基于个人特征脸图像重构的人脸识别

传统的基于PCA(Principal component analysis)的人脸识别方法产生的人脸特征子空间通常是由人脸库中的所有训练样本产生的,此子空间包含的更多的是所有人脸样本的共性特征,而忽略了人脸的一些个性特征.本文提出了一种基于PCA图像重构的人脸识别方法,该方法以单个人的类内协方差矩阵为特征脸产生矩阵,获取个人的人脸特征子空间,然后将待识别图像对每个特征子空间进行映射提取人脸图像主成分,并以此主成分进行图像重构,采用最小重构误差作为判据实现人脸的识别,最后基于ORL及Yale人脸数据库,实验验证了该方法的有效性.     

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。     

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.     

基于BP神经网络的主分量分析人脸识别算法

提出了基于BP神经网络的主分量人脸识别算法。该算法首先用小波变换对人脸图像进行小波分解,形成低频小波子图,然后用主分量分析法构造特征脸子空间,将人脸图像在特征空间的投影作为BP神经网络的输入,由BP神经网络和后验概率转换器构成人脸识别器。针对ORL人脸库的实验结果表明该方法具有较高的识别率。     

基于子模式的Gabor特征融合的单样本人脸识别

针对传统人脸识别方法在单训练样本条件下效果不佳的缺点,提出基于子模式的Gabor特征融合方法并用于单样本人脸识别。首先采用Gabor变换抽取人脸局部信息,为有效利用面部器官的空间位置信息,将Gabor人脸图像分块构成子模式,采用最小距离分类器对各子模式分类。最后对各子模式分类结果做决策级融合得出分类结果。根据子模式构成原则和决策级融合策略不同,提出两种子模式Gabor特征融合方法。利用ORL人脸库和CAS-PEAL-R1人脸库进行实验和比较分析,实验结果表明文中方法有效提高单样本人脸识别的正确率,改善单样本人脸识别系统的性能。     

基于加权对称图像的二维FDA人脸识别算法

提出一种融合加权对称图像的二维FDA人脸识别算法。将人脸图像分解为奇偶对称脸,并利用加权因子将奇偶对称脸重构新的人脸样本,通过二维FDA算法求解新样本图像的最优特征子空间进行人脸分类。有效融合二维FDA算法的优点,并利用人脸对称性的特征,同时进一步分析加权因子对人脸识别效果的影响,通过选取最优加权因子最大地提高识别率。在人脸图像库ORL中进行的实验结果表明,该算法有效并能获得较高的识别率。     

相关滤波器和2DPCA相融合的变光照人脸识别

为解决变光照下人脸识别的识别率低问题,提出一种最佳相关滤波和2DPCA相融合的光照人脸识别方法。通过采用特定类2DPCA重构人脸图像,生成一对相关滤波器;测试人脸图像通过相关性滤器将投影到二维子空间中,并根据预先设定的峰旁瓣比阈值进行人脸识别;最后采用PIE和YaleB人脸库进行仿真实验。相比其他人脸识别方法,该方法获得了更高的人脸识别率,鲁棒性更强。     

基于粒子群BP神经网络人脸识别算法

人脸识别技术就是利用计算机技术对人脸图像进行分析,从中提取有效的特征来识别出人的身份,其关键技术在于人脸特征的描述和模式识别.为此,基于粒子群BP神经网络提出了人脸识别算法.该算法首先用小波变换对人脸图像进行小波分解,形成低频小波子图,然后用离散余弦变换将人脸图像在特征空间中提取,并作为粒子群BP神经网络的输入,由粒子群BP神经网络和后验概率转换器构成人脸识别器.针对ORL人脸库的实验结果表明该方法具有较高的识别率.     

