19 October 2012 Extended depth of field system for long distance iris acquisition
Author Affiliations +
Proceedings Volume 8487, Novel Optical Systems Design and Optimization XV; 84870K (2012); doi: 10.1117/12.928192
Event: SPIE Optical Engineering + Applications, 2012, San Diego, California, United States
Abstract
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.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yuan-Lin Chen, Sheng-Hsun Hsieh, Kuo-En Hung, Shi-Wen Yang, Yung-Hui Li, Chung-Hao Tien, "Extended depth of field system for long distance iris acquisition", Proc. SPIE 8487, Novel Optical Systems Design and Optimization XV, 84870K (19 October 2012); doi: 10.1117/12.928192; https://doi.org/10.1117/12.928192
PROCEEDINGS
8 PAGES


SHARE
KEYWORDS
Iris recognition

Point spread functions

Imaging systems

Modulation transfer functions

Cameras

Wavefronts

Focus stacking

RELATED CONTENT


Back to Top