Walrus use sea ice as a reproductive, migration and resting habitat. However, as sea ice melts and recedes, this marine mammal increasingly is threatened.
A University of Delaware research team, led by Chandra Kambhamettu, professor of computer and information sciences, has developed a novel camera system to map the surface topography of Arctic sea ice. The effort is part of a collaborative National Science Foundation project involving scientists at UD, the University of Virginia and the University of Alaska, Fairbanks, to assess walrus habitat.
Scott Sorensen, a doctoral student at UD, returned from a two-month expedition aboard the German research vessel Polarstern in October. He installed three cameras aboard Polarstern to continuously capture images of the sea ice during the expedition. He and fellow doctoral student Rohith Kumar designed the camera system in UD's Video/Imaging Modeling and Synthesis Laboratory (VIMS). The team is now using the raw data to reconstruct polar ice floes in 3-D. Dense reconstruction
Walrus gather in large herds of up to 10,000 animals in the heavy ice of the central Bering Sea in winter and migrate to the Chukchi Sea of Russia and Alaska in spring. During the summer, the sea ice melts and recedes into the Arctic Basin.
Sorensen explains that walruses move slowly on land, and if the ice floes are too large, they are at risk for predators such as polar bears. Too small and the ice will not support the walrus' weight.
"Without good metric data about ice floes and sea ice thickness, among other things, we can't really classify habitat," Sorensen says.
Ice, however, is very hard to reconstruct in 3-D because it is white and has no visual texture. Researchers typically rely on correspondences between pictures to recreate an image in 3-D, but determining what pixels correspond between two white images is nearly impossible.
"There is good data from satellites that use infrar
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University of Delaware