The 3D data acquisition method.

A: Examples of a depth image (top left) captured by 1 depth camera, a corresponding color image (top right), and a 3D point cloud extracted from the depth image (bottom). B: The recording setup. Rats in the central recording chamber were captured by 4 depth cameras from different viewpoints. C: An example of a 3D hull of a rat that was reconstructed by merging the point clouds that were captured by the 4 depth cameras. Dotted lines indicate the silhouettes of a captured rat (which is rearing). The surrounding pictures show point clouds that were captured by the 4 depth cameras, with arrows indicating the viewing directions of the cameras; and the central picture shows a merged point cloud. Different point colors represent different cameras used to capture the points and the white line attached to the points represents the surface normal at the points.