基于轮廓波变换和核Fisher判别分析的人脸识别

Contourlet变换是一种新的多尺度几何分析方法,它不仅具有小波变换的多分辨率特性和时频局域特性,还具有很强的方向性和各向异性.提出基于Contourlet变换和核Fisher判别分析的人脸识别方法,研究了Contourlet变换的低频系数、各层高频系数与核Fisher判别分析相结合进行人脸识别的识别率和识别时间.实验表明,Contourlet变换的低频系数与核Fisher判别分析相结合,有优异的识别率,也减少了识别时间;高频成分有一定的识别性能,但识别率较低.将低频成分与高频方向子带相结合能获得最优的识别率.     

基于改进傅里叶描绘子的CBIR系统

在现有的基于傅里叶描绘子的CBIR系统中,为了提高检索速度,一般需要舍去物体轮廓经傅里叶变换后的大部分高频分量.当物体轮廓在细节部分具有较高能量时,此方法不具备有效性.为尽可能保证检索准确率并兼顾检索速度,在原有傅里叶描绘子上进行扩展,避免直接舍去高频分量,引入Fisher判别分析法将描绘子映射到子空间进行降维,并保证...     

子空间半监督Fisher判别分析

Fisher判别分析寻找一个使样本数据类间散度与样本数据类内散度比值最大的子空间, 是一种很流行的监督式特征降维方法. 标注样本数据所属的类别通常需要大量的人工, 消耗大量的时间, 付出昂贵的成本. 为了解决同时利用有类别信息的样本数据和没有类别信息的样本数据用于寻找降维子空间的问题, 我们提出了一种子空间半监督Fisher判别分析方法. 子空间半监督Fisher判别分析寻找这样一个子空间, 这个子空间即保留了从有类别信息的样本数据中学习的类别判别结构, 也保留了从有类别信息的样本数据和没有类别信息的样本数据中学习的样本结构信息. 我们还推导了基于核的子空间半监督Fisher判别分析方法. 通过人脸识别实验验证了本文算法的有效性.     

Induction of multiclass multifeature split decision trees from distributed data

The decision tree-based classification is a popular approach for pattern recognition and data mining. Most decision tree induction methods assume training data being present at one central location. Given the growth in distributed databases at geographically dispersed locations, the methods for decision tree induction in distributed settings are gaining importance. This paper describes one such method that generates compact trees using multifeature splits in place of single feature split decision trees generated by most existing methods for distributed data. Our method is based on Fisher's linear discriminant function, and is capable of dealing with multiple classes in the data. For homogeneously distributed data, the decision trees produced by our method are identical to decision trees generated using Fisher's linear discriminant function with centrally stored data. For heterogeneously distributed data, a certain approximation is involved with a small change in performance with respect to the tree generated with centrally stored data. Experimental results for several well-known datasets are presented and compared with decision trees generated using Fisher's linear discriminant function with centrally stored data.     

Complete discriminant evaluation and feature extraction in kernel space for face recognition

This work proposes a method to decompose the kernel within-class eigenspace into two subspaces: a reliable subspace spanned mainly by the facial variation and an unreliable subspace due to limited number of training samples. A weighting function is proposed to circumvent undue scaling of eigenvectors corresponding to the unreliable small and zero eigenvalues. Eigenfeatures are then extracted by the discriminant evaluation in the whole kernel space. These efforts facilitate a discriminative and stable low-dimensional feature representation of the face image. Experimental results on FERET, ORL and GT databases show that our approach consistently outperforms other kernel based face recognition methods.

一种改进的步态识别方法

步态识别通过人体走路的姿势来识别人的身份。近年来,步态作为一种生物特征识别技术备受计算机视觉研究者的关注。对某个人的一个步态序列利用动态Viterbi算法得到一个样本姿态序列,对其多个步态样本姿态序列的对应姿态取平均得到这个人的特征姿态序列,对特征姿态采用主成分分析法和线性判别分析法处理特征空间,并用最近邻法进行识别。利用CASIA数据库对本文方法进行验证,取得了较高的识别率,并对体形变化具有较强的鲁棒性。     

Fault diagnosis of nonlinear and large-scale processes using novel modified kernel Fisher discriminant analysis approach

It is pretty significant for fault diagnosis timely and accurately to improve the dependability of industrial processes. In this study, fault diagnosis of nonlinear and large-scale processes by variable-weighted kernel Fisher discriminant analysis (KFDA) based on improved biogeography-based optimisation (IBBO) is proposed, referred to as IBBO-KFDA, where IBBO is used to determine the parameters of variable-weighted KFDA, and variable-weighted KFDA is used to solve the multi-classification overlapping problem. The main contributions of this work are four-fold to further improve the performance of KFDA for fault diagnosis. First, a nonlinear fault diagnosis approach with variable-weighted KFDA is developed for maximising separation between the overlapping fault samples. Second, kernel parameters and features selection of variable-weighted KFDA are simultaneously optimised using IBBO. Finally, a single fitness function that combines erroneous diagnosis rate with feature cost is created, a novel mixed kernel function is introduced to improve the classification capability in the feature space and diagnosis accuracy of the IBBO-KFDA, and serves as the target function in the optimisation problem. Moreover, an IBBO approach is developed to obtain the better quality of solution and faster convergence speed. On the one hand, the proposed IBBO-KFDA method is first used on Tennessee Eastman process benchmark data sets to validate the feasibility and efficiency. On the other hand, IBBO-KFDA is applied to diagnose faults of automation gauge control system. Simulation results demonstrate that IBBO-KFDA can obtain better kernel parameters and feature vectors with a lower computing cost, higher diagnosis accuracy and a better real-time capacity.     

基于零空间分析的张量局部Fisher判别方法

结合局部Fisher判别、张量子空间学习和零空间分析等技术的优点,提出了一种基于零空间分析的张量局部Fisher判别算法,其特点包括:i) 引入类间判别信息,对局部Fisher判别技术进行调整,提升了算法识别性能并且降低了计算时间复杂度;ii) 通过张量型降维思想对输入样本进行双边投影变换而非单边投影,获得了更高的信息压缩率;iii) 随着训练样本量的变化,可采用基于零空间分析的求解方法和传统的直接迭代更新计算方法。通过ORL、Yale和ExYaleB 3个人脸数据库验证了所提算法的性能。     

Face recognition based on 2D images under illumination and pose variations

We propose a novel 2D image-based approach that can simultaneously handle illumination and pose variations to enhance face recognition rate. It is much simpler, requires much less computational effort than the methods based on 3D models, and provides a comparable or better recognition rate.     

基于最佳鉴别变换和分类器组合的人脸自动识别

人脸识别技术在商业和法律上有广泛的应用前景 ,在安全监控中也大有用武之地 .其主要任务是利用已有的人脸图象库 ,识别静止的或视频图象中的一张或多张人脸 .从抽取具有统计不相关的模式特征着手 ,通过基于小波变换的图象分解和 KL 变换等处理 ,避开人脸识别的小样本集的局限 ,并通过运用具有统计不相关性的最佳鉴别变换 ,来抽取人脸的有效鉴别特征 .同时 ,利用多特征多分类器组合的方法对图象进行识别 .该方法在 ORL 人脸图象库上进行实验 ,得到识别错误率为 2 %的实验结果 ,这是目前在此人脸图象数据库上所得到的最好的实验结果 .而且本方法对人脸的姿态、表情等条件具有一定的不敏感性