Face recognition using difference vector plus KPCA

In this paper, a novel approach for face recognition based on the difference vector plus kernel PCA is proposed. Difference vector is the difference between the original image and the common vector which is obtained by the images processed by the Gram-Schmidt orthogonalization and represents the common invariant properties of the class. The optimal feature vectors are obtained by KPCA procedure for the difference vectors. Recognition result is derived from finding the minimum distance between the test difference feature vectors and the training difference feature vectors. To test and evaluate the proposed approach performance, a series of experiments are performed on four face databases: ORL, Yale, FERET and AR face databases and the experimental results show that the proposed method is encouraging.     

一种基于共同向量结合2DPCA的人脸识别方法

提出了一种基于共同向量结合2维主成分分析(2-dimen-sional principal component analysis, 2DPCA)的人脸识别方法. 共同向量由图像通过Gram-Schmidt正交变换而求得, 具有该类图像共同不变的性质. 原始图像与该类共同向量之间的差分向量通过2DPCA处理, 依据最小距离测试得到识别结果. 实验在ORL和Yale人脸数据库进行测试, 结果表明本文提出的方法有较好的识别性能.     

基于聚类算法和层次支持向量机的人脸识别方法

提出一种基于聚类算法和层次支持向量机的人脸识别方法。该方法在训练阶段把利用小波变换提取的图像特征先进行聚类,再利用聚类的结果来训练层挺支持向量机;识别阶段先利用层次支持向量机初步判断待识别图像最可能所属的人,最后利用免疫算法对待识别的人脸图像进行确认。实验表明,该算法效果较佳。     

Face recognition by applying wavelet subband representation and kernel associative memory

In this paper, we propose an efficient face recognition scheme which has two features: 1) representation of face images by two-dimensional (2D) wavelet subband coefficients and 2) recognition by a modular, personalised classification method based on kernel associative memory models. Compared to PCA projections and low resolution "thumb-nail" image representations, wavelet subband coefficients can efficiently capture substantial facial features while keeping computational complexity low. As there are usually very limited samples, we constructed an associative memory (AM) model for each person and proposed to improve the performance of AM models by kernel methods. Specifically, we first applied kernel transforms to each possible training pair of faces sample and then mapped the high-dimensional feature space back to input space. Our scheme using modular autoassociative memory for face recognition is inspired by the same motivation as using autoencoders for optical character recognition (OCR), for which the advantages has been proven. By associative memory, all the prototypical faces of one particular person are used to reconstruct themselves and the reconstruction error for a probe face image is used to decide if the probe face is from the corresponding person. We carried out extensive experiments on three standard face recognition datasets, the FERET data, the XM2VTS data, and the ORL data. Detailed comparisons with earlier published results are provided and our proposed scheme offers better recognition accuracy on all of the face datasets.     

基于奇异值特征和统计模型的人像识别算法

人像识别是模式识别领域中的一个前沿课题。目前多数研究者采用人脸的一维和二维几何特征来完成识别任务。人脸的几何特征抽取以及这些特性的有效性都面临着很多问题，至今人像识别的研究仍然处于较低的水平。作者证明了图象矩阵的奇异值特征矢量具备了代数上和几何上的不变性以及稳定性，提出用它作为识别人脸的代数特征。本文的人像识别算法是基于奇异值特征矢量建立Ｓａｍｍｏｎ最佳鉴别平面上的正态Ｂａｙｅｓ分类模型。在本文的     

Vector projection for face recognition

In this paper, a novel approach for face recognition is proposed by using vector projection length to formulate the pattern recognition problem. Face images of a single-object class are more similar than those of different-object classes. The projection length of a test image vector on the direction of a training image vector can measure the similarity of the two images. But the decision cannot be made by only a training image which is the most similar to the test one, the mean image vector of each class also contributes to the final classification. Thus, the decision of the proposed vector projection classification (VPC) algorithm is ruled in favor of the maximum combination projection length. To address the partial occlusion problem in face recognition, we propose a local vector projection classification (LVPC) algorithm. The experimental results show that the proposed VPC and LVPC approaches are efficient and outperform some existing approaches.     

