Polarization mapping

Abstract

Photographers use the hardware of the camera (aperture, exposure time...), lens and filters as tools for artistic expressivity. This expressivity has often been enhanced by software, such as high dynamic range images have been edited in post-process with software tone mappers. In this paper, we propose a similar approach with polarization filters: we design a capture process that enables us to acquire a Stokes image (that encodes all the possible light polarization states) with a single camera, and we then offer a set of software tools that can apply any common polarization filter as a software post-process, delaying the choice of the adequate filter and enabling filters that can be mathematically modeled but are not available as hardware. Then, we devise and provide new algorithms that automatically select the optimal filter for specific goals, such as maximizing (or minimizing) brightness, contrast or saturation. We later show how such optimization filters can not only be applied to the whole image, but can also be at per-pixel level, obtaining new interesting effects. Such optimization can work at real time rates, fact that is illustrated with a brush based user editing interactive tool. The different types of filters are tested in a wide range of results.