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Space Occupancy Using Multiple Shadowimages

We address the problem of estimating 3-D space occupancy using video imagery in the context of mobile robotics. A stationary robot observes a cluttered scene from a single viewpoint, and a second robot illuminates the scene from a sequence of directions thus producing a sequence of grey-level images (see Fig. gif). Differences of successive images are used to compute a sequence of shadowimages. The problem is to compute free space and occupied space from these shadowimages. Solutions to this problem are known for the special case of terrain scenes. We generalize these solutions to non-terrain scenes by making two key observations. First, there is a subset constraint on the shadowimages of a non-terrain scene, which allows the visible surfaces of a non-terrain scene to be recovered by a terrain-based technique. Second, the remaining regions