Next Article in Journal
Design and Fabrication of Micro Hemispheric Shell Resonator with Annular Electrodes
Next Article in Special Issue
Target Detection over the Diurnal Cycle Using a Multispectral Infrared Sensor
Previous Article in Journal
Utilizing a Wristband Sensor to Measure the Stress Level for People with Dementia
Previous Article in Special Issue
Expanding the Detection of Traversable Area with RealSense for the Visually Impaired
Article Menu

Export Article

Open AccessArticle
Sensors 2016, 16(12), 1994;

Test of the Practicality and Feasibility of EDoF-Empowered Image Sensors for Long-Range Biometrics

Department of Photonics, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan
Department of Computer Science & Information Engineering, National Central University, No. 300 Zhongda Road, Zhongli District, Taoyuan 32001, Taiwan
Author to whom correspondence should be addressed.
Academic Editor: Gonzalo Pajares Martinsanz
Received: 28 September 2016 / Revised: 17 November 2016 / Accepted: 18 November 2016 / Published: 25 November 2016
(This article belongs to the Special Issue Imaging: Sensors and Technologies)
Full-Text   |   PDF [5099 KB, uploaded 25 November 2016]   |  


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. View Full-Text
Keywords: wavefront coding; extended depth of field; iris recognition; biometrics wavefront coding; extended depth of field; iris recognition; biometrics

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Hsieh, S.-H.; Li, Y.-H.; Tien, C.-H. Test of the Practicality and Feasibility of EDoF-Empowered Image Sensors for Long-Range Biometrics. Sensors 2016, 16, 1994.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Sensors EISSN 1424-8220 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top