FLDA在单样本人脸识别中的应用研究

随着人脸识别技术的不断发展,单样本人脸识别已成为当今的一个热点。针对单样本人脸识别问题,提出一种基于通用框架学习的人脸识别方法。以大量的通用样本与各个单样本按一定比例叠加的方式,增加每个类的训练样本总数,有效地运用FLDA方法进行特征抽取,将所有样本投影到特征子空间,再利用最近邻方法完成人脸识别,一定程度上减轻了人脸的表情、姿态、光照等因素对识别效果的影响,提高了识别率。该方法的有效性分别在ORL及Yale两大人脸库上得到了验证。     

基于水平镜像和决策融合的多姿态人脸识别方法

多姿态人脸识别是模式识别领域的难题之一。首先采用水平镜像方法增加训练样本,并将所有训练样本在[-90,+90]的姿态范围内划分为7个子集,利用Gabor和2DPCA方法生成7个特征子空间。识别时,提取输入图像及其水平镜像图像的特征并分别向7个特征子空间投影,根据投影距离,采用决策融合判决策略得到最终的识别结果。在三个人脸库上的实验证明,在仅选取有限的多姿态训练样本的情况下,对旋转角度介于[-90,+90]的多姿态人脸能取得较高的识别率。     

任意光照下人脸图像的低维光照空间表示

本文提出一种不同光照条件下人脸图像的低维光照空间表示方法.这种低维光照空间表示不仅能够由输入图像估计其光照参数，而且能够由给定的光照条件生成虚拟的人脸图像.利用主成分分析和最近邻聚类方法得到9个基本点光源的位置，这9个基本点光源可以近似人脸识别应用中几乎所有的光照条件.在这9个基本光源照射下的9幅人脸基图像构成了低维人脸光照空间，它可以表示不同光照条件下的人脸图像，结合光照比图像方法，可以生成不同光照下的虚拟人脸图像.本文提出的低维光照空间的最大优点是利用某个人脸的图像建立的光照空间，可以用于不同的人脸.图像重构和不同光照下的人脸识别实验说明了本文算法的有效性.     

OptiFuzz: a robust illumination invariant face recognition system and its implementation

Vision-based human face detection and recognition are widely used and have been shown to be effective in normal illumination conditions. Under severe illumination conditions, however, it is very challenging. In this paper, we address the effect of illumination on the face detection and the face recognition problem by introducing a novel illumination invariant method, called OptiFuzz. It is an optimized fuzzy-based illumination invariant method to solve the effect of illumination for photometric-based human face recognition. The rule of the Fuzzy Inference System is optimized by using a genetic algorithm. The Fuzzy’s output controls an illumination invariant model that is extended from Land’s reflectance model. We test our method by using Yale B Extended and CAS-PEAL face databases to represent the offline experiments, and several videos are recorded at our campus to represent the online indoor and outdoor experiments. Viola–Jones face detector and mutual subspace method are employed to handle the online face detection and face recognition experiments. Based on the experimental results, we can show that our algorithm outperforms the existing and the state-of-the-art methods in recognizing a specific person under variable lighting conditions with a significantly improved computation time. Other than that, using illumination invariant images is also effective in improving the face detection performance.     

High-speed face recognition using self-adaptive radial basis function neural networks

In this work, we have proposed a self-adaptive radial basis function neural network (RBFNN)-based method for high-speed recognition of human faces. It has been seen that the variations between the images of a person, under varying pose, facial expressions, illumination, etc., are quite high. Therefore, in face recognition problem to achieve high recognition rate, it is necessary to consider the structural information lying within these images in the classification process. In the present study, it has been realized by modeling each of the training images as a hidden layer neuron in the proposed RBFNN. Now, to classify a facial image, a confidence measure has been imposed on the outputs of the hidden layer neurons to reduce the influences of the images belonging to other classes. This process makes the RBFNN as self-adaptive for choosing a subset of the hidden layer neurons, which are in close neighborhood of the input image, to be considered for classifying the input image. The process reduces the computation time at the output layer of the RBFNN by neglecting the ineffective radial basis functions and makes the proposed method to recognize face images in high speed and also in interframe period of video. The performance of the proposed method has been evaluated on the basis of sensitivity and specificity on two popular face recognition databases, the ORL and the UMIST face databases. On the ORL database, the best average sensitivity (recognition) and specificity rates are found to be 97.30 and 99.94%, respectively using five samples per person in the training set. Whereas, on the UMIST database, the above quantities are found to be 96.36 and 99.81%, respectively using eight samples per person in the training set. The experimental results indicate that the proposed method outperforms some of the face recognition approaches.     

