Incremental robust principal component analysis for face recognition using ridge regression

Face recognition efficiency is extremely challenged by image corruption, noise, shadowing and variant face expressions. In this paper, we propose a reliable incremental face recognition algorithm to address this problem. The algorithm is robust to face image misalignment, occlusion, corruption and different style variations. To apply this for large face data streams, the proposed algorithm uses incremental robust principal component analysis (PCA) to regain the intrinsic data of a bunch of images regarding one subject. A novel similarity metric is defined for face recognition and classification. Five different databases and a base of four different criteria are used in the experiments to illustrate the reliability of the proposed method. Experiments point that it outperforms other existing incremental PCA approaches namely incremental singular value decomposition, add block singular value decomposition and candid covariance-free incremental PCA in terms of recognition rate under occlusions, facial expressions and image perspectives.

Principal component analysis (PCA) is a well-established technique in image processing and pattern recognition. Incremental PCA and robust PCA are two interesting problems with numerous potential applications. However, these two issues have only been separately addressed in the previous studies. In this paper, we present a novel algorithm for incremental and robust PCA by seamlessly integrating the two issues together. The proposed algorithm has the advantages of both incremental PCA and robust PCA. Moreover, unlike most M-estimation based robust algorithms, it is computational efficient. Experimental results on dynamic background modelling are provided to show the performance of the algorithm with a comparison to the conventional batch-mode and nonrobust algorithms.

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.

Face recognition has received significant attention in the past decades due to its potential applications in biometrics, information security, law enforcement, etc. Numerous methods have been suggested to address this problem [1]. Among appearance-based holistic approaches, principal component analysis (PCA) turns out to be very effective. As a classical unsupervised learning and data analysis technique, PCA was first used to represent images of human faces by Sirovich and Kirby in 1987 [2, 3]. Subsequently, Turk and Pentland [4, 5] applied PCA to face recognition and presented the well-known Eigenfaces method in 1991. Since then, PCA has been widely investigated and has become one of the most successful approaches to face recognition [6-15]. PCA-based image representation and analysis technique is based on image vectors. That is, before applying PCA, the given 2D image matrices must be mapped into 1D image vectors by stacking their columns (or rows). The resulting image vectors generally lead to a highdimensional image vector space. In such a space, calculating the eigenvectors of the covariance matrix is a critical problem deserving consideration. When the number of training samples is smaller than the dimension of images, the singular value decomposition (SVD) technique is useful for reducing the computational complexity [1-4]. However, when the training sample size becomes large, the SVD technique is helpless. To deal with this problem, an incremental principal component analysis (IPCA) technique has been proposed recently [16]. But, the efficiency of this algorithm still depends on the distribution of data. Over the last few years, two PCA-related methods, independent component analysis (ICA) [17] and kernel principal component analysis (KPCA) [18, 19] have been of wide concern. Bartlett [20], Yuen [21], Liu [22], and Draper [23] proposed using ICA for face representation and found that it was better than PCA when cosine was used as the similarity measure (however, the performance difference between ICA and PCA was not significant if the Euclidean distance is used [23]). Yang [24] and Liu [25] used KPCA for face feature extraction and recognition and showed that KPCA outperforms the classical PCA. Like PCA, ICA and KPCA both follow the matrix-to-vector mapping strategy when they are used for image analysis and, their algorithms are more complex than PCA. So, ICA and KPCA are considered to be computationally more expensive than PCA. The experimental results in 16

Overview of principal component analysis algorithm

Human face recognition plays a significant role in security applications for access control and real time video surveillance systems, and robotics. Popular approaches for face recognition, such as principal components analysis (PCA), rely on static datasets where training is carried in a batch-mode on a pre-available image set. Real world applications require that the training set be dynamic of evolving nature where within the framework of continuous learning new training images are continuously added to the original set; this would trigger a costly frequent re-computation of the eigen space representation via repeating an entire batch-based training that includes the new images. Incremental PCA methods allow adding new images and updating the PCA representation, and offer the advantage of dispensing with the recently added images after model update. In this paper, various incremental PCA (IPCA) training and relearning strategies are proposed and applied to the candid covariance-free incremental principal component algorithm. The effect of the number of increments and size of the eigen vectors on the correct rate of recognition are studied. The results suggest that batch PCA is inferior to the four considered IPCA1-4, and that all IPCAs are practically equivalent with IPCA3 yielding slightly better results than the other IPCAs.

