Optical design of reflecting omnidirectional zoom optical system with peripheral half-field of view from 110° to 72° for day and night surveillance

Abstract

A reflecting omnidirectional zoom optical system (ROZOS) that is simultaneously operative in the visible-light (400 − 700 nm) and long-wave infrared (8 − 12 μm) ranges is designed for day and night unmanned surveillance and security. The half-field of view (HFOV) and F-number for the developed ROZOS are 40 − 110° and 2.4, respectively, enabling omnidirectional vision. In order to expand the concentrated image in the region of the central blocking area on the image sensor, we successfully established a ROZOS by two moving mirrors to play the role of the focator/variator and compensator, respectively. The zoom magnification and maximum lower HFOV vary from 1 to 1.24 and from 110° to 72° during zooming, respectively. During zooming, the modulation transfer function (MTF) exceed 0.30 at Nyquist frequencies of 34 lp/mm and 20 lp/mm, respectively, at all maximum lower HFOVs from 110° to 72° in the visible and long-wave infrared wavelength ranges. No performance issues are encountered as the ray aberration is very small over the entire zooming range. Tolerance analysis show that when the MTF is 0.3, the cumulative probability over the entire zooming range exceed 90 %.