A novel sparse representation method based on virtual samples for face recognition

Though sparse representation (Wagner et al. in IEEE Trans Pattern Anal Mach Intell 34(2):372–386, 2012, CVPR 597–604, 2009) can perform very well in face recognition (FR), it still can be improved. To improve the performance of FR, a novel sparse representation method based on virtual samples is proposed in this paper. The proposed method first extends the training samples to form a new training set by adding random noise to them and then performs FR. As the testing samples can be represented better with the new training set, the ultimate classification obtained using the proposed method is more accurate than the classification based on the original training samples. A number of FR experiments show that the classification accuracy obtained using our method is usually 2–5 % greater than that obtained using the method mentioned in Xu and Zhu (Neural Comput Appl, 2012).     

A novel illumination-robust face recognition using statistical and non-statistical method

This paper proposes a novel illumination-robust face recognition technique that combines the statistical global illumination transformation and the non-statistical local face representation methods. When a new face image with arbitrary illumination is given, it is transformed into a number of face images exhibiting different illuminations using a statistical bilinear model-based indirect illumination transformation. Each illumination transformed image is then represented by a histogram sequence that concatenates the histograms of the non-statistical multi-resolution uniform local Gabor binary patterns (MULGBP) for all the local regions. This is facilitated by dividing the input image into several regular local regions, converting each local region using several Gabor filters, and converting each Gabor filtered region image into multi-resolution local binary patterns (MULBP). Finally, face recognition is performed by a simple histogram matching process. Experimental results demonstrate that the proposed face recognition method is highly robust to illumination variation as exhibited in the real environment.     

A novel face recognition method based on sub-pattern and tensor

This paper aims to address one of the many problems existing in current facial recognition techniques using tensor (TensorFace Algorithm and its extensions). Current methods rasterize facial images as vectors, which result in a loss of spatial structure information of facial images. In this paper, we propose a method called Sp-Tensor to extend TensorFace by applying the sub-pattern technique. Advantages of the proposed method include: (1) a portion of spatial structure and local information of facial images is preserved; (2) dramatically reduce the computation complexity than other existing methods when building the model. The experimental results demonstrate that Sp-Tensor has better performance than the original TensorFace and Sp-PCA1, especially for facial images with un-modeled views and light conditions.     

A Kernel-based sparse representation method for face recognition

Sparse Representation Method has been proved to outperform conventional face recognition (FR) methods and is widely applied in recent years. A novel Kernel-based Sparse Representation Method (KBSRM) is proposed in this paper. In order to cope with the possible complex variation of the face images caused by varying facial expression and pose, the KBSRM first uses a kernel-induced distance to determine N nearest neighbors of the testing sample from all the training samples. Then, in the second step, the KBSRM represents the testing sample as a linear combination of the determinate N nearest neighbors and performs the classification by the representation result. It can be inferred that the N nearest training samples selected are closer to the test sample than the rest, so using the N nearest neighbors to represent the testing sample can make the ultimate classification more accurate. A number of FR experiments show that the KBSRM can achieve a better classification result than the algorithm mentioned in Xu et al. (Neural Comput Appl doi:10.1007/s00521-012-0833-5).     

marginFace: A novel face recognition method by average neighborhood margin maximization

We propose a novel appearance-based face recognition method called the marginFace approach. By using average neighborhood margin maximization (ANMM), the face images are mapped into a face subspace for analysis. Different from principal component analysis (PCA) and linear discriminant analysis (LDA) which effectively see only the global Euclidean structure of face space, ANMM aims at discriminating face images of different people based on local information. More concretely, for each face image, it pulls the neighboring images of the same person towards it as near as possible, while simultaneously pushing the neighboring images of different people away from it as far as possible. Moreover, we propose an automatic approach for determining the optimal dimensionality of the embedded subspace. The kernelized (nonlinear) and tensorized (multilinear) form of ANMM are also derived in this paper. Finally the experimental results of applying marginFace to face recognition are presented to show the effectiveness of our method.     

A novel maximum margin neighborhood preserving embedding for face recognition

This paper presents a novel supervised linear dimensionality reduction approach called maximum margin neighborhood preserving embedding (MMNPE). The central idea is to modify the neighborhood preserving embedding by maximizing the maximum margin distance while preserving the geometric structure of the manifold. Experimental results conducted on the ORL database, the Yale database and the VALID face database indicate the effectiveness of the proposed MMNPE.     

Two-dimensional Laplacianfaces method for face recognition

In this paper we propose a two-dimensional (2D) Laplacianfaces method for face recognition. The new algorithm is developed based on two techniques, i.e., locality preserved embedding and image based projection. The 2D Laplacianfaces method is not only computationally more efficient but also more accurate than the one-dimensional (1D) Laplacianfaces method in extracting the facial features for human face authentication. Extensive experiments are performed to test and evaluate the new algorithm using the FERET and the AR face databases. The experimental results indicate that the 2D Laplacianfaces method significantly outperforms the existing 2D Eigenfaces, the 2D Fisherfaces and the 1D Laplacianfaces methods under various experimental conditions.     