Feature extraction plays an important role in face recognition system as it can reduce dimensions and reserve the most significant features which need to be classified and recognized. Principal Component Analysis (PCA) has been one of the popular techniques that used in pattern recognition related research areas. Researches have been also carried out to improve the performance of this technique, mainly based on tensor type and incremental type. Incremental Bi-Directional Principal Component Analysis (IBDPCA) is one of the latest improved versions of PCA which combined the merits from tensor and incremental type. However, IBDPCA lacks of the moderations between the latest and previous data when updating the means. This can leads to difficulty in evaluating the data accurately due to larger size of previous data, and also more memory waste. This paper proposed a technique which overcomes the limitations by adopting the IBDPCA with forgetting factors, in order to downweight the previous overloaded data with relevant factors. To evaluate the proposed technique, two experiments were carried out to compare it with IBDPCA on two different databases: FERET and CMU PIE. The experiment results indicate the better performance in recognition rate by using the proposed algorithm. Keywords—Principal Component Analysis, incremental, forgetting factors, PCA, IBDPCA

This article describes an effective human face recognition algorithm. Even though the principle component analysis (PCA) is one of the most common feature extraction methods, it is not suitable to implement a real-time embedded system for face recognition because large amount of computational load and memory capacity are necessary. To overcome this problem, we employ the incremental two-directional two-dimensional PCA (I(2D)2PCA) which is a combination of the (2D)2PCA to demand much less computational complexity than the conventional PCA and the incremental PCA (IPCA) to adapt the eigenspace only by using a new incoming sample datum without reusing of all the previous trained data. Furthermore, the modified census transform (MCT), a local normalization method useful for real-world application and implementation in an embedded system, is adopted to address robustness to illumination variations. To achieve better recognition accuracy with less computational load, the processed features are classified by the compressive sensing approach using l2–minimization. Experimental results on the Yale Face Database B show that the described system using the l2–minimization-based classification method for input data processed by the I(2D)2PCA and the MCT provided efficient and robust face recognition. © 2013 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 23, 133–139, 2013

Mass spectrometry imaging (MSI) is constantly improving in spatial resolving power, throughput and mass resolution. Although beneficial, these improvements increase data set size and content. The larger data requires correspondingly fast computer-based analyses. However, these analyses often do not scale well with increased data size. Principal component analysis (PCA) is an important analytical tool commonly used with MSI data; however, most PCA algorithms load and process the entire data set within random access memory (RAM) which is most often insufficient for large data sets. PCA algorithms that use less RAM than the data set exist but are usually much slower or sacrifice precision and are rarely used for MSI data processing. Incremental PCA (IPCA) is an alternative algorithm that avoids large RAM allocations while also preserving speed and analytical precision. Here, we demonstrate and benchmark the use of differing implementations of IPCA, PCA, and commercial software on large and often complex MSI data sets. We show that using an already-published Python-based IPCA algorithm, IPCA can be successfully applied to MSI data sets too large to fit with RAM. Furthermore, our benchmarks demonstrate that, contrary to expectations, IPCA is faster than all other tested PCA implementations on all large data sets that can be directly compared.

