All-in-Focus Iris Camera With a Great Capture Volume

TL;DR

This paper introduces an all-in-focus iris imaging system that uses focus-tunable lenses and 2D steering mirrors to significantly extend capture volume and depth of field without mechanical motion, enabling real-time multi-person iris recognition.

Contribution

The study presents a novel iris camera with focus-tunable lenses and active beam steering, greatly increasing depth of field and field of view for biometric applications.

Findings

Depth of field extended up to 3.9 meters, 37.5 times greater than conventional lenses.

Capable of real-time multi-person iris refocusing using dynamic focal stacks.

Demonstrates potential for continuous iris recognition of moving subjects.

Abstract

Imaging volume of an iris recognition system has been restricting the throughput and cooperation convenience in biometric applications. Numerous improvement trials are still impractical to supersede the dominant fixed-focus lens in stand-off iris recognition due to incremental performance increase and complicated optical design. In this study, we develop a novel all-in-focus iris imaging system using a focus-tunable lens and a 2D steering mirror to greatly extend capture volume by spatiotemporal multiplexing method. Our iris imaging depth of field extension system requires no mechanical motion and is capable to adjust the focal plane at extremely high speed. In addition, the motorized reflection mirror adaptively steers the light beam to extend the horizontal and vertical field of views in an active manner. The proposed all-in-focus iris camera increases the depth of field up to 3.9 m which is a factor of 37.5 compared with conventional long focal lens. We also experimentally demonstrate the capability of this 3D light beam steering imaging system in real-time multi-person iris refocusing using dynamic focal stacks and the potential of continuous iris recognition for moving participants.