Median MSD-based method for face recognition

An improved maximum scatter difference (MSD) criterion is proposed in this paper. A weakness of existing MSD model is that the class mean vector in the expressions of within-class scatter matrix and between-class scatter matrix is estimated by class sample average. Under the non-ideal conditions such as variations of expression, illumination, pose, and so on, there will be some outliers in the sample set, so the class sample average is not sufficient to provide an accurate estimate of the class mean using a few of given samples. As a result, the recognition performance of traditional MSD model will decrease. To address this problem, also to render MSD model rather robust, within-class median vector rather than within-class mean vector is used in the original MSD method. The results of experiments conducted on CAS-PEAL and FERET face database indicate the effectiveness of the proposed approach.     

A novel method for automatic modulation recognition

Automatic recognition of the digital modulation plays an important role in various applications. This paper investigates the design of an accurate system for recognition of digital modulations. First, it is introduced an efficient pattern recognition system that includes two main modules: the feature extraction module and the classifier module. Feature extraction module extracts a suitable combination of the higher order moments up to eighth, higher order cumulants up to eighth and instantaneous characteristics of digital modulations. These combinations of the features are applied for the first time in this area. In the classifier module, two important classes of supervised classifiers, i.e., multi-layer perceptron (MLP) neural network and hierarchical multi-class support vector machine based classifier are investigated. By experimental study, we choose the best classifier for recognition of the considered modulations. Then, we propose a hybrid heuristic recognition system that an optimization module is added to improve the generalization performance of the classifier. In this module we have used a new optimization algorithm called Bees Algorithm. This module optimizes the classifier design by searching for the best value of the parameters that tune its discriminant function, and upstream by looking for the best subset of features that feed the classifier. Simulation results show that the proposed hybrid intelligent technique has very high recognition accuracy even at low levels of SNR with a little number of the features.     

一种基于卷积神经网络的人脸识别方法

近年来,随着深度学习的发展,卷积神经网络已经广泛运用到图像识别领域,它不仅提高了识别的准确率,同时自特征提取方面的效果也优于许多传统的算法。提出一种基于卷积神经网络的人脸识别算法。该方法主要涉及两方面,一是使用卷积神经网络对训练集进行特征提取;二是将提取的特征图片输入改进的神经网络进行训练及识别。通过MATLAB进行了仿真实验,对比结果表明卷积神经网络有很好的特征提取性能及良好识别效果,比现有的算法有很大的优势。     

A novel face recognition algorithm for distinguishing faces with various angles

In order to distinguish faces of various angles during face recognition, an algorithm of the combination of approximate dynamic programming （ADP） called action dependent heuristic dynamic programming （ADHDP） and particle swarm optimization （PSO） is presented. ADP is used for dynamically changing the values of the PSO parameters. During the process of face recognition, the discrete cosine transformation （DCT） is first introduced to reduce negative effects. Then, Karhunen-Loeve （K-L） transformation can be used to compress images and decrease data dimensions. According to principal component analysis （PCA）, the main parts of vectors are extracted for data representation. Finally, radial basis function （RBF） neural network is trained to recognize various faces. The training of RBF neural network is exploited by ADP-PSO. In terms of ORL Face Database, the experimental result gives a clear view of its accurate efficiency.     

A novel lossless recovery algorithm for basic matrix-based VSS

Lossless recovery is very important for visual secret share (VSS). In this paper, a novel lossless recovery algorithm for the basic matrix-based VSS is proposed. The algorithm has the merit of reconstructing secret image losslessly by using simple addition operation. The algorithm proves that the condition of lossless recovery of the secret image is ξ0 ∩ ξ1 = ? by analyzing the Hamming weight of adding all columns of basic matrixes. Simulations are conducted to evaluate the efficiency of the proposed scheme.

