Improving Underwater Imaging with Ocean Optics Research
NAVAL RESEARCH LAB WASHINGTON DC
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Underwater vision is vital to many Navy applications involving mine detection, diver visibility, and search and rescue. The ability to see better and farther has always been a central goal of underwater imaging projects. Unlike in the atmosphere, where visibility can be on the order of miles, the visual range in the underwater environment is rather limited, at best on the order of tens of meters, even in the clearest waters. This is the result of combined attenuation effects from both absorption, where photons disappear into water molecules, phytoplankton cells, and detritus, and scattering, where photons bounce away from the original path into different traveling directions. It is mostly the effects of scattering by water and particulates that make the water look dirty or less transparent, resulting in a blurred image recorded by cameras. Although traditional image enhancement techniques can be applied to imagery obtained from underwater environments, their effectiveness is considerably limited because they do not take into account any knowledge of the optical properties of the medium or the processes that lead to the degraded images. Our efforts aim to find ways to incorporate the knowledge of ocean optics to automatically enhance and restore such blurred images from underwater imaging systems, and in turn, to be able to estimate environmental optical properties via through-the-sensor techniques.
- Physical and Dynamic Oceanography