掌纹识别算法综述

掌纹识别作为一种新兴的生物识别技术, 近年来得到了广泛的关注与研究. 与其他生物特征相比, 掌纹有许多独特的优势,包括识别率高、采集设备价格低廉、用户可接受性好等. 这些优势使得掌纹识别成为一种有着广泛应用前景的生物识别方法. 本文首先介绍了掌纹的特点、掌纹的采集设备和预处理方法, 之后详细介绍了近几年来提出的各种掌纹识别方法. 根据特征提取以及匹配方法的不同, 本文将掌纹识别方法分为基于结构的、基于子空间的、基于编码的和基于统计的四类方法. 在回顾和比较了各种算法的特点之后, 对未来的掌纹识别方法的发展方向作了展望.     

Robust palmprint identification based on directional representations and compressed sensing

In this paper, we propose a novel approach for palmprint recognition, which contains two interesting components: directional representation and compressed sensing. Gabor wavelets can be well represented for biometric image for their similar characteristics to human visual system. However, these Gabor-based algorithms are not robust for image recognition under non-uniform illumination and suffer from the heavy computational burden. To improve the recognition performance under the low quality conditions with a fast operation speed, we propose novel palmprint recognition approach using directional representations. Firstly, the directional representation for palmprint appearance is obtained by the anisotropy filter, which is robust to drastic illumination changes and preserves important discriminative information. Then, the principal component analysis (PCA) is used for feature extraction to reduce the dimensions of the palmprint images. At last, based on a sparse representation on PCA feature, the compressed sensing is used to distinguish palms from different hands. Experimental results on the PolyU palmprint database show the proposed algorithm have better performance than that of the Gabor based methods.     

Online palmprint identification

Biometrics-based personal identification is regarded as an effective method for automatically recognizing, with a high confidence, a person's identity. This paper presents a new biometric approach to online personal identification using palmprint technology. In contrast to the existing methods, our online palmprint identification system employs low-resolution palmprint images to achieve effective personal identification. The system consists of two parts: a novel device for online palmprint image acquisition and an efficient algorithm for fast palmprint recognition. A robust image coordinate system is defined to facilitate image alignment for feature extraction. In addition, a 2D Gabor phase encoding scheme is proposed for palmprint feature extraction and representation. The experimental results demonstrate the feasibility of the proposed system.     

Robust palmprint verification using 2D and 3D features

This paper presents a new personal authentication system that simultaneously exploits 2D and 3D palmprint features. The objective of our work is to improve accuracy and robustness of existing palmprint authentication systems using 3D palmprint features. The proposed multilevel framework for personal authentication efficiently utilizes the robustness (against spoof attacks) of the 3D features and the high discriminating power of the 2D features. The developed system uses an active stereo technique, structured light, to simultaneously capture 3D image or range data and a registered intensity image of the palm. The surface curvature feature based method is investigated for 3D palmprint feature extraction while Gabor feature based competitive coding scheme is used for 2D representation. We comparatively analyze these representations for their individual performance and attempt to achieve performance improvement using the proposed multilevel matcher that utilizes fixed score level combination scheme to integrate information. Our experiments on a database of 108 subjects achieved significant improvement in performance with the integration of 3D features as compared to the case when 2D palmprint features alone are employed. We also present experimental results to demonstrate that the proposed biometric system is extremely difficult to circumvent, as compared to the currently proposed palmprint authentication approaches in the literature.     

指节纹识别综述*

相比其它生物特征,指节纹具有特征丰富,采集设备价格低,易于结合手形、手指静脉及掌纹组成性能鲁棒的多模态识别系统等优点.文中首先介绍指节纹的定义、数据采集、预处理方法等,之后详细介绍各种指节纹识别算法及多模态识别方案.根据特征提取及匹配方法的不同,将指节纹识别算法分为6类:基于结构的算法、基于子空间学习的算法、基于编码的算法、基于纹理特征的算法、基于相关滤波器的算法和基于局部特征描述子的算法.回顾和总结各种算法的特点,展望未来指节纹识别的发展方向.     

