Seeing Empty Space in an Unknown Environment without Silhouettes

Summary

We show that a map of empty space around objects near a mobile camera in an unknown environment can be obtained from a naive light field model of image data. We observe that, between the nearest objects, cells with different light in different directions correspond to empty space. We describe experiments with a robot in an environment with black objects and white objects seen against a black and white background. As there are no absolute silhouettes in this environment, ordinary silhouette methods cannot be used. We demonstrate that the robot is able, in real-time, to find and pass through a gap in a row of objects or stop if no gap is wide enough.