Distributed focus and digital zoom

Abstract

We explore integrated microcamera focus systems for array cameras. Array cameras enable wide field of view 90° to 360° high resolution (10–100 μrad) imaging with small exit apertures (≈10 mm). Small exit apertures enable compact focus mechanisms with fast actuators. We show that a common mechanism supports ≈f/2.5 camera modules with focal lengths ranging from 25 to 60 mm. Designs for each focal length include a fixed objective lens group and an adjustable back focus group. Increasing the focal power of the front focal group enables the travel range to accommodate long focal length systems. We present design examples for both discrete and multiscale array camera systems.

Lens sensitivity to aberration: scaling rules

“…The overall goal is to select a microcamera aperture that matches desired instantaneous field of view targets while selecting a microcamera field of view that minimizes system cost per pixel. Over a wide range of resolution targets, this goal can be achieved using a common sensor size with microcamera field of view decreasing linearly as a function of the instantaneous field of view 4 . Although this approach works well from a design perspective, one may reasonably wonder whether or not manufacturing tolerances must be tightened as focal length increases and how lens sensitivities scale.…”

“…Over a wide range of resolution targets, this goal can be achieved using a common sensor size with microcamera field of view decreasing linearly as a function of the instantaneous field of view. 4 Although this approach works well from a design perspective, one may reasonably wonder whether or not manufacturing tolerances must be tightened as focal length increases and how lens sensitivities scale.…”