基于神经网络和层次SVM的多姿态人脸识别

提出了一种基于神经网络和层次支持向量机的多姿态人脸识别方法。该方法在训练阶段先利用神经网络把姿态人脸图像特征向准标准人脸图像特征映射，再根据聚类结果来训练支持向量机。识别阶段是利用神经网络变换得到待识别图像所对应的准标准图像的特征，再让层次支持向量机初步判断待识别图像最可能所属的人，最后利用否定算法对待识别的人脸图像进行确认。实验表明该算法效果较佳。     

基于聚类算法和层次SVM的姿态人脸识别方法

提出了一种基于神经网络和层次支持向量机的多姿态人脸识别方法.该方法在训练阶段先利用神经网络把姿态人脸图像特征向准标准人脸图像特征映射,再根据聚类结果来训练支持向量机.识别阶段是先利用神经网络变换得到待识别图像所对应的准标准图像的特征,再让层次支持向量机初步判断待识别图像最可能所属的人,最后利用否定算法对待识别的人脸图像进行确认,实验表明该算法效果较佳.     

基于免疫算法和层次支持向量机的人脸识别方法

给出了一种基于免疫算法及层次支持向量机的人脸识别方法,该方法先利用Gabor小泼变换提取待识别的人脸图像的特征向量,然后利用层次支持向量机初步判断该图像最可能所属的人,最后利用免疫算法对待识别的人脸图像进行确认.实验表明,该算法效果较佳.     

基于小波和奇异值分解的人脸识别方法

该文提出了一种基于小波和奇异值分解的人脸识别方法。首先对人脸图象进行小波分解,由于小波变换具有良好的多尺度特征表达能力,能将图象的大部分能量集中到低频子图中,使图象得到有效压缩。然后,对得到的每幅低频子图进行基于奇异值分解的特征提取,并将奇异值特征向量进行压缩,把压缩后的特征向量作为每幅人脸图象的特征,进而求出每一类人脸图象的特征向量中心。最后,将每一类的特征向量中心输入到分类器中进行识别。最终得到了令人满意的识别结果。     

The kernel common vector method: a novel nonlinear subspace classifier for pattern recognition.

The common vector (CV) method is a linear subspace classifier method which allows one to discriminate between classes of data sets, such as those arising in image and word recognition. This method utilizes subspaces that represent classes during classification. Each subspace is modeled such that common features of all samples in the corresponding class are extracted. To accomplish this goal, the method eliminates features that are in the direction of the eigenvectors corresponding to the nonzero eigenvalues of the covariance matrix of each class. In this paper, we introduce a variation of the CV method, which will be referred to as the modified CV (MCV) method. Then, a novel approach is proposed to apply the MCV method in a nonlinearly mapped higher dimensional feature space. In this approach, all samples are mapped into a higher dimensional feature space using a kernel mapping function, and then, the MCV method is applied in the mapped space. Under certain conditions, each class gives rise to a unique CV, and the method guarantees a 100% recognition rate with respect to the training set data. Moreover, experiments with several test cases also show that the generalization performance of the proposed kernel method is comparable to the generalization performances of other linear subspace classifier methods as well as the kernel-based nonlinear subspace method. While both the MCV method and its kernel counterpart did not outperform the support vector machine (SVM) classifier in most of the reported experiments, the application of our proposed methods is simpler than that of the multiclass SVM classifier. In addition, it is not necessary to adjust any parameters in our approach.     

Image preprocessing method based on local approximation gradient with application to face recognition

In order to obtain more robust face recognition results, the paper proposes an image preprocessing method based on local approximation gradient (LAG). The traditional gradient is only calculated along 0° and 90°; however, there exist many other directional gradients in an image block. To consider more directional gradients, we introduce a novel LAG operator. The LAG operator is actually calculated by integrating more directional gradients. Because of considering more directional gradients, LAG captures more edge information for each pixel of an image and finally generates an LAG image, which achieves a more robust image dissimilarity between images. An LAG image is normalized into an augmented feature vector using the “z-score” method. The dimensionality of the augmented feature vector is reduced by linear discriminant analysis to yield a low-dimensional feature vector. Experimental results show that the proposed method achieves more robust results in comparison with state-of-the-art methods in AR, Extended Yale B and CMU PIE face database.     

Orthogonal discriminant vector for face recognition across pose

Recognizing face images across pose is one of the challenging tasks for reliable face recognition. This paper presents a new method to tackle this challenge based on orthogonal discriminant vector (ODV). The result of our theoretical analysis shows that an individual’s probe image captured with a new pose can be represented by a linear combination of his/her gallery images. Based on this observation, in contrast to the conventional methods which model face images of different individuals on a single manifold, we propose to model face images of different individuals on different linear manifolds. The contribution of our approach includes: (1) to prove that the orthogonality to ODVs is a pose-invariant feature.; (2) to categorize each person with a set of ODVs, where his/her face images posses zero projections while other persons’ images are characterized by maximum projections; (3) to define a metric to measure the distance between a face image and an ODV, and classify the face images based on this metric. Our experimental results validate the feasibility of modeling the face images of different individuals on different linear manifolds. The proposed method achieves higher accuracy on face recognition and verification than the existing techniques.     