主成分分析法在掌纹图像识别中的应用

掌纹识别技术是生物特征识别领域的又一新兴技术,在网络安全、身份鉴别等方面有广阔的应用前景。将主成分分析法应用于掌纹图像的特征提取,阐释了传统主成分分析与加权主成分分析在处理掌纹图像时的差异,并在不同数据库上对两种方法进行了实验,结果表明传统主成分分析比加权主成分分析有更高的识别率以及加权主成分分析能够削弱光照对识别结果的影响。     

Weighted linear embedding: utilizing local and nonlocal information sufficiently

Local discriminant embedding (LDE) only utilizes the local information and ignores the nonlocal information. Although linear discriminant analysis (LDA) utilizes the local information and the nonlocal information simultaneously, it treats these two kinds of information equally. As we know, the local information and the nonlocal information are both effective for feature extraction, but they have different roles in feature extraction. To utilize the local information and the nonlocal information simultaneously and utilize them distinctively, a new feature extraction approach called weighted linear embedding (WLE) is proposed by using the Gaussian weighting. Further, a method to set the optimal parameter of the Gaussian weighting is put forward. WLE is evaluated on YALE, FERET face databases, the PolyU palmprint database, and the PolyU finger-knuckle-print database. The experimental results demonstrate the effectiveness of WLE.     

Orientation selection using modified FCM for competitive code-based palmprint recognition

Coding-based methods are among the most promising palmprint recognition methods because of their small feature size, fast matching speed and high verification accuracy. The competitive coding scheme, one representative coding-based method, first convolves the palmprint image with a bank of Gabor filters with different orientations and then encodes the dominant orientation into its bitwise representation. Despite the effectiveness of competitive coding, few investigations have been given to study the influence of the number of Gabor filters and the orientation of each Gabor filter. In this paper, based on the statistical orientation distribution and the orientation separation characteristics, we propose a modified fuzzy C-means cluster algorithm to determine the orientation of each Gabor filter. Since the statistical orientation distribution is based on a set of real palmprint images, the proposed method is more suitable for palmprint recognition. Experimental results indicate that the proposed method achieves higher verification accuracy while compared with that of the original competitive coding scheme and several state-of-the-art methods, such as ordinal measure and RLOC. Considering both the computational complexity and the verification accuracy, competitive code with six orientations would be the optimal choice for palmprint recognition.     

Online finger-knuckle-print verification for personal authentication

Biometric based personal authentication is an effective method for automatically recognizing, with a high confidence, a person's identity. By observing that the texture pattern produced by bending the finger knuckle is highly distinctive, in this paper we present a new biometric authentication system using finger-knuckle-print (FKP) imaging. A specific data acquisition device is constructed to capture the FKP images, and then an efficient FKP recognition algorithm is presented to process the acquired data in real time. The local convex direction map of the FKP image is extracted based on which a local coordinate system is established to align the images and a region of interest is cropped for feature extraction. For matching two FKPs, a feature extraction scheme, which combines orientation and magnitude information extracted by Gabor filtering is proposed. An FKP database, which consists of 7920 images from 660 different fingers, is established to verify the efficacy of the proposed system and promising results are obtained. Compared with the other existing finger-back surface based biometric systems, the proposed FKP system achieves much higher recognition rate and it works in real time. It provides a practical solution to finger-back surface based biometric systems and has great potentials for commercial applications.     

Phase congruency induced local features for finger-knuckle-print recognition

Researchers have recently found that the finger-knuckle-print (FKP), which refers to the inherent skin patterns of the outer surface around the phalangeal joint of one’s finger, has high discriminability, making it an emerging promising biometric identifier. Effective feature extraction and matching plays a key role in such an FKP based personal authentication system. This paper studies image local features induced by the phase congruency model, which is supported by strong psychophysical and neurophysiological evidences, for FKP recognition. In the computation of phase congruency, the local orientation and the local phase can also be defined and extracted from a local image patch. These three local features are independent of each other and reflect different aspects of the image local information. We compute efficiently the three local features under the computation framework of phase congruency using a set of quadrature pair filters. We then propose to integrate these three local features by score-level fusion to improve the FKP recognition accuracy. Such kinds of local features can also be naturally combined with Fourier transform coefficients, which are global features. Experiments are performed on the PolyU FKP database to validate the proposed FKP recognition scheme.     

一种用于掌纹识别的线特征表示和匹配方法

作为一种较新的生物特征,掌纹可用来进行人的身份识别.在用于身份识别的诸多特征中,掌纹线,包括主线和皱褶,是最重要的特征之一.本文为掌纹识别提出一种有效的掌纹线特征的表示和匹配方法,该方法定义了一个矢量来表示一个掌纹上的线特征,该矢量称为线特征矢量(1ine feature vector,简称LFV).线特征矢量是用掌纹线上各点的梯度大小和方向来构造的.该矢量不但含有掌纹线的结构信息,而且还含有这些线的强度信息,因而,线特征矢量不但能区分具有不同线结构的掌纹,同时也能区分那些具有相似的线结构但各线强度分布不同的掌纹.在掌纹匹配阶段,用互相关系数来衡量不同线特征矢量的相似性.实验表明,LFV方法无论是在速度、精度,还是在存储量方面都能满足联机生物识别的要求.     

