Chen W.-K.,Chien Hsin University of Science and Technology |
Lee J.-C.,Chinese Naval Academy |
Han W.-Y.,Chien Hsin University of Science and Technology |
Shih C.-K.,Chinese Naval Academy |
Chang K.-C.,Chung Cheng Institute of Technology
Information Sciences | Year: 2013
As the demand for information security increases, more attention is being paid to biometrics- based, automated personal identification. One of the most promising current biometric techniques is based on the human iris. This paper attempts to detect shape information from the iris by analyzing local intensity variations of an iris image. The methodology involves extraction of iris features using bidimensional empirical mode decomposition (BEMD) and fractal dimension. After the preprocessing procedure, the normalized effective iris image is decomposed into 2D intrinsic mode function (IMF) components at different spatial frequencies by bidimensional empirical mode decomposition. Then the texture features of each intrinsic mode function image are obtained via the differential box-counting method. To evaluate the efficacy of the proposed approach, three different similarity measures used in recognition are adopted. The experimental results using the CASIA and ICE iris databases show that the schema presented achieves promising results for iris recognition. Crown Copyright © 2012 Published by Elsevier Inc. All rights reserved.
Lee J.-C.,Chinese Naval Academy
Journal of Visual Communication and Image Representation | Year: 2015
With advancement of media editing software, even people who are not image processing experts can easily alter digital images. Various methods of digital image forgery exist, such as image splicing, copy-move forgery, and image retouching. The most common method of tampering with a digital image is copy-move forgery, in which a part of an image is duplicated and used to substitute another part of the same image at a different location. In this paper, we present an efficient and robust method to detect such artifacts. First, the tampered image is segmented into overlapping fixed-size blocks, and the Gabor filter is applied to each block. Thus, the image of Gabor magnitude represents each block. Secondly, statistical features are extracted from the histogram of orientated Gabor magnitude (HOGM) of overlapping blocks, and reduced features are generated for similarity measurement. Finally, feature vectors are sorted lexicographically, and duplicated image blocks are identified by finding similarity block pairs after suitable post-processing. To enhance the algorithm's robustness, a few parameters are proposed for removing the wrong similar blocks. Experiment results demonstrate the ability of the proposed method to detect multiple examples of copy-move forgery and precisely locate the duplicated regions, even when dealing with images distorted by slight rotation and scaling, JPEG compression, blurring, and brightness adjustment. © 2015 Elsevier Inc. All rights reserved.
Yen T.-H.,Chinese Naval Academy
Microfluidics and Nanofluidics | Year: 2014
This study performed the molecular dynamic simulations to investigate the boundary behavior of liquid water with entrapped gas bubbles over various hydrophilic roughened substrates. A "liquid-gas-vapor coexistence setup" was employed to maintain a constant thermodynamic state during individual equilibrium simulations and corresponding non-equilibrium Poiseuille flow cases. The two roughened substrates (Si(100) and graphite) adopted in this study present similar contact angles and slip length with gas-free fluid. By considering the effects of argon molecules at the interface, we demonstrated that the boundary slip behavior differed dramatically between these two rough wall channels. This divergence can be attributed to differences in the morphology of argon bubble at the interface due to discrepancies in the atomic arrangement and wall-fluid interaction energy. Furthermore, the density of gas at the interface had a significant impact on the effective slip length of the roughened graphite substrate, whereas shear rate γ̇ presented no noticeable influence. On the roughened Si(100) surface, the morphology of the argon bubbles exhibited far higher meniscus curvature and unstable properties under hydrodynamic effects. Thus, this substrate exhibited no slip to slight negative slip and no remarkable influence from either the density of gas at the interface or shear rate. In the present study, we demonstrate that the morphology and behavior of interfacial gas bubbles are influenced by the parameters of wall-fluid interaction as well as the atomic arrangement of the substrate. Our results related to nanochannel flow reveal that different surfaces, such as Si(100) and graphite, may possess similar intrinsic wettability; however, properties of the interfacial gas bubbles can lead to noticeable changes in interfacial characteristics resulting in various degrees of boundary slippage. © 2013 Springer-Verlag Berlin Heidelberg.
Lee J.-C.,Chinese Naval Academy
Advanced Science Letters | Year: 2012
Vein pattern recognition is one of the newest biometric techniques researched today. The palm vein authentication technology offers a high level of accuracy. One of the reliable and robust personal identification authentication approaches using palm vein patterns is presented in this paper. In our work, we consider the palm vein as a piece of texture and apply texture-based feature extraction techniques to palm vein authentication. A 2-D Gabor filter provides the optimized resolution in both the spatial and frequency domains, thus it is a basis for extracting local features in the palm vein recognition. In order to obtain effective pattern of palm vascular, we proposed an innovative and robust directional coding technique to encode the palm vein features in character set representation. The character set representation offers speedy template matching and enables more effective template storage and retrieval. The similarity of two palm vein images is measured by character matching. A total of 4140 palm vein images were collected form 207 persons to verify the validity of the proposed palm vein recognition approach. High accuracies have been obtained by the proposed method and the speed of this method is rapid enough for real-time palm vein recognition. Experimental results demonstrate that our proposed approach is feasible and effective in palm vein recognition. © 2012 American Scientific Publishers. All rights reserved.
Lee J.-C.,Chinese Naval Academy
Proceedings of the 14th IAPR International Conference on Machine Vision Applications, MVA 2015 | Year: 2015
Vein recognition, as an emerging biometric recognition approach, is becoming a very active topic in both research and practical applications. In our framework, the minutiae features is extracted from the dorsal hand vein patterns for recognition, which include end points and the distance between the two end points as measured along the boundary of the image. In addition, the end-points-tree (EP-tree) is proposed to accelerate the matching performance and evaluate the discriminating power of these end points for person verification purposes. We employed a total of 4,280 images of dorsal hand veins from 214 individuals in order to validate the proposed recognition method. In a comparison with three existing verification algorithms, the proposed method achieves the highest accuracy in the lowest matching time. © 2015 MVA organization.