Self-driving cars that recognize free space can better detect objects

The very fact that objects in your sight may obscure your view of things that lie further ahead is blindingly obvious to people. But Peiyun Hu, a Ph.D. student in CMU's Robotics Institute, said that's not how self-driving cars typically reason about objects around them. Rather, they use 3D data from lidar to represent objects as a point cloud and then try to match those point clouds to a library of 3D representations of objects. The problem, Hu said, is that the 3D data from the vehicle's lidar isn't really 3D -- the sensor can't see the occluded parts of an object, and current algorithms don't reason about such occlusions. "Perception systems need to know their unknowns," Hu observed.