Discriminative Feature Extraction Method Research Articles

Highly discriminative and adaptive feature extraction method based on NMF–MFCC for event recognition of Φ-OTDR

To enhance the capability of phase-sensitive optical time domain reflectometers (Φ-OTDR) to recognize disturbance events, an improved adaptive feature extraction method based on NMF–MFCC is proposed, which replaces the fixed filter bank used in the traditional method to extract the mel-frequency cepstral coefficient (MFCC) features by a spectral structure obtained from the Φ-OTDR signal spectrum using nonnegative matrix factorization (NMF). Three typical events on fences are set as recognition targets in our experiments, and the results show that the NMF–MFCC features have higher distinguishability, with the corresponding recognition accuracy reaching 98.47%, which is 7% higher than that using the traditional MFCC features.

Similarity-sequenced multi-view discriminant feature extraction for image recognition

Traditional multi-view feature extraction methods based on manifold learning frequently overlook the similarity sequence between samples, failing to capture the intrinsic manifold structure of raw nonlinear samples and restricting the recognition performance of multi-view learning. In this paper, we propose a novel similarity-sequenced multi-view discriminant feature extraction method, called Similarity -sequenced Multi-view Discriminant Correlation Analysis (SMDCA), which explicitly considers the sample sequences based on similarity. The method constructs similarity-sequenced discriminant scatters for preserving the sequence structure of within-class samples and develops between-class correlations with the similarity-sequence structure information for further constraining intrinsic manifold structure of cross-view samples. SMDCA can also simultaneously extract low-dimensional sequence features with well-discriminative power from multiple views. Extensive experiments exhibit that SMDCA can provide higher recognition accuracy and stronger robustness in image recognition tasks.

Discriminant Feature Extraction for Centrifugal Pump Fault Diagnosis

Raw statistical features can imitate the amplitude, average, energy and time, and frequency series distribution of a raw vibration signal. However, these raw statistical features are either not very sensitive to weak incipient faults or are unsuitable for more severe faults, thus affecting the fault detection and classification accuracy. To tackle this problem, this paper proposes a discriminant feature extraction method for Centrifugal Pump (CP) fault diagnosis. In order to obtain the discriminant feature pool, the proposed method is divided into three phases. In the first phase, a healthy baseline signal is selected. In the second phase, the healthy baseline signal is cross-correlated with the CP vibration signals of different classes, and a set of new features are extracted from the resulting correlation sequence. In the third phase, raw hybrid features in time, frequency, and the time-frequency domain are extracted from both the healthy baseline signals and the CP vibration signals of different classes. The correlation coefficient is calculated between the raw hybrid feature pools, which results in a new set of discriminant features. Discriminant features help the machine learning classifiers to effectively detect and classify the data into its respective classes. Furthermore, the proposed method combines all these features into a single feature vector that forms a vulnerable feature pool. The vulnerable feature pool describes the CP's vulnerability to a fault and is provided as an input to a multiclass support vector machine (MSVM) for CP fault detection and classification. The experimental results illustrate that the accuracy obtained from the proposed method shows promising improvements over the state-of-the-art conventional methods.

A robust geometric mean-based subspace discriminant analysis feature extraction approach for image set classification

Discriminant analysis technique is an important research topic in image set classification because it can extract discriminative features. However, most existing discriminant analysis methods almost fail to work for feature extraction of data because there is only a small amount of valid discriminant information. The main weakness of most existing discriminant analysis models is that the class mean vector is constructed by using class sample average. That is not sufficient to provide an accurate estimation of the class mean. In this paper, we proposed a robust geometric mean-based subspace discriminant analysis feature extraction method for image set classification. This method is a combination of geometric mean vector, subspace and covariance matrix to jointly represent an image set because they are contain different discriminative information. The above three representation ways lie on different spaces. To reduce the dissimilarity between the heterogeneous spaces, a robust geometric mean-based subspace discriminant analysis learning (GMSDA) framework is developed, which includes three steps operation. At first, uses a new geometric mean vector to construct geometric between-class scatter matrix (Sgb) and geometric within-class scatter matrix (Sgw) instead of traditional mean vector of many methods. Secondly, maximizes the geometric between-class scatter matrix to increase the difference between extracted features. Finally, maximizes the subspace between-class scatter (SgbS) and minimizes the subspace within-class scatter (SgwS) simultaneously in the subspace of original space. Experiments on five datasets illustrate that our proposed GMSDA method works the best in small sample size situation by using maximum likelihood classification (MLC).