基于分类稀疏表示的人脸表情识别

为挖掘不同人脸表情图像的统计特性差异,提出一种基于分类稀疏表示的表情识别算法。首先通过对不同类别表情图像的字典学习,构建满足各类表情图像统计特性的基函数子集,进而采用Lasso算法获得表情图像在由基函数集所张成特征子空间中的稀疏表示,最后通过比较表情图像在各基函数子集上的重构误差实现不同表情的分类识别。基于JAFFE人脸表情数据库的实验结果表明,该算法可以有效克服人脸身份对表情识别的影响,具有较高的表情识别率和鲁棒性。     

基于奇异值特征提取的彩色人脸识别*

基于彩色图像的四元数模型,将彩色人脸图像视为一个模板直接处理,并首次将奇异值向量应用到彩色人脸识别中.首先证明了彩色图像的奇异值向量具有代数和几何不变性;然后将其提取为图像的代数特征并应用到人脸识别中.实验表明该方法的识别率为90%左右,是一种有效的彩色人脸识别方法.     

基于BP神经网络的人脸识别方法

人脸自动识别是计算机模式识别领域的一个活跃课题,有着十分广泛的应用前景。文中提出了基于ＢＰ神经网络的人脸识别方法,论述了人脸图像矢量的特征压缩问题、网络隐含层神经元数选取问题、网络输入矢量的标准化处理问题以及网络连接权值选取问题。对于１８人、每人１２幅图像组成的脸图像数据库做识别实验,实验结果表明文中所设计的神经网络分类器比常用的最近邻分类器有效地降低了识别错误率。     

3D通用人脸模型的自适应算法及应用

利用3D人脸建模的方法进行人脸识别有效地克服了2D人脸识别系统中识别率易受光照、姿态、表情影响的缺陷。文章采用一种依据人脸图像对3D通用人脸模型进行自适应调整的有效算法,构造出特定的人脸模型并运用于人脸识别中。通过比较从人脸图像中估算出的特征点与通用人脸模型在图像平面上的投影点之间的关系,对3D通用人脸模型进行全局和局部调整,以适应人脸中眼、口、鼻的个性化特征。最后以一个实例说明了此算法的应用。     

基于复合梯度向量的人脸识别算法

提出了一种新的基于复合梯度向量(Composite gradient vector, CGV)描述的人脸识别算法. 该算法首先在定位后的人脸图像中标定目标区域, 并在目标区域内划分特征子区域, 然后,以特征子区域的边缘奇异点作为向量的起点和终点进行正交采样得到基向量, 将目标区域内所有基向量组建向量簇, 通过对基向量的多维复合得到向量簇内所有极大梯度向量, 最后,以极大梯度向量作为元素组建复合梯度向量并统计复合梯度向量的维度和梯度信息, 将复合梯度向量、复合梯度向量维度和梯度进行人脸库对比, 识别出人脸身份. 该算法抓住了人脸面部特征分散性的特点, 继而对分散性特征采用具有连续性规律约束的复合梯度向量进行描述识别. 实验结果表明, 该算法克服了特征域旋转、光照强度变化及多姿态、多表情对人脸识别的影响, 具有速度快、识别准确、适应性强的特点.     

Pose Robust Low-resolution Face Recognition via Coupled Kernel-based Enhanced Discriminant Analysis

Most face recognition techniques have been successful in dealing with high-resolution (HR) frontal face images. However, real-world face recognition systems are often confronted with the low-resolution (LR) face images with pose and illumination variations. This is a very challenging issue, especially under the constraint of using only a single gallery image per person. To address the problem, we propose a novel approach called coupled kernel-based enhanced discriminant analysis (CKEDA). CKEDA aims to simultaneously project the features from LR non-frontal probe images and HR frontal gallery ones into a common space where discrimination property is maximized. There are four advantages of the proposed approach: 1) by using the appropriate kernel function, the data becomes linearly separable, which is beneficial for recognition; 2) inspired by linear discriminant analysis (LDA), we integrate multiple discriminant factors into our objective function to enhance the discrimination property; 3) we use the gallery extended trick to improve the recognition performance for a single gallery image per person problem; 4) our approach can address the problem of matching LR non-frontal probe images with HR frontal gallery images, which is difficult for most existing face recognition techniques. Experimental evaluation on the multi-PIE dataset signifies highly competitive performance of our algorithm.      

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.