On the false rejection ratio of face recognition based on automatic detected feature points

The authors propose a new face recognition system with an evaluation function using feature points. The feature points are detected automatically by Milborrow’s Stasm software. Before recognition, rotation compensation and size normalization are applied to the feature points. The main method is to calculate the squared error between the registered face and the input face as to length of a characteristic pair of feature points on face. The False Rejection Rate (FRR) for the registered and input face of the same person, and the False Acceptance Rate (FAR) for the registered face and a different person’s input face are evaluated. The input is a video sequence. Stable recognition is obtained with small FRR and FAR for the video of a period of 0.5 s.     

基于Trace变换的人脸特征提取技术研究*

为了提高人脸特征的稳定性和区分度,提出了一种基于Trace变换的人脸特征提取算法。算法通过几种不同的泛函函数对预处理后的人脸图像进行组合作用,得到该图像的一个Trace特征向量,从而建立了一种新的人脸特征表达方式。基于ORL人脸数据库的实验结果表明,该算法所提出的人脸特征对同一个人不同表情、不同光照条件下的图像变化能够保持较好的稳定性,同时对不同人的人脸图像具有较高的区分能力,在人脸识别的实际应用中是一种可行的方法。     

基于位平面图像与2DMSLDA的单样本人脸识别

在进行单训练样本人脸识别时,基于每人多个训练样本的传统人脸识别算法效果通常不太理想。尤其是基于Fisher线性鉴别准则的一些方法,由于类内散布矩阵为零矩阵,根本无法进行识别。针对以上问题进行了分析研究,提出了一种新的样本扩充方法,即：采用位平面图像分解法,将每幅样本图像分解为8幅,进而通过各种合成策略构造多幅样本图像。使用一种更加稳定的二维最大散度差线性鉴别分析方法（2DMSLDA）对上面获得的新样本图像进行特征抽取。在ORL国际标准人脸库上进行的实验表明了所提算法的可行性和有效性。     

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.     

Open-set face recognition across look-alike faces in real-world scenarios

The open-set problem is among the problems that have significantly changed the performance of face recognition algorithms in real-world scenarios. Open-set operates under the supposition that not all the probes have a pair in the gallery. Most face recognition systems in real-world scenarios focus on handling pose, expression and illumination problems on face recognition. In addition to these challenges, when the number of subjects is increased for face recognition, these problems are intensified by look-alike faces for which there are two subjects with lower intra-class variations. In such challenges, the inter-class similarity is higher than the intra-class variation for these two subjects. In fact, these look-alike faces can be created as intrinsic, situation-based and also by facial plastic surgery. This work introduces three real-world open-set face recognition methods across facial plastic surgery changes and a look-alike face by 3D face reconstruction and sparse representation. Since some real-world databases for face recognition do not have multiple images per person in the gallery, with just one image per subject in the gallery, this paper proposes a novel idea to overcome this challenge by 3D modeling from gallery images and synthesizing them for generating several images. Accordingly, a 3D model is initially reconstructed from frontal face images in a real-world gallery. Then, each 3D reconstructed face in the gallery is synthesized to several possible views and a sparse dictionary is generated based on the synthesized face image for each person. Also, a likeness dictionary is defined and its optimization problem is solved by the proposed method. Finally, the face recognition is performed for open-set face recognition using three proposed representation classifications. Promising results are achieved for face recognition across plastic surgery and look-alike faces on three databases including the plastic surgery face, look-alike face and LFW databases compared to several state-of-the-art methods. Also, several real-world and open-set scenarios are performed to evaluate the proposed method on these databases in real-world scenarios.     

基于泛滑动窗与加权2DLDA的单样本人脸识别

对于单训练样本人脸识别,基于每人多个训练样本的传统人脸识别算法效果均不太理想。尤其是基于Fisher线性鉴别准则的一些方法,由于类内散布矩阵为零矩阵,根本无法进行识别。针对这一问题进行了分析研究,提出了一种新的样本扩充方法,即泛滑动窗法。采用“大窗口,小步长”的机制进行窗口图像采集和样本扩充,不仅增加了训练样本,而且充分保持和强化了原始样本模式固有的类内和类间信息。然后,使用加权二维线性鉴别分析方法（Weighted 2DLDA）对上面获得的窗口图像进行特征抽取。在ORL国际标准人脸库上进行的实验表明了所提算法的可行性和有效性。     

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.