the combination of multiple related SVM-type problems. The special formulation of our method provides convenience for constructing sparse multi-class Fisher Linear Discriminant directly. Due to use of a recursive procedure, the number of features available from RPFLD is independent of the number of classes, meaning that in contrast to the original Fisher Linear Discriminant the number of features available from our method has no upper bound. We evaluate our algorithm on the Yale, and ORL face image databases, handwritten digit database and Terrain image dataset. Experimental results show that RPFLD outperforms other Fisher Linear Discriminant algorithms.     

Kernel-based improved discriminant analysis and its application to face recognition

Kernel discriminant analysis (KDA) is a widely used tool in feature extraction community. However, for high-dimensional multi-class tasks such as face recognition, traditional KDA algorithms have the limitation that the Fisher criterion is nonoptimal with respect to classification rate. Moreover, they suffer from the small sample size problem. This paper presents a variant of KDA called kernel-based improved discriminant analysis (KIDA), which can effectively deal with the above two problems. In the proposed framework, origin samples are projected firstly into a feature space by an implicit nonlinear mapping. After reconstructing between-class scatter matrix in the feature space by weighted schemes, the kernel method is used to obtain a modified Fisher criterion directly related to classification error. Finally, simultaneous diagonalization technique is employed to find lower-dimensional nonlinear features with significant discriminant power. Experiments on face recognition task show that the proposed method is superior to the traditional KDA and LDA.     

基于核Fisher判决分析的高性能多类分类算法

探讨了核Fisher判决分析算法(KernelFisherDiscriminantAnalysis,KFDA),并提出了一种基于KFDA的高性能多类分类算法。在进行多类分类时,首先通过一个非线性映射将训练样本映射到一个高维的核空间中,建立一个KFDA子空间,在该高维空间中,不同类别的样本之间的差异增大,同类样本聚集在一起,因此,在这个高维核空间中,就可以利用简单的最近邻法进行多类分类。实验结果表明,该算法在保证分类精度的条件下提高了分类器的训练和分类的速度。     

基于协作表示和模糊渐进最大边界嵌入的特征抽取方法

针对图嵌入方法在构造邻域关系图的过程中,简单地将样本数据划入某一类的做法并不妥当的问题,提出了模糊渐进的隶属度表示方法。该方法借助模糊数学的思想,通过模糊渐进的隶属度,将样本归属于不同类别。针对图嵌入方法中分类器效率偏低的问题,引入了协作表示分类方法,该分类方法大幅度提高了算法的计算效率。基于这两点,提出了基于协作表示和模糊渐进最大边界嵌入的特征抽取算法。在ORL、AR人脸数据库上,以及USPS数字手写体数据库上的实验表明,该算法优于主成分分析(PCA)、线性鉴别分析(LDA)、局部保留投影(LPP)和边界Fisher分析(MFA)。     

一种新颖混合贝叶斯分类模型研究

朴素贝叶斯分类器（Naive Bayesian classifier,NB）是一种简单而有效的分类模型,但这种分类器缺乏对训练集信息的充分利用,影响了它的分类性能。通过分析NB的分类原理,并结合线性判别分析（Linear Discriminant Analysis,LDA）与核判别分析（Kernel Discriminant Analysis,KDA）的优点,提出了一种混合贝叶斯分类模型DANB（Discriminant Analysis Naive Bayesian classifier,DANB）。将该分类方法与NB和TAN（Tree Augmented Naive Bayesian classifier,TAN）进行实验比较,结果表明,在大多数数据集上,DANB分类器具有较高的分类正确率。     

An improved discriminative common vectors and support vector machine based face recognition approach

An improved discriminative common vectors and support vector machine based face recognition approach is proposed in this paper. The discriminative common vectors (DCV) algorithm is a recently addressed discriminant method, which shows better face recognition effects than some commonly used linear discriminant algorithms. The DCV is based on a variation of Fisher’s Linear Discriminant Analysis for the small sample size case. However, for multiclass problem, the Fisher criterion is clearly suboptimal. We design an improved discriminative common vector by adjustment for the Fisher criterion that can estimate the within-class and between-class scatter matrices more accurately for classification purposes. Then we employ support vector machine as the classifier due to its higher classification and higher generalization. Testing on two public large face database: ORL and AR database, the experimental results demonstrate that the proposed method is an effective face recognition approach, which outperforms several representative recognition methods.     

Kernel-based nonlinear discriminant analysis for face recognition

Linear subspace analysis methods have been successfully applied to extract features for face recognition.But they are inadequate to represent the complex and nonlinear variations of real face images,such as illumination,facial expression and pose variations,because of their linear properties.In this paper,a nonlinear subspace analysis method,Kernel-based Nonlinear Discriminant Analysis (KNDA),is presented for face recognition,which combines the nonlinear kernel trick with the linear subspace analysis method-Fisher Linear Discriminant Analysis (FLDA).First,the kernel trick is used to project the input data into an implicit feature space,then FLDA is performed in this feature space.Thus nonlinear discriminant features of the input data are yielded.In addition,in order to reduce the computational complexity,a geometry-based feature vectors selection scheme is adopted.Another similar nonlinear subspace analysis is Kernel-based Principal Component Analysis (KPCA),which combines the kernel trick with linear Principal Component Analysis (PCA).Experiments are performed with the polynomial kernel,and KNDA is compared with KPCA and FLDA.Extensive experimental results show that KNDA can give a higher recognition rate than KPCA and FLDA.     

Face recognition by sparse discriminant analysis via joint L2,1-norm minimization

Recently, joint feature selection and subspace learning, which can perform feature selection and subspace learning simultaneously, is proposed and has encouraging ability on face recognition. In the literature, a framework of utilizing L_2,1-norm penalty term has also been presented, but some important algorithms cannot be covered, such as Fisher Linear Discriminant Analysis and Sparse Discriminant Analysis. Therefore, in this paper, we add L_2,1-norm penalty term on FLDA and propose a feasible solution by transforming its nonlinear model into linear regression type. In addition, we modify the optimization model of SDA by replacing elastic net with L_2,1-norm penalty term and present its optimization method. Experiments on three standard face databases illustrate FLDA and SDA via L_2,1-norm penalty term can significantly improve their recognition performance, and obtain inspiring results with low computation cost and for low-dimension feature.     

LDA算法及其在人脸识别中的应用

线性特征提取在人脸识别中的应用非常广泛,LDA是其主要方法之一,它基于Fisher 判别准则,然而,当人脸训练样本数小于人脸样本向量的维数时,变换矩阵将无法直接得到,因此线性判别分析过程失效。采用了一种改进的基于Fisher 准则的LDA方法,针对小样本问题提出了一种有效地解决类内散布矩阵奇异的方法,而且用ORL人脸数据进行了实验验证。实验证明该方法在正确识别率方面表现突出。