Utilizing Optical Aberrations for Extended-Depth-of-Field Panoramas

Abstract

Optical aberrations in off-the-shelf photographic lenses are commonly treated as unwanted artifacts that degrade image quality. In this paper we argue that such aberrations can be useful, as they often produce point-spread functions (PSFs) that have greater frequency-preserving abilities in the presence of defocus compared to an ideal thin lens. Specifically, aberrated and defocused PSFs often contain sharp, edge-like structures that vary with depth and image position, and become increasingly anisotropic away from the image center. In such cases, defocus blur varies spatially and preserves high spatial frequencies in some directions but not others. Here we take advantage of this fact to create extended-depth-of-field panoramas from overlapping photos taken with off-the-shelf lenses and a wide aperture. We achieve this by first measuring the lens PSF through a one-time calibration and then using multi-image deconvolution to restore anisotropic blur in areas of image overlap. Our results suggest that common lenses may preserve frequencies well enough to allow extended-depth-of-field panoramic photography with large apertures, resulting in potentially much shorter exposures.