Discriminative feature based on FWMW for playback speech detection

A discriminative feature extraction method for playback speech detection is proposed, it relies on the finding that frame-wise magnitude-spectrum weight (FWMW) can enlarge the difference between genuine speech and playback speech. The proposed FWMW is obtained by supplying the sum of every frame magnitude spectrum frequency bin as the weight on the frame magnitude spectrum. Then, a new feature based on FWMW is proposed, namely constant-Q weight segmentation coefficients (CQWSCs). The experimental result on ASVspoof 2017 version 2.0 evaluation set using CQWSC indicates that: (i) FWMW can make the proposed feature has more discriminative ability and the equal error rate can decline 15.53 and 19.18% under Gaussian mixture model and deep neural network, respectively, and (ii) CQWSC performs better than some commonly used features.

Flexible non-greedy discriminant subspace feature extraction

Recently, L1-norm-based non-greedy linear discriminant analysis (NLDA-L1) for feature extraction has been shown to be effective for dimensionality reduction, which obtains projection vectors by a non-greedy algorithm. However, it usually acquires unsatisfactory performances due to the utilization of L1-norm distance measurement. Therefore, in this brief paper, we propose a flexible non-greedy discriminant subspace feature extraction method, which is an extension of NLDA-L1 by maximizing the ratio of Lp-norm inter-class dispersion to intra-class dispersion. Besides, we put forward a powerful iterative algorithm to solve the resulted objective function and also conduct theoretical analysis on the algorithm. Finally, experimental results on image databases show the effectiveness of our method

Face Recognition Using Composite Features Based on Discriminant Analysis

Extracting holistic features from the whole face and extracting the local features from the sub-image have pros and cons depending on the conditions. In order to effectively utilize the strengths of various types of holistic features and local features while also complementing each weakness, we propose a method to construct a composite feature vector for face recognition based on discriminant analysis. We first extract the holistic features and the local features from the whole face image and various types of local images using the discriminant feature extraction method. Then, we measure the amount of discriminative information in the individual holistic features and local features and construct composite features with only discriminative features for face recognition. The composite features from the proposed method were compared with the holistic features, local features, and others prepared by hybrid methods through face recognition experiments for various types of face image databases. The proposed composite feature vector displayed better performance than the other methods.

Sparse coding with cross-view invariant dictionaries for person re-identification

The task of matching observations of the same person in disjoint views captured by non-overlapping cameras is known as the person re-identification problem. It is challenging owing to low-quality images, inter-object occlusions, and variations in illumination, viewpoints and poses. Unlike previous approaches that learn Mahalanobis-like distance metrics, we propose a novel approach based on dictionary learning that takes the advances of sparse coding of discriminatingly and cross-view invariantly encoding features representing different people. Firstly, we propose a robust and discriminative feature extraction method of different feature levels. The feature representations are projected to a lower computation common subspace. Secondly, we learn a single cross-view invariant dictionary for each feature level for different camera views and a fusion strategy is utilized to generate the final matching results. Experimental statistics show the superior performance of our approach by comparing with state-of-the-art methods on two publicly available benchmark datasets VIPeR and PRID 2011.

Inductive and flexible feature extraction for semi-supervised pattern categorization

This paper proposes a novel discriminant semi-supervised feature extraction method for generic classification and recognition tasks. This method, called inductive flexible semi-supervised feature extraction, is a graph-based embedding method that seeks a linear subspace close to a non-linear one. It is based on a criterion that simultaneously exploits the discrimination information provided by the labeled samples, maintains the graph-based smoothness associated with all samples, regularizes the complexity of the linear transform, and minimizes the discrepancy between the unknown linear regression and the unknown non-linear projection. We extend the proposed method to the case of non-linear feature extraction through the use of kernel trick. This latter allows to obtain a nonlinear regression function with an output subspace closer to the learned manifold than that of the linear one. Extensive experiments are conducted on ten benchmark databases in order to study the performance of the proposed methods. Obtained results demonstrate a significant improvement over state-of-the-art algorithms that are based on label propagation or semi-supervised graph-based embedding.

얼굴인식을 위한 판별분석에 기반한 복합특징 벡터 구성 방법

We propose a method to construct composite feature vector based on discriminant analysis for face recognition. For this, we first extract the holistic- and local-features from whole face images and local images, which consist of the discriminant pixels, by using a discriminant feature extraction method. In order to utilize both advantages of holistic- and local-features, we evaluate the amount of the discriminative information in each feature and then construct a composite feature vector with only the features that contain a large amount of discriminative information. The experimental results for the FERET, CMU-PIE and Yale B databases show that the proposed composite feature vector has improvement of face recognition performance.

