Feature extraction using maximum variance sparse mapping

In this paper, a multiple sub-manifold learning method–oriented classification is presented via sparse representation, which is named maximum variance sparse mapping. Based on the assumption that data with the same label locate on a sub-manifold and different class data reside in the corresponding sub-manifolds, the proposed algorithm can construct an objective function which aims to project the original data into a subspace with maximum sub-manifold distance and minimum manifold locality. Moreover, instead of setting the weights between any two points directly or obtaining those by a square optimal problem, the optimal weights in this new algorithm can be approached using L1 minimization. The proposed algorithm is efficient, which can be validated by experiments on some benchmark databases.     

Feature extraction based on Laplacian bidirectional maximum margin criterion

Maximum margin criterion (MMC) based feature extraction is more efficient than linear discriminant analysis (LDA) for calculating the discriminant vectors since it does not need to calculate the inverse within-class scatter matrix. However, MMC ignores the discriminative information within the local structures of samples and the structural information embedding in the images. In this paper, we develop a novel criterion, namely Laplacian bidirectional maximum margin criterion (LBMMC), to address the issue. We formulate the image total Laplacian matrix, image within-class Laplacian matrix and image between-class Laplacian matrix using the sample similar weight that is widely used in machine learning. The proposed LBMMC based feature extraction computes the discriminant vectors by maximizing the difference between image between-class Laplacian matrix and image within-class Laplacian matrix in both row and column directions. Experiments on the FERET and Yale face databases show the effectiveness of the proposed LBMMC based feature extraction method.     

A multi-manifold discriminant analysis method for image feature extraction

In this paper, we propose a Multi-Manifold Discriminant Analysis (MMDA) method for an image feature extraction and pattern recognition based on graph embedded learning and under the Fisher discriminant analysis framework. In an MMDA, the within-class graph and between-class graph are, respectively, designed to characterize the within-class compactness and the between-class separability, seeking for the discriminant matrix to simultaneously maximize the between-class scatter and minimize the within-class scatter. In addition, in an MMDA, the within-class graph can represent the sub-manifold information, while the between-class graph can represent the multi-manifold information. The proposed MMDA is extensively examined by using the FERET, AR and ORL face databases, and the PolyU finger-knuckle-print databases. The experimental results demonstrate that an MMDA is effective in feature extraction, leading to promising image recognition performance.     

Feature extraction using fuzzy inverse FDA

This paper proposes a new method of feature extraction and recognition, namely, the fuzzy inverse Fisher discriminant analysis (FIFDA) based on the inverse Fisher discriminant criterion and fuzzy set theory. In the proposed method, a membership degree matrix is calculated using FKNN, then the membership degree is incorporated into the definition of the between-class scatter matrix and within-class scatter matrix to get the fuzzy between-class scatter matrix and fuzzy within-class scatter matrix. Experimental results on the ORL, FERET face databases and pulse signal database show that the new method outperforms Fisherface, fuzzy Fisherface and inverse Fisher discriminant analysis.     

Feature extraction and image segmentation using self-organizing networks

Feature extraction and image segmentation (FEIS) are two primary goals of almost all image-understanding systems. They are also the issues at which we look in this paper. We think of FEIS as a multilevel process of grouping and describing at each level. We emphasize the importance of grouping during this process because we believe that many features and events in real images are only perceived by combining weak evidence of several organized pixels or other low-level features. To realize FEIS based on this formulation, we must deal with such problems as how to discover grouping rules, how to develop grouping systems to integrate grouping rules, how to embed grouping processes into FEIS systems, and how to evaluate the quality of extracted features at various levels. We use self-organizing networks to develop grouping systems that take the organization of human visual perception into consideration. We demonstrate our approach by solving two concrete problems: extracting linear features in digital images and partitioning color images into regions. We present the results of experiments on real images.     

Orthogonal vs. uncorrelated least squares discriminant analysis for feature extraction

In this paper, a new discriminant analysis for feature extraction is derived from the perspective of least squares regression. To obtain great discriminative power between classes, all the data points in each class are expected to be regressed to a single vector, and the basic task is to find a transformation matrix such that the squared regression error is minimized. To this end, two least squares discriminant analysis methods are developed under the orthogonal or the uncorrelated constraint. We show that the orthogonal least squares discriminant analysis is an extension to the null space linear discriminant analysis, and the uncorrelated least squares discriminant analysis is exactly equivalent to the traditional linear discriminant analysis. Comparative experiments show that the orthogonal one is more preferable for real world applications.     

