New technology allows to see clearly through murky water

Imaging clearly underwater is extremely challenging because the water and the particles in it tend to scatter light. But, because scattered light is partially polarized, imaging using a camera that is sensitive to polarization can be used to suppress scattered light in underwater images.

The new method even works in dense turbid water, which is so cloudy it is almost impossible to see through.

Researchers combined a traditional polarized imaging setup with a new algorithm that automatically finds the optimal parameters to suppress the scattering light. This not only significantly improves image contrast to achieve clear imaging but can be used without any prior knowledge of the imaging area and for images with or without background regions.

Researchers tested their new technique by acquiring images in turbid liquid mixtures in the laboratory. They started with a transparent tank filled with water and then blended in different amount of milk to mimic an underwater environment with different turbidity. They imaged various objects made from a variety of materials, such as wood, plastic and ceramic.

The new technology could be useful for searching for drowning victims, documenting submerged archaeological artifacts and monitoring underwater farms.

The principle used might be extendable to imaging through other scattering media such as fog, haze and smoke.