Principal component analysis (PCA) has been successfully employed for face recognition. However, if the training process occurs frequently, owing to the update or downdate of the face images used for training, batch PCA becomes prohibitively expensive to recalculate. To overcome this limitation, incremental principal component analysis (IPCA) and decremental principal component analysis (DPCA) can be utilized as a good alternative to PCA because it reuses their previous results for its updates. Many IPCA or DPCA algorithms have been proposed; however, inaccurate tracking of the mean values of the face image data accumulates decomposition errors, which results in poor performance compared with batch PCA. We proposed faster and more accurate algorithms for IPCA and DPCA that maintain accurate decomposition results. The experimental results reveal that the proposed algorithms produce eigenvectors that are significantly close to the eigenvectors of batch PCA and exhibit faster execution speed for face recognition.

Traditional shape learning of medical image data has been implemented via Principal Component Analysis (PCA). These PCA based statistical shape models batch process all shapes at once to generate a fixed model of shape variation as principal components, which may require significant computation resources for large number of shapes. This paper applies incremental PCA (IPCA) on a dataset of 728 surfaces (derived from magnetic resonance imaging examinations displaying the articulating bones of the knee joint) that can efficiently adapt to changes in training sets. After comparing the compactness and the accuracy of shape reconstruction of both batch PCA and IPCA models, our results show that IPCA produces a model comparable to batch PCA in terms of compactness and applicability to shape reconstruction, while requiring considerably shorter processing time and computer memory for computation.

This paper presents a robust algorithm to recognize human faces efficiently. Although the principle component analysis (PCA) is one of the most popular feature extraction methods, it requires too much computational load and memory capacity to implement a real-time embedded system for face recognition. To overcome the drawback, we employ the incremental two-directional two-dimensional PCA (I(2D) <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> PCA) which combines (2D) <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> PCA to demand much less computational complexity than the conventional PCA and the incremental PCA (IPCA) to adapt the eigenspace only using a new incoming sample datum without memorizing all of the previous trained data. In addition, robustness to illumination variations is addressed by introducing the modified census transform (MCT) which is a local normalization method useful for real-world application and implementation in an embedded system. Experimental results on the Yale Face Database B demonstrate that the proposed method based on the I(2D) <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> PCA with MCT preprocessing provided efficient and robust face recognition.

Fault detection in time-varying chemical process through incremental principal component analysis

Face recognition is a challenging research problem with several critical applications. Incremental Learning is an approach which does not require all the training samples beforehand for model development. In this direction, a popular approach called incremental principal component analysis (IPCA) was suggested by Chandrashekara et al. Later, several variants of IPCA were suggested by various researchers from time to time. However, it is not clear which of these methods are better for face recognition. To determine this, in this paper, we have performed extensive experiments on two publicly available face datasets, i.e. AR and ORL. The performance of the methods is determined in terms of average classification accuracy and average training time. IPCA and its 11 variants as suggested in the literature are considered for comparison. It has been found that there is no clear winner among the compared methods. However, the performance of MCT-based incremental two-dimensional two-directional PCA (MI(2D)\(^2\)PCA), incremental indefinite kernel PCA (IIKPCA), incremental two-dimensional kernel PCA (I2DKPCA), and incremental two-dimensional PCA (I2DPCA) methods is comparable and better than rest of the methods.

In the previous work, we have proposed a new approach to pattern recognition tasks, in which not only a classifier but also a feature space is trained incrementally. To implement this idea, Incremental Principal Component Analysis (IPCA) and Evolving Clustering Method (ECM) were effectively combined. However, the original IPCA only gives a way to determine the increase of a new feature based on a threshold value, whose value must be optimized for different datasets. In this paper, to alleviate the dependency on datasets, the accumulation ratio is introduced as its criterion, and an improved algorithm of IPCA is derived. To see if correct feature construction is carried out by this new IPCA algorithm, the classification performance is evaluated over some standard datasets when Evolving Clustering Method (ECM) is adopted as a prototype learning method for Nearest Neighbor classifier. Our simulation results show that the proposed IPCA works well without elaborating sensitive parameter optimization and its recognition accuracy outperforms that of the previous model.