Pong Chi Yuen

Face representation using independent component analysis

Abstract This paper addresses the problem of face recognition using independent component analysis (ICA). More specifically, we are going to address two issues on face representation using ICA. First, as the independent components (ICs) are independent but not orthogonal, images outside a training set cannot be projected into these basis functions directly. In this paper, we propose a least-squares solution method using Householder Transformation to find a new representation. Second, we demonstrate that not all ICs are useful for recognition. Along this direction, we design and develop an IC selection algorithm to find a subset of ICs for recognition. Three public available databases, namely, MIT AI Laboratory, Yale University and Olivette Research Laboratory, are selected to evaluate the performance and the results are encouraging.

A novel incremental principal component analysis and its application for face recognition

Principal component analysis (PCA) has been proven to be an efficient method in pattern recognition and image analysis. Recently, PCA has been extensively employed for face-recognition algorithms, such as eigenface and fisherface. The encouraging results have been reported and discussed in the literature. Many PCA-based face-recognition systems have also been developed in the last decade. However, existing PCA-based face-recognition systems are hard to scale up because of the computational cost and memory-requirement burden. To overcome this limitation, an incremental approach is usually adopted. Incremental PCA (IPCA) methods have been studied for many years in the machine-learning community. The major limitation of existing IPCA methods is that there is no guarantee on the approximation error. In view of this limitation, this paper proposes a new IPCA method based on the idea of a singular value decomposition (SVD) updating algorithm, namely an SVD updating-based IPCA (SVDU-IPCA) algorithm. In the proposed SVDU-IPCA algorithm, we have mathematically proved that the approximation error is bounded. A complexity analysis on the proposed method is also presented. Another characteristic of the proposed SVDU-IPCA algorithm is that it can be easily extended to a kernel version. The proposed method has been evaluated using available public databases, namely FERET, AR, and Yale B, and applied to existing face-recognition algorithms. Experimental results show that the difference of the average recognition accuracy between the proposed incremental method and the batch-mode method is less than 1%. This implies that the proposed SVDU-IPCA method gives a close approximation to the batch-mode PCA method

Incremental Linear Discriminant Analysis for Face Recognition

Dimensionality reduction methods have been successfully employed for face recognition. Among the various dimensionality reduction algorithms, linear (Fisher) discriminant analysis (LDA) is one of the popular supervised dimensionality reduction methods, and many LDA-based face recognition algorithms/systems have been reported in the last decade. However, the LDA-based face recognition systems suffer from the scalability problem. To overcome this limitation, an incremental approach is a natural solution. The main difficulty in developing the incremental LDA (ILDA) is to handle the inverse of the within-class scatter matrix. In this paper, based on the generalized singular value decomposition LDA (LDA/GSVD), we develop a new ILDA algorithm called GSVD-ILDA. Different from the existing techniques in which the new projection matrix is found in a restricted subspace, the proposed GSVD-ILDA determines the projection matrix in full space. Extensive experiments are performed to compare the proposed GSVD-ILDA with the LDA/GSVD as well as the existing ILDA methods using the face recognition technology face database and the Carneggie Mellon University Pose, Illumination, and Expression face database. Experimental results show that the proposed GSVD-ILDA algorithm gives the same performance as the LDA/GSVD with much smaller computational complexity. The experimental results also show that the proposed GSVD-ILDA gives better classification performance than the other recently proposed ILDA algorithms.

Human face recognition using PCA on wavelet subband

Together with the growing interest in the development of human and computer interface and biometric identification, human face recognition has become an active research area since early 1990. Nowadays, principal component analysis (PCA) has been widely adopted as the most promising face recognition algorithm. Yet still, traditional PCA approach has its limitations: poor discrimi- natory power and large computational load. In view of these limita- tions, this article proposed a subband approach in using PCA— apply PCA on wavelet subband. Traditionally, to represent the human face, PCA is performed on the whole facial image. In the proposed method, wavelet transform is used to decompose an im- age into different frequency subbands, and a midrange frequency subband is used for PCA representation. In comparison with the traditional use of PCA, the proposed method gives better recogni- tion accuracy and discriminatory power; further, the proposed method reduces the computational load significantly when the im- age database is large, with more than 256 training images. This article details the design and implementation of the proposed method, and presents the encouraging experimental results.

Multi-cues eye detection on gray intensity image

Abstract This paper presents a novel eye detection method for gray intensity image. The precise eye position can be located if the eye windows are accurately detected. The proposed method uses multi-cues for detecting eye windows from a face image. Three cues from the face image are used. Each cue indicates the positions of the potential eye windows. The first cue is the face intensity because the intensity of eye regions is relatively low. The second cue is based on the estimated direction of the line joining the centers of the eyes. The third cue is from the response of convolving the proposed eye variance filter with the face image. Based on the three cues, a cross-validation process is performed. This process generates a list of possible eye window pairs. For each possible case, variance projection function is used for eye detection and verification. A face database from MIT AI laboratory, which contains 930 face images with different orientations and hairstyles captured from different people, is used to evaluate the proposed system. The detection accuracy is 92.5%.