     

增强的无监督人脸鉴别技术

增强的独立分量分析（EICA）是一种基于样本整体特征的无监督特征抽取方法,并没有考虑样本的局部特征,因此EICA不利于处理人脸识别这类非线性问题的。无监督鉴别投影技术（UDP）用于高维数据压缩,其基本思想是寻找一组有效的投影方向,使得样本投影后,局部散度最小同时非局部散度最大。UDP同时考虑到样本的局部特征和非局部特征,能够反映样本内在的数据关系,因此UDP能够对样本有效地分类。提出了一种增强的无监督人脸鉴别技术,该方法结合了EICA和UDP的优点,能够：（1）反映样本高阶统计特征;（2）发掘样本内在的几何结构,从而有利于分类。在Yale人脸库和FERET人脸库上的实验验证了该算法的有效性。     

Image covariance-based subspace method for face recognition

This paper proposes a new subspace method that is based on image covariance obtained from windowed features of images. A windowed input feature consists of a number of pixels, and the dimension of input space is determined by the number of windowed features. Each element of an image covariance matrix can be obtained from the inner product of two windowed features. The 2D-PCA and 2D-LDA methods are then obtained from principal component analysis and linear discriminant analysis, respectively, using the image covariance matrix. In the case of 2D-LDA, there is no need for PCA preprocessing and the dimension of subspace can be greater than the number of classes because the within-class and between-class image covariance matrices have full ranks. Comparative experiments are performed using the FERET, CMU, and ORL databases of facial images. The experimental results show that the proposed 2D-LDA provides the best recognition rate among several subspace methods in all of the tests.     

一种改进的2DPCA人脸识别方法

在小样本情况下,传统的2DPCA算法中采用的训练样本的平均值不一定就是训练样本分布的中心,为了解决这个问题,提出了一种基于样本中间值的2DPCA人脸识别算法（M2DPCA）,该算法采用训练样本的中间值代替训练样本的平均值,以此重建总体散布矩阵。在ORL和FERET人脸数据库上的实验结果证明,新方法可以有效改善识别性能,优于传统的PCA和2DPCA方法。     

A novel statistical generative model dedicated to face recognition

In this paper, a novel statistical generative model to describe a face is presented, and is applied to the face authentication task. Classical generative models used so far in face recognition, such as Gaussian Mixture Models (GMMs) and Hidden Markov Models (HMMs) for instance, are making strong assumptions on the observations derived from a face image. Indeed, such models usually assume that local observations are independent, which is obviously not the case in a face. The presented model hence proposes to encode relationships between salient facial features by using a static Bayesian Network. Since robustness against imprecisely located faces is of great concern in a real-world scenario, authentication results are presented using automatically localised faces. Experiments conducted on the XM2VTS and the BANCA databases showed that the proposed approach is suitable for this task, since it reaches state-of-the-art results. We compare our model to baseline appearance-based systems (Eigenfaces and Fisherfaces) but also to classical generative models, namely GMM, HMM and pseudo-2DHMM.     

A simple and fast representation-based face recognition method

In this paper, we propose a very simple and fast face recognition method and present its potential rationale. This method first selects only the nearest training sample, of the test sample, from every class and then expresses the test sample as a linear combination of all the selected training samples. Using the expression result, the proposed method can classify the testing sample with a high accuracy. The proposed method can classify more accurately than the nearest neighbor classification method (NNCM). The face recognition experiments show that the classification accuracy obtained using our method is usually 2–10% greater than that obtained using NNCM. Moreover, though the proposed method exploits only one training sample per class to perform classification, it might obtain a better performance than the nearest feature space method proposed in Chien and Wu (IEEE Trans Pattern Anal Machine Intell 24:1644–1649, 2002), which depends on all the training samples to classify the test sample. Our analysis shows that the proposed method achieves this by modifying the neighbor relationships between the test sample and training samples, determined by the Euclidean metric.     

A novel weighted fuzzy LDA for face recognition using the genetic algorithm

Fuzzy linear discriminate analysis (FLDA), the principle of which is the remedy of class means via fuzzy optimization, is proven to be an effective feature extraction approach for face recognition. However, some of the between-class distances in the projected space after FLDA may be too small, which can render some classes inseparable. In this paper we propose a weighted FLDA approach that aims to increase the smallest of the between-class distances. This is accomplished by introducing some weighting coefficients to the between-class distances in FLDA. Since the optimal selection of these weighting coefficients is not tractable via standard optimization techniques, the genetic algorithm is adopted as an alternative solution in this paper. The experimental results on some benchmark data sets reveal that the proposed weighted fuzzy LDA can improve the worst recognition rate effectively and also exceed LDA and FLDA’s average performance index.     

A novel framework for automatic 3D face recognition using quality assessment

The quality of biometric samples plays an important role in biometric authentication systems because it has a direct impact on verification or identification performance. In this paper, we present a novel 3D face recognition system which performs quality assessment on input images prior to recognition. More specifically, a reject option is provided to allow the system operator to eliminate the incoming images of poor quality, e.g. failure acquisition of 3D image, exaggerated facial expressions, etc.. Furthermore, an automated approach for preprocessing is presented to reduce the number of failure cases in that stage. The experimental results show that the 3D face recognition performance is significantly improved by taking the quality of 3D facial images into account. The proposed system achieves the verification rate of 97.09% at the False Acceptance Rate (FAR) of 0.1% on the FRGC v2.0 data set.