Researchers devise sonar-guided system to help underwater vehicles see through murky water

When remotely operated vehicles settle on the seafloor or dig through a sand bed, they can kick up clouds of sediment that onboard cameras struggle to see through. Often, the only thing to do is wait until the dust settles, the report said. The new method instead uses sonar to quickly map the surroundings because sonar works equally well in cloudy and clear water, even though it does not provide detailed resolution.

That rough map allows a vehicle to safely get close enough to specific objects for its cameras to visualize them more carefully. To speed up the processing so the mapping can be done in real time, Phung and Camilli combined the sonar technology with an image-matching algorithm developed by researchers in France that quickly estimates the relative depth of each pixel in a 2D scene.

Camilli compared the technique to moving through a dark china shop to find a specific coffee mug without knocking things over. "This would allow you to do that," he said. He and Phung said applications could include scientific exploration, underwater construction and maintenance, and handling of unexploded undersea mines.