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Proceedings Paper

Optical design of a dual-channel two-focal-length system by utilizing azimuth property of PAL structure
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Paper Abstract

An approach to design a dual-channel two-focal-length lens based on the panoramic annular lens (PAL) structure is presented in this paper. The method of establishing the second channel to eliminate the blind area has been explored in some documents, and mostly it is achieved by utilizing the front surface of the PAL block. But in this paper, we modified the PAL block and divided it into two channels according to their different azimuth direction. These two channels have different focal lengths. Thus, by rotating the system around its axis, optical step-zoom effect can be obtained. Finally, a dual-channel system with a radial zoom ratio of 3× is designed, of which the wide-angle channel has a field-of-view (FOV) of 60° (radial) ×60° (azimuthal) and the long focal length channel has a FOV of 20° (radial)×20° (azimuthal). These two channels share the same stop surface, relay lens, and the image sensor. And a thin glass plate with diffractive structure is placed before the image plane to further correct aberration and obtain a common back focal length for the two channels. This system may have applications in many fields, such as surveillance, robot vision, and foveal imaging.

Paper Details

Date Published: 31 October 2016
PDF: 6 pages
Proc. SPIE 10021, Optical Design and Testing VII, 100211V (31 October 2016); doi: 10.1117/12.2246996
Show Author Affiliations
Chen Xu, Beijing Institute of Technology (China)
Dewen Cheng, Beijing Institute of Technology (China)
Yongtian Wang, Beijing Institute of Technology (China)

Published in SPIE Proceedings Vol. 10021:
Optical Design and Testing VII
Yongtian Wang; Tina E. Kidger; Kimio Tatsuno, Editor(s)

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