Feature extraction method for a robot map using neural networks

Many map-building algorithms using ultrasonic sensors have been developed for mobile robot applications. In indoor environments, the ultrasonic sensor system gives some uncertain data. To compensate for this effect, a new feature extraction method using neural networks is proposed. A new, effective representation of the target is defined, and the reflection wave data patterns are learnt using neural networks. As a consequence, the targets are classified as planes, corners, or edges, which all frequently occur in indoor environments. We constructed our own robot system for the experiments which were carried out to show the performance. This work was presented in part at the 7th International Symposium on Artificial Life and Robotics, Oita, Japan, January 16–18, 2002     

Feature extraction for fingerprint classification

This paper presents two algorithms for smoothing and feature extraction for fingerprint classification. Deutsch's⁽²⁾ Thinning algorithm (rectangular array) is used for thinning the digitized fingerprint (binary version). A simple algorithm is also suggested for classifying the fingerprints. Experimental results obtained using such algorithms are presented.     

Feature extraction by learning Lorentzian metric tensor and its extensions

We develop a supervised dimensionality reduction method, called Lorentzian discriminant projection (LDP), for feature extraction and classification. Our method represents the structures of sample data by a manifold, which is furnished with a Lorentzian metric tensor. Different from classic discriminant analysis techniques, LDP uses distances from points to their within-class neighbors and global geometric centroid to model a new manifold to detect the intrinsic local and global geometric structures of data set. In this way, both the geometry of a group of classes and global data structures can be learnt from the Lorentzian metric tensor. Thus discriminant analysis in the original sample space reduces to metric learning on a Lorentzian manifold. We also establish the kernel, tensor and regularization extensions of LDP in this paper. The experimental results on benchmark databases demonstrate the effectiveness of our proposed method and the corresponding extensions.     

Orthogonal local spline discriminant projection with application to face recognition

In this paper, an efficient feature extraction algorithm called orthogonal local spline discriminant projection (O-LSDP) is proposed for face recognition. Derived from local spline embedding (LSE), O-LSDP not only inherits the advantages of LSE which uses local tangent space as a representation of the local geometry so as to preserve the local structure, but also makes full use of class information and orthogonal subspace to improve discriminant power. Extensive experiments on several standard face databases demonstrate the effectiveness of the proposed method.     

基于局部保持投影的鉴别最大间距准则

提出一种基于流形学习的特征提取方法——鉴别最大间距准则。该方法采用线性投影,保留最优的局部和全局信息数据集。试图找到具有最好鉴别能力的原始信息,使类间离散度最大的同时类内离散尽可能的小。该方法在识别率上比其它方法都有较大提高,通过在YALE和JAFFE人脸库上的实验验证该方法的有效性。     

Feature extraction in Brazilian Sign Language Recognition based on phonological structure and using RGB-D sensors

In contrast to speech recognition, whose speech features have been extensively explored in the research literature, feature extraction in Sign Language Recognition (SLR) is still a very challenging problem. In this paper we present a methodology for feature extraction in Brazilian Sign Language (BSL, or LIBRAS in Portuguese) that explores the phonological structure of the language and relies on RGB-D sensor for obtaining intensity, position and depth data. From the RGB-D images we obtain seven vision-based features. Each feature is related to one, two or three structural elements in BSL. We investigate this relation between extracted features and structural elements based on shape, movement and position of the hands. Finally we employ Support Vector Machines (SVM) to classify signs based on these features and linguistic elements. The experiments show that the attributes of these elements can be successfully recognized in terms of the features obtained from the RGB-D images, with accuracy results individually above 80% on average. The proposed feature extraction methodology and the decomposition of the signs into their phonological structure is a promising method to help expert systems designed for SLR.     

Feature extraction for texture classification

We address the problem of texture classification. Random walks are simulated for plane domains $\text{A}$ bounded by absorbing boundaries Γ, and the absorption distributions are estimated. Measurements derived from the above distributions are the features used for texture classification. Experiments using such a model have been performed and the results showed a rate of accuracy of 89.7% for a data set consisting of one hundred and twenty-eight textured images equally distributed among thirty-two classes of textures.     

