Synthetic Aperture Focusing Using Dense Camera Arrays

Abstract

Synthetic aperture focusing consists of warping and adding together the images in a 4D light field so that objects lying on a specified surface are aligned and thus in focus, while objects lying off this surface are misaligned and hence blurred. This provides the ability to see through partial occluders such as foliage and crowds, making it a potentially powerful tool for surveillance. In this paper, we describe the image warps required for focusing on any given focal plane, for cameras in general position without having to perform a complete metric calibration. We show that when the cameras lie on a plane, it is possible to vary the focus through families of frontoparallel and tilted focal planes by shifting the images after an initial recitification. Being able to vary the focus by simply shifting and adding images is relatively simple to implement in hardware and facilitates a real-time implementation. We demonstrate this using an array of 30 video-resolution cameras; initial homographies and shifts are performed on per-camera FPGAs, and additions and a final warp are performed on 3 PCs.