Browsing by Author "Hsieh, Sheng-Hsun"

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A Novel Anti-Spoofing Solution for Iris Recognition Toward Cosmetic Contact Lens Attack Using Spectral ICA Analysis
(2018-03-01)
Hsieh, Sheng-Hsun
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Li, Yung-Hui
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Wang, Wei
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Tien, Chung-Hao
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光電工程學系
In this study, we maneuvered a dual-band spectral imaging system to capture an iridal image from a cosmetic-contact-lens-wearing subject. By using the independent component analysis to separate individual spectral primitives, we successfully distinguished the natural iris texture from the cosmetic contact lens (CCL) pattern, and restored the genuine iris patterns from the CCL-polluted image. Based on a database containing 200 test image pairs from 20 CCL-wearing subjects as the proof of concept, the recognition accuracy (False Rejection Rate: FRR) was improved from FRR = 10.52% to FRR = 0.57% with the proposed ICA anti-spoofing scheme.
Biometric iris image acquisition system with wavefront coding
(2013)
Hsieh, Sheng-Hsun
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Yang, Hsi-Wen
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Huang, Shao-Hung
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Li, Yung-Hui
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Tien, Chung-Hao
Biometric signatures for identity recognition have been practiced for centuries. Basically, the personal attributes used for a biometric identification system can be classified into two areas: one is based on physiological attributes, such as DNA, facial features, retinal vasculature, fingerprint, hand geometry, iris texture and so on; the other scenario is dependent on the individual behavioral attributes, such as signature, keystroke, voice and gait style. Among these features, iris recognition is one of the most attractive approaches due to its nature of randomness, texture stability over a life time, high entropy density and non-invasive acquisition. While the performance of iris recognition on high quality image is well investigated, not too many studies addressed that how iris recognition performs subject to non-ideal image data, especially when the data is acquired in challenging conditions, such as long working distance, dynamical movement of subjects, uncontrolled illumination conditions and so on. There are three main contributions in this paper. Firstly, the optical system parameters, such as magnification and field of view, was optimally designed through the first-order optics. Secondly, the irradiance constraints was derived by optical conservation theorem. Through the relationship between the subject and the detector, we could estimate the limitation of working distance when the camera lens and CCD sensor were known. The working distance is set to 3m in our system with pupil diameter 86mm and CCD irradiance 0.3mW/cm(2). Finally, We employed a hybrid scheme combining eye tracking with pan and tilt system, wavefront coding technology, filter optimization and post signal recognition to implement a robust iris recognition system in dynamic operation. The blurred image was restored to ensure recognition accuracy over 3m working distance with 400mm focal length and aperture F/6.3 optics. The simulation result as well as experiment validates the proposed code apertured imaging system, where the imaging volume was 2.57 times extended over the traditional optics, while keeping sufficient recognition accuracy.
Extended depth of field system for long distance iris acquisition
(2012)
Chen, Yung-Lin
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Hsieh, Sheng-Hsun
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Hung, Kuo-En
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Yang, Shi-Wen
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Li, Yung-Hui
Using biometric signatures for identity recognition has been practiced for centuries. Recently, iris recognition system attracts much attention due to its high accuracy and high stability. The texture feature of iris provides a signature that is unique for each subject. Currently most commercial iris recognition systems acquire images in less than 50 cm, which is a serious constraint that needs to be broken if we want to use it for airport access or entrance that requires high turn-over rate. In order to capture the iris patterns from a distance, in this study, we developed a telephoto imaging system with image processing techniques. By using the cubic phase mask positioned front of the camera, the point spread function was kept constant over a wide range of defocus. With adequate decoding filter, the blurred image was restored, where the working distance between the subject and the camera can be achieved over 3m associated with 500mm focal length and aperture F/6.3. The simulation and experimental results validated the proposed scheme, where the depth of focus of iris camera was triply extended over the traditional optics, while keeping sufficient recognition accuracy.
Extending the Capture Volume of an Iris Recognition System Using Wavefront Coding and Super-Resolution
(2016-12)
Hsieh, Sheng-Hsun
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Li, Yung-Hui
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Tien, Chung-Hao
;
Chang, Chin-Chen
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光電工程學系
Iris recognition has gained increasing popularity over the last few decades; however, the stand-off distance in a conventional iris recognition system is too short, which limits its application. In this paper, we propose a novel hardware-software hybrid method to increase the stand-off distance in an iris recognition system. When designing the system hardware, we use an optimized wavefront coding technique to extend the depth of field. To compensate for the blurring of the image caused by wavefront coding, on the software side, the proposed system uses a local patch-based super-resolution method to restore the blurred image to its clear version. The collaborative effect of the new hardware design and software post-processing showed great potential in our experiment. The experimental results showed that such improvement cannot be achieved by using a hardware-or software-only design. The proposed system can increase the capture volume of a conventional iris recognition system by three times and maintain the system\'s high recognition rate.
Test of the Practicality and Feasibility of EDoF-Empowered Image Sensors for Long-Range Biometrics
(2016-12-01)
Hsieh, Sheng-Hsun
;
Li, Yung-Hui
;
Tien, Chung-Hao
;
光電工程學系
;
Department of Photonics
For many practical applications of image sensors, how to extend the depth-of-field (DoF) is an important research topic; if successfully implemented, it could be beneficial in various applications, from photography to biometrics. In this work, we want to examine the feasibility and practicability of a well-known "extended DoF" (EDoF) technique, or "wavefront coding," by building real-time long-range iris recognition and performing large-scale iris recognition. The key to the success of long-range iris recognition includes long DoF and image quality invariance toward various object distance, which is strict and harsh enough to test the practicality and feasibility of EDoF-empowered image sensors. Besides image sensor modification, we also explored the possibility of varying enrollment/testing pairs. With 512 iris images from 32 Asian people as the database, 400-mm focal length and F/6.3 optics over 3 m working distance, our results prove that a sophisticated coding design scheme plus homogeneous enrollment/testing setups can effectively overcome the blurring caused by phase modulation and omit Wiener-based restoration. In our experiments, which are based on 3328 iris images in total, the EDoF factor can achieve a result 3.71 times better than the original system without a loss of recognition accuracy.
The influence of phase mask position upon EDoF system
(2013)
Hsieh, Sheng-Hsun
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Lian, Zih-Hao
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Chang, Chong-Min
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Tien, Chung-Hao
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光電工程學系
Special types of pupil mask with the appropriate phase and transmission distribution can be used to modify the 3D point-spread function (PSF) in the desired way. Recently, many studies were addressed to extend the depth-of-field (EDoF) of an imaging system via cubic phase pupil engineering. The intermediate image is detected with a digital sensor and the final image formation is restored by post-process algorithms with the help of knowledge of the pupil mask. The EDoF system is operated based on an assumption that the phase mask should be positioned exactly in the pupil of the optical system. Unfortunately, in most practical cases, the exit pupil is not always available due to the complex layout of a compound lens set and results in a limited practical benefit of this type of arrangement. In this paper, we present the influence of the phase mask position upon PSF of an extended depth-of-field system. The characterizations of EDoF in different viewing angles are dissimilar if the phase mask is not placed in the perfect pupil plane. Such properties should be taken into consideration while designing an EDoF system. Finally, we will propose some potential candidate lenses made to alleviate such difficulty.