Instant 3Descatter

Imaging in scattering media such as fog and water is important but challenging. Images suffer from poor visibility due to backscattering and signal attenuation. Most prior methods for visibility improvement use active illumination scanners (structured and gated), which are slow and cumbersome. On the other hand, natural illumination is inapplicable to dark environments. The current paper counters these deficiencies. We study the formation of images under wide field (non-scanning) artificial illumination. We discovered some characteristics of backscattered light empirically. Based on these, the paper presents a visibility recovery approach which also yields a rough estimate of the 3D scene structure. The method is simple and requires compact hardware, using active wide field polarized illumination. Two images of the scene are instantly taken, with different states of a camera-mounted polarizer. A recovery algorithm then follows. We demonstrate the approach in underwater field experiments.