Complete discriminant evaluation and feature extraction in kernel space for face recognition

This work proposes a method to decompose the kernel within-class eigenspace into two subspaces: a reliable subspace spanned mainly by the facial variation and an unreliable subspace due to limited number of training samples. A weighting function is proposed to circumvent undue scaling of eigenvectors corresponding to the unreliable small and zero eigenvalues. Eigenfeatures are then extracted by the discriminant evaluation in the whole kernel space. These efforts facilitate a discriminative and stable low-dimensional feature representation of the face image. Experimental results on FERET, ORL and GT databases show that our approach consistently outperforms other kernel based face recognition methods.

Feature extraction using rough set theory and genetic algorithms—an application for the simplification of product quality evaluation

Feature extraction is an important aspect in data mining and knowledge discovery. In this paper an integrated feature extraction approach, which is based on rough set theory and genetic algorithms (GAs), is proposed. Based on this approach, a prototype feature extraction system has been established and illustrated in an application for the simplification of product quality evaluation. The prototype system successfully integrates the capability of rough set theory in handling uncertainty with a robust search engine, which is based on a GA. The results show that it can remarkably reduce the cost and time consumed on product quality evaluation without compromising the overall specifications of the acceptance tests.     

人脸识别特征提取方法和相似度匹配方法研究

横向比较特征提取方法，综合考虑认证率和特征提取时间两方面因素，该文认为特征脸结合线性判别分析方法是研究的4种特征提取方法中最优的方法。通过对投影空间维数的研究，最佳投影空间维数同数据库本身类内图像的相似程度和每一类的样本数目同方向增长，它们之间存在定性关系而非定量关系。相似度匹配方法的研究结果表明余弦距离分类器分类效果最佳。     

Feature extraction based on the Bhattacharyya distance

In this paper, we present a feature extraction method by utilizing an error estimation equation based on the Bhattacharyya distance. We propose to use classification errors in the transformed feature space, which are estimated using the error estimation equation, as a criterion for feature extraction. The construction of linear transformation for feature extraction is conducted using an iterative gradient descent algorithm, so that the estimated classification error is minimized. Due to the ability to predict error, it is possible to determine the minimum number of features required for classification. Experimental results show that the proposed feature extraction method compares favorably with conventional methods.     

Feature extraction with an improved scale-invariants for deformation digits

This paper presents an alternative formulation on improved scaled-invariants using higher order centralized moments for digits with deformations. We claim that deformation digits would be digits with improper shapes, unconstrained styles of writing and different orientations. A detail experimental evaluation of the utilizing various moments order as pattern features in recognition of handprinted and handwritten digits have been carried out using the proposed invariants. We use scale-invariants of centralized moments of order 2 for the numerator and order 4 for the denominator while preserving the scale factor of the same order. Unconstrained digits are rotated clockwise and counter clockwise of 45 degree. As a comparison, we generate geometric moment invariants on these digits. We train these invariants using standard back-propagation and modified backpropagation in the classifications phase. We found that the results are promising with an improved scaled-invariants of higher order, and the classifications of the digits are successfully recognized.     

基于判别最小二乘回归的局部保留子空间学习算法

近几年稀疏表示在降维领域的成功应用引起了人们的广泛关注。针对稀疏表示能够有效提取出相同类内部样本间和不同类之间的稀疏性,却具有高复杂度求解过程和存在丢失数据结构关键信息的缺点进行了研究,提出了判别最小二乘局部保持投影(DLSLPP)算法。DLSLPP算法利用最小二乘回归充分而完整的提取了数据之间的结构信息,同时利用最小二乘回归具有数值解的优势降低了算法的复杂度。此外,DLSLPP算法采用不同于传统算法的新型加权平均方式构造数据代表样本增强了算法的判别能力。在四个图像分类数据集和四个算法上的对比实验表明DLSLPP算法能够达到十分优异的效果。     

Global plus local: A complete framework for feature extraction and recognition

Linear discriminant analysis (LDA) is one of the most popular supervised feature extraction techniques used in machine learning and pattern classification. However, LDA only captures global geometrical structure information of the data and ignores the geometrical structure information of local data points. Though many articles have been published to address this issue, most of them are incomplete in the sense that only part of the local information is used. We show here that there are total three kinds of local information, namely, local similarity information, local intra-class pattern variation, and local inter-class pattern variation. We first propose a new method called enhanced within-class LDA (EWLDA) algorithm to incorporate the local similarity information, and then propose a complete framework called complete global–local LDA (CGLDA) algorithm to incorporate all these three kinds of local information. Experimental results on two image databases demonstrate the effectiveness of our algorithms.