Texture-based palmprint retrieval using a layered search scheme for personal identification

This paper presents a new approach to palmprint retrieval for personal identification. Three key issues in image retrieval are considered: feature extraction, similarity measurement and fast search for the best match of the queried image in an image database. We propose a texture-based approach for palmprint feature representation. The concept of texture energy is introduced to define both global and local features of a palmprint, which are characterized with high convergence of inner-palm similarities and good dispersion of inter-palm discrimination. The searching is carried out in a layered fashion: the global features are first used to guide the fast selection of a small set of similar candidates from the database and then the local features are applied to determine the final output from the selected set of similar candidates. The experimental results illustrate the effectiveness of the proposed approach.     

掌纹识别研究进展综述

掌纹图像蕴含丰富特征,容易与手背静脉、指节纹及手形特征进行多模态融合,因此成为生物特征识别领域的热点.文中主要从掌纹的采集、感兴趣区域的检测、特征提取与匹配3方面介绍掌纹识别的基本流程.探讨基于不同特征融合的多模态识别策略.根据特征提取方法的不同,掌纹识别算法可分为基于手工设计的算法(如编码特征、结构特征、统计特征、子空间特征)和基于特征学习的算法(如机器学习和深度学习),文中对上述算法进行详细对比和分析.最后讨论未来掌纹识别面临的挑战和发展,特别是复杂场景下跨平台的掌纹识别系统.     

非接触式掌纹图像采集与图像增强技术研究

掌纹识别是生物特征识别领域的前沿课题,其中非接触式的掌纹识别技术因其具有用户体验性好、无卫生污染等特点,Et益成为相关研究领域的热点。但是非接触式的掌纹识别技术易受背景复杂、光照不足等不良因素的影响,给掌纹的图像采集与特征的提取匹配带来了困难。为了更好地解决这些问题,需要采用更为有效的图像增强技术。文中介绍了非接触式图像采集与预处理过程中图像增强技术的基本概念,对该技术实现方法进行了归类阐述和分析,探讨了该技术的发展趋势。     

Novel image fusion scheme based on dependency measure for robust multispectral palmprint recognition

Multispectral palmprint is considered as an effective biometric modality to accurately recognize a subject with high confidence. This paper presents a novel multispectral palmprint recognition system consisting of three functional blocks namely: (1) novel technique to extract Region of Interest (ROI) from the hand images acquired using a contact less sensor (2) novel image fusion scheme based on dependency measure (3) new scheme for feature extraction and classification. The proposed ROI extraction scheme is based on locating the valley regions between fingers irrespective of the hand pose. We then propose a novel image fusion scheme that combines information from different spectral bands using a Wavelet transform from various sub-bands. We then perform the statistical dependency analysis between these sub-bands to perform fusion either by selection or by weighted fusion. To effectively process the information from the fused image, we perform feature extraction using Log-Gabor transform whose feature dimension is reduced using Kernel Discriminant Analysis (KDA) before performing the classification by employing a Sparse Representation Classifier (SRC). Extensive experiments are carried out on a CASIA multispectral palmprint database that shows the strong superiority of our proposed fusion scheme when benchmarked with contemporary state-of-the-art image fusion schemes.     

Computational Intelligence-Based Biometric Technologies

Computational intelligence (CI) technologies are robust, can be successfully applied to complex problems, are efficiently adaptive, and usually have a parallel computational architecture. For those reasons they have been proved to be effective and efficient in bio-metric feature extraction and biometric matching tasks, sometimes used in combination with traditional methods. In this article, we briefly survey two kinds of major applications of CI in biometric technologies, CI-based feature extraction and CI-based biometric matching. Varieties of evolutionary computation and neural networks techniques have been successfully applied to biometric data representation and dimensionality reduction. CI-based methods, including neural network and fuzzy technologies, have also been extensively investigated for biometric matching. CI-based biometric technologies are powerful when used in the representation and recognition of incomplete biometric data, discriminative feature extraction, biometric matching, and online template updating, and promise to have an important role in the future development of biometric technologies     

多方向局部相位量化模式及纹理分类

梯度是图像的一种的特征，而同时考虑不同方向上的梯度信息是一种更加有效利用梯度的方式，因此提出多方向梯度的纹理局部相位量化模式算法。多方向梯度的纹理局部相位量化模式首先从不同方向提取图像的梯度特征，然后对每个方向上的梯度特征采用局部相位量化方法进行编码，各方向梯度采用相位量化编码后的特征连接成一个匹配特征向量。为了充分利用图像的梯度信息，还探讨了块模式的局部相位量化方法。两个纹理数据库和一个掌纹数据库上的实验充分表明，对图像各方向上的梯度信息进行局部相位量化编码是一种有效的纹理特征提取算法。