Eye detection using discriminatory Haar features and a new efficient SVM

This paper presents an accurate and efficient eye detection method using the discriminatory Haar features (DHFs) and a new efficient support vector machine (eSVM). The DHFs are extracted by applying a discriminating feature extraction (DFE) method to the 2D Haar wavelet transform. The DFE method is capable of extracting multiple discriminatory features for two-class problems based on two novel measure vectors and a new criterion in the whitened principal component analysis (PCA) space. The eSVM significantly improves the computational efficiency upon the conventional SVM for eye detection without sacrificing the generalization performance. Experiments on the Face Recognition Grand Challenge (FRGC) database and the BioID face database show that (i) the DHFs exhibit promising classification capability for eye detection problem; (ii) the eSVM runs much faster than the conventional SVM; and (iii) the proposed eye detection method achieves near real-time eye detection speed and better eye detection performance than some state-of-the-art eye detection methods.

Bayesian common spatial patterns for multi-subject EEG classification

Multi-subject electroencephalography (EEG) classification involves algorithm development for automatically categorizing brain waves measured from multiple subjects who undergo the same mental task. Common spatial patterns (CSP) or its probabilistic counterpart, PCSP, is a popular discriminative feature extraction method for EEG classification. Models in CSP or PCSP are trained on a subject-by-subject basis so that inter-subject information is neglected. In the case of multi-subject EEG classification, however, it is desirable to capture inter-subject relatedness in learning a model. In this paper we present a nonparametric Bayesian model for a multi-subject extension of PCSP where subject relatedness is captured by assuming that spatial patterns across subjects share a latent subspace. Spatial patterns and the shared latent subspace are jointly learned by variational inference. We use an infinite latent feature model to automatically infer the dimension of the shared latent subspace, placing Indian Buffet process (IBP) priors on our model. Numerical experiments on BCI competition III IVa and IV 2a dataset demonstrate the high performance of our method, compared to PCSP and existing Bayesian multi-task CSP models.

An efficient orientation distance–based discriminative feature extraction method for multi-classification

Feature extraction is an important step before actual learning. Although many feature extraction methods have been proposed for clustering, classification and regression, very limited work has been done on multi-class classification problems. This paper proposes a novel feature extraction method, called orientation distance–based discriminative (ODD) feature extraction, particularly designed for multi-class classification problems. Our proposed method works in two steps. In the first step, we extend the Fisher Discriminant idea to determine an appropriate kernel function and map the input data with all classes into a feature space where the classes of the data are well separated. In the second step, we put forward two variants of ODD features, i.e., one-vs-all-based ODD and one-vs-one-based ODD features. We first construct hyper-plane (SVM) based on one-vs-all scheme or one-vs-one scheme in the feature space; we then extract one-vs-all-based or one-vs-one-based ODD features between a sample and each hyper-plane. These newly extracted ODD features are treated as the representative features and are thereafter used in the subsequent classification phase. Extensive experiments have been conducted to investigate the performance of one-vs-all-based and one-vs-one-based ODD features for multi-class classification. The statistical results show that the classification accuracy based on ODD features outperforms that of the state-of-the-art feature extraction methods.

CLASSIFICATION OF ROOF MATERIALS USING HYPERSPECTRAL DATA

Abstract. Mapping of surface materials in urban areas using aerial imagery is a challenging task. This is because there are numerous materials present in relatively small regions. Hyperspectral data features a fine spectral resolution and thus has a significant capability for automatic identification and mapping of urban surface materials. In this study an approach for identification of roof surface materials using hyperspectral data is presented. The study is based on an urban area in Ludwigsburg, Germany, using a HyMap data set recorded during the HyMap campaign in August, 2010. Automatisierte Liegenschaftskarte (ALK) vector data with a building layer is combined with the HyMap data to limit the analysis to roofs. A spectral library for roofs is compiled based on field and image measurements. In the roof material identification process, supervised classification methods, namely spectral angle mapper and spectral information divergence and the object oriented ECHO (extraction and classification of homogeneous objects) approach are compared. In addition to the overall shape of spectral curves, position and strength of absorptions features are used to enhance material identification. The discriminant analysis feature extraction method is applied to the HyMap data in order to identify features (band combinations) suitable for discriminating between the target classes. The identified optimal features are used to create a new data set which is later classified using the ECHO classifier. The classification results with respect to material types of roofs are presented in this study. The most important results are evaluated using orthophotos, probability maps and field visits.