Variance projection function and its application to eye detection for human face recognition

Abstract We present a new approach for eye detection using the variance projection function. The variance projection function is developed and employed to locate landmarks of the human eye which are then used to guide the detection of the eye position and shape. A number of eye images are selected to evaluate the capability of the proposed method and the results are encouraging.

Regularized discriminant analysis and its application to face recognition

The linear (Fisher) discriminant analysis (LDA) is a well-known and popular statistical method in pattern recognition and classi5cation. The basic idea is to optimize the discriminant criteria, in which the ratio between the interand the intra-class distance is maximized. This approach is theoretically sound and a number of papers have shown its superior performance when applying in pattern-recognition applications [1–5]. However, this approach su;ers from the small-size problem. This problem occurs when the sample size is small compared with the size of feature vector, which always appears in the face-recognition applications. This is because the typical image dimension for face image is greater than 32× 32 and usually, only 2–6 images are used for training. Thus, the within-class covariance estimation Cw will be singular. In this case, the eigenvalue problem is ill-posed. The Fisher index, In(T ), will be reached at the null space of Cw and will always result in in5nity index, In(T ) → ∞. A number of methods have been proposed in the last decade to overcome the limitation of LDA on small sample size. These methods, in applying to face recognition, can be roughly grouped into three categories. The 5rst approach applied a dimension reduction method, such as principal component analysis (PCA), to extract important components for LDA. This approach is straightforward but the dimension reduction method may remove some useful information for recognition. The second approach modi5es the Fisher’s optimization criteria. Theoretically, this approach can solve the problem but the constraints [1–3] will limit the

Very Low Resolution Face Recognition Problem

This paper addresses the very low resolution (VLR) problem in face recognition in which the resolution of face image to be recognized is lower than 16×16. The VLR problem happens in many surveillance camera-based applications and existing face recognition algorithms are not able to give satisfactory performance on VLR face image. While face super-resolution (SR) methods can be employed to enhance the resolution of the images, the existing learning-based face SR methods do not perform well on such a very low resolution face image. To overcome this problem, this paper models the SR problem under VLR case as a regression problem with two constraints. First, a new data constraint is design to perform the error measurement on high resolution image space which provides more detailed and discriminative information. Second, discriminative constraint is proposed and incorporated in the training stage so that the reconstructed HR image has higher discriminability. CMU-PIE, FRGC and surveillant camera face (SCface) databases are selected for experiments. Experimental results show that the proposed method outperforms the existing methods, in terms of image quality and recognition accuracy.

Kernel machine-based one-parameter regularized Fisher discriminant method for face recognition

This paper addresses two problems in linear discriminant analysis (LDA) of face recognition. The first one is the problem of recognition of human faces under pose and illumination variations. It is well known that the distribution of face images with different pose, illumination, and face expression is complex and nonlinear. The traditional linear methods, such as LDA, will not give a satisfactory performance. The second problem is the small sample size (S3) problem. This problem occurs when the number of training samples is smaller than the dimensionality of feature vector. In turn, the within-class scatter matrix will become singular. To overcome these limitations, this paper proposes a new kernel machine-based one-parameter regularized Fisher discriminant (K1PRFD) technique. K1PRFD is developed based on our previously developed one-parameter regularized discriminant analysis method and the well-known kernel approach. Therefore, K1PRFD consists of two parameters, namely the regularization parameter and kernel parameter. This paper further proposes a new method to determine the optimal kernel parameter in RBF kernel and regularized parameter in within-class scatter matrix simultaneously based on the conjugate gradient method. Three databases, namely FERET, Yale Group B, and CMU PIE, are selected for evaluation. The results are encouraging. Comparing with the existing LDA-based methods, the proposed method gives superior results.

A Hybrid Approach for Generating Secure and Discriminating Face Template

Biometric template protection is one of the most important issues in deploying a practical biometric system. To tackle this problem, many algorithms, that do not store the template in its original form, have been reported in recent years. They can be categorized into two approaches, namely biometric cryptosystem and transform-based. However, most (if not all) algorithms in both approaches offer a trade-off between the template security and matching performance. Moreover, we believe that no single template protection method is capable of satisfying the security and performance simultaneously. In this paper, we propose a hybrid approach which takes advantage of both the biometric cryptosystem approach and the transform-based approach. A three-step hybrid algorithm is designed and developed based on random projection, discriminability-preserving (DP) transform, and fuzzy commitment scheme. The proposed algorithm not only provides good security, but also enhances the performance through the DP transform. Three publicly available face databases, namely FERET, CMU-PIE, and FRGC, are used for evaluation. The security strength of the binary templates generated from FERET, CMU-PIE, and FRGC databases are 206.3, 203.5, and 347.3 bits, respectively. Moreover, noninvertibility analysis and discussion on data leakage of the proposed hybrid algorithm are also reported. Experimental results show that, using Fisherface to construct the input facial feature vector (face template), the proposed hybrid method can improve the recognition accuracy by 4%, 11%, and 15% on the FERET, CMU-PIE, and FRGC databases, respectively. A comparison with the recently developed random multispace quantization biohashing algorithm is also reported.