Foveated imaging can deliver two different resolutions on a single focal plane, which might inexpensively allow more
capability for military systems. The following design study results provide starting examples, lessons learned, and
helpful setup equations and pointers to aid the lens designer in any foveated lens design effort.
Our goal is to put robust sensor in a small package with no moving parts, but still be able to perform some of the
functions of a sensor in a moving gimbal. All of the elegant solutions are out (for various reasons). This study is an
attempt to see if lens designs can solve this problem and realize some gains in performance versus cost for airborne
sensors. We determined a series of design concepts to simultaneously deliver wide field of view and high foveal
resolution without scanning or gimbals.
Separate sensors for each field of view are easy and relatively inexpensive, but lead to bulky detectors and electronics.
Folding and beam-combining of separate optical channels reduces sensor footprint, but induces image inversions and
reduced transmission. Entirely common optics provide good resolution, but cannot provide a significant magnification
increase in the foveal region. Offsetting the foveal region from the wide field center may not be physically realizable, but
may be required for some applications.
The design study revealed good general guidance for foveated optics designs with a cold stop. Key lessons learned
involve managing distortion, telecentric imagers, matching image inversions and numerical apertures between channels,
reimaging lenses, and creating clean resolution zone splits near internal focal planes.