Discriminative tonal feature extraction method in mandarin speech recognition

To utilize the supra-segmental nature of Mandarin tones, this article proposes a feature extraction method for hidden markov model (HMM) based tone modeling. The method uses linear transforms to project F 0 (fundamental frequency) features of neighboring syllables as compensations, and adds them to the original F 0 features of the current syllable. The transforms are discriminatively trained by using an objective function termed as “minimum tone error”, which is a smooth approximation of tone recognition accuracy. Experiments show that the new tonal features achieve 3.82% tone recognition rate improvement, compared with the baseline, using maximum likelihood trained HMM on the normal F 0 features. Further experiments show that discriminative HMM training on the new features is 8.78% better than the baseline.

Hidden space-based nonlinear discriminant feature extraction method

A novel nonlinear feature extraction method based on the scatter difference criterion in hidden space is developed. The main idea is that the original input space is first mapped into a hidden space through a hidden function, which is still referred to as the kernel function in the proposed method, and, in this space, feature extraction is conducted using the difference of between-class scatter and within-class scatter as the discriminant criterion. Different from the existing kernel-based feature extraction methods, the kernel functions used in the proposed method are not required to satisfy Mercer's theorem so that they can be chosen from a wide range. What is more important is that, due to the adoption of the scatter difference as the discriminant criterion for feature extraction, the proposed method essentially avoids the small sample size problem usually encountered in kernel Fisher discriminant analysis. Finally, extensive experiments have been performed on a subset of the FERET face database and the CENPARMI handwritten digital database. The experimental results indicate that the proposed method outperforms traditional scatter difference discriminant analysis in recognition performance.

Discriminative training approaches to fabric defect classification based on wavelet transform

Wavelet transform is able to characterize the fabric texture at multiscale and multiorientation, which provides a promising way to the classification of fabric defects. For the objective of minimum error rate in the defect classification, this paper compares six wavelet transform-based classification methods, using different discriminative training approaches to the design of the feature extractor and classifier. These six classification methods are: methods of using an Euclidean distance classifier and a neural network classifier trained by maximum likelihood method and backpropagation algorithm, respectively; methods of using an Euclidean distance classifier and a neural network classifier trained by minimum classification error method, respectively; method of using a linear transformation matrix-based feature extractor and an Euclidean distance classifier, designed by discriminative feature extraction (DFE) method; method of using an adaptive wavelet-based feature extractor and an Euclidean distance classifier, designed by the DFE method. These six approaches have been evaluated on the classification of 466 defect samples containing eight classes of fabric defects, and 434 nondefect samples. The DFE training approach using adaptive wavelet has been shown to outperform the other approaches, where 95.8% classification accuracy was achieved.

A new approach to designing a feature extractor in speaker identification based on discriminative feature extraction

This paper presents a new framework for designing a feature extractor in a speaker identification system based on the discriminative feature extraction (DFE) method. In order to find the frequency scale appropriate for accurate speaker identification, a mel-cepstral estimation technique using a second-order all-pass warping function is applied to the feature extractor; the frequency warping parameters and the text-independent speaker model parameters are jointly optimized based on a minimum classification error (MCE) criterion. Experimental results show that the frequency scale after optimization is different from traditional Linear/Mel scales and the proposed system outperforms conventional systems in which only the classifier is optimized with the MCE criterion.

Discriminative feature weighting for HMM-based continuous speech recognizers

The Discriminative Feature Extraction (DFE) method provides an appropriate formalism for the design of the front-end feature extraction module in pattern classification systems. In the recent years, this formalism has been successfully applied to different speech recognition problems, like classification of vowels, classification of phonemes or isolated word recognition. The DFE formalism can be applied to weight the contribution of the components in the feature vector. This variant of DFE, that we call Discriminative Feature Weighting (DFW), improves the pattern classification systems by enhancing those components more relevant for the discrimination among the different classes. This paper is dedicated to the application of the DFW formalism to Continuous Speech Recognizers (CSR) based on Hidden Markov Models (HMMs). Two different types of HMM-based speech recognizers are considered: recognizers based on Discrete-HMMs (DHMMs) (for which the acoustic evaluation is based on an Euclidean distance measure) and Semi-Continuous-HMMs (SCHMMs) (for which the acoustic evaluation is performed making use of a mixture of multivariated Gaussians). We report how the components can be weighted and how the weights can be discriminatively trained and applied to the speech recognizers. We present recognition results for several continuous speech recognition tasks. The experimental results show the utility of DFW for HMM-based continuous speech recognizers.