Measuring Waves Without Getting Wet

A remote-controlled stereo vision system now under development could revolutionize the science of watching how, where and when waves tear up coastlines, say researchers.

Storm swells that pound at coastlines -- thrilling surfers and worrying coastal engineers -- have always been hard to monitor. Wave-measuring buoys don't work well in the surf zone. Like other methods, they only provide data for one small point of surf rather than the beach-wide, broader-scale surf event.

Radar systems, for their part, provide nice wave speed information -- like a police officer's radar gun -- but are not very good at measuring wave heights.

By linking two visible-light camera together, however, and processing the images in a way similar to how the human brain does with the vision of two eyes, loads more wave data can be collected without even getting a toe wet. The potential applications of the technique are growing more important as climate change is growing larger surf that threatens more coastlines worldwide.

"It's like two eyes," explained researcher David Hill of Oregon State University. "It doesn't just see the waves and see them moving, but how high they are."

Hill worked with Dutch researchers on a stereo vision system that is beginning to yield specific wave height information for a swath of surf that is more on the scale of a recreational beach. Their research results will be published in the March 2011 issue of the journal Coastal Engineering.

"As you get closer to shore, there's a lot more variability" caused by shoaling waters refractions of waves and other shoreline effects, Hill explained to Discovery News. There have been other attempts to use stereo vision to measure waves, he said, but not on a realistic and useful area of surf.

Their latest experiment involved two off-the-shelf digital cameras on a pier on the Dutch coast. The data was processed by an ordinary desktop computer.