AN EFFICIENT WAVELET-BASED PALMPRINT VERIFICATION APPROACH

Author(s):  
S. M. PRASAD ◽  
V. K. GOVINDAN ◽  
P. S. SATHIDEVI

This paper proposes a wavelet-based palmprint verification approach which is efficient in terms of accuracy and speed. The prominent wavelet domain features such as subband energy distribution, histogram, and co-occurrence features fail to characterize the palmprints sufficiently due to coefficient perturbations caused by translational and/or rotational variations in palmprints. In this work, firstly, a novel approach, termed as adaptive tessellation of subbands, is proposed to effectively capture the spatially localized energy distribution based on the spread of principal lines. Secondly, a set of discriminating features, termed as high scale codes (HSCODEs), and a translation and rotation invariant matching technique are proposed. HSCODEs effectively characterize the palmprints by capturing the spatial patterns corresponding to the low frequency components. Energy features and selected HSCODEs are fused at score and decision levels. Particularly, score level fusion enhances the verification accuracy significantly. Effectiveness of the proposed approach is examined on PolyU-ONLINE-Palmprint-II (PolyU) database. The experimental results show an overall equal error rate (EER) of 0.22%, which is better than the existing wavelet-based palmprint recognition systems and comparable to the computationally complex state-of-the-art approaches. The speed of the approach is high as all the features are extracted from the same wavelet decomposition of palmprint. Further, it is shown that the proposed feature extraction technique can be extended for speech signals as well and such features can be fused with palmprint features for accuracy enhancement.

Author(s):  
Norah Abdullah Al-johani ◽  
Lamiaa A. Elrefaei

Advancements in biometrics have attained relatively high recognition rates. However, the need for a biometric system that is reliable, robust, and convenient remains. Systems that use palmprints (PP) for verification have a number of benefits including stable line features, reduced distortion and simple self-positioning. Dorsal hand veins (DHVs) are distinctive for every person, such that even identical twins have different DHVs. DHVs appear to maintain stability over time. In the past, different features algorithms were used to implement palmprint (PP) and dorsal hand vein (DHV) systems. Previous systems relied on handcrafted algorithms. The advancements of deep learning (DL) in the features learned by the convolutional neural network (CNN) has led to its application in PP and DHV recognition systems. In this article, a multimodal biometric system based on PP and DHV using (VGG16, VGG19 and AlexNet) CNN models is proposed. The proposed system is uses two approaches: feature level fusion (FLF) and Score level fusion (SLF). In the first approach, the features from PP and DHV are extracted with CNN models. These extracted features are then fused using serial or parallel fusion and used to train error-correcting output codes (ECOC) with a support vector machine (SVM) for classification. In the second approach, the fusion at score level is done with sum, max, and product methods by applying two strategies: Transfer learning that uses CNN models for features extraction and classification for PP and DHV, then score level fusion. For the second strategy, features are extracted with CNN models for PP and DHV and used to train ECOC with SVM for classification, then score level fusion. The system was tested using two DHV databases and one PP database. The multimodal system is tested two times by repeating PP database for each DHV database. The system achieved very high accuracy rate.


Author(s):  
Galina Rozhkova ◽  
Dmitry Lebedev ◽  
Maria Gracheva ◽  
Svetlana Rychkova

Abstract To date, there are no generally accepted optotypes for monitoring visual acuity. All common optotypes are not completely suitable for some reasons. The tasks requiring visual monitoring - investigation of visual development, early diagnostics, assessment of treatment - impose heavy demands on the test stimuli. They must be: (1) suitable for patients of any age; (2) convenient for repeatable examinations; and (3) accurate enough for revealing the smallest physiologically significant changes of visual acuity. From theoretical consideration, one could conclude that the optotypes for monitoring visual acuity should be designed for measuring visual resolution but not recognition, unlike most popular optotypes. The best optotypes for visual resolution are gratinglike stimuli whose recognition could only be based on the high frequency part of the Fourier spectrum around the characteristic frequency (not on the low-frequency components). On the basis of theoretical analysis we elaborated modified 3-bar optotypes, which minimise the possibility of using low-frequency cues for stimulus recognition. In this paper we present the results of theoretical and experimental comparison of these optotypes with the two widely used ones: tumbling-E and standard 3-bar targets. According to the data obtained, our modified optotypes seem to be better than other investigated ones for monitoring visual acuity.


Optik ◽  
2013 ◽  
Vol 124 (18) ◽  
pp. 3340-3344 ◽  
Author(s):  
Shuwen Zhang ◽  
Xuxin Gu

Author(s):  
Esraa Alqaralleh ◽  
Önsen Toygar

This paper proposes a 2D ear recognition approach that is based on the fusion of ear and tragus using score-level fusion strategy. An attempt to overcome the effect of partial occlusion, pose variation and weak illumination challenges is done since the accuracy of ear recognition may be reduced if one or more of these challenges are available. In this study, the effect of the aforementioned challenges is estimated separately, and many samples of ear that are affected by two different challenges concurrently are also considered. The tragus is used as a biometric trait because it is often free from occlusion; it also provides discriminative features even in different poses and illuminations. The features are extracted using local binary patterns and the evaluation has been done on three datasets of USTB database. It has been observed that the fusion of ear and tragus can improve the recognition performance compared to the unimodal systems. Experimental results show that the proposed method enhances the recognition rates by fusion of parts that are nonoccluded with tragus in the cases of partial occlusion, pose variation and weak illumination. It is observed that the proposed method performs better than feature-level fusion methods and most of the state-of-the-art ear recognition systems.


Author(s):  
G. Y. Fan ◽  
J. M. Cowley

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.


Author(s):  
В. М. Мойсишин ◽  
M. V. Lyskanych ◽  
R. A. Zhovniruk ◽  
Ye. P. Majkovych

The purpose of the proposed article is to establish the causes of oscillations of drilling tool and the basic laws of the distribution of the total energy of the process of changing the axial dynamic force over frequencies of spectrum. Variable factors during experiments on the classical plan were the rigidity of drilling tool and the hardness of the rock. According to the results of research, the main power of the process of change of axial dynamic force during drilling of three roller cone bits is in the frequency range 0-32 Hz in which three harmonic frequency components are allocated which correspond to the theoretical values of low-frequency and gear oscillations of the chisel and proper oscillations of the bit. The experimental values of frequencies of harmonic components of energy and normalized spectrum as well as the magnitude of the dispersion of the axial dynamic force and its normalized values at these frequencies are presented. It has been found that with decreasing rigidity of the drilling tool maximum energy of axial dynamic force moves from the low-frequency oscillation region to the tooth oscillation area, intensifying the process of rock destruction and, at the same time, protecting the tool from the harmful effects of the vibrations of the bit. Reducing the rigidity of the drilling tool protects the bit from the harmful effects of the vibrations generated by the stand. The energy reductions in these fluctuations range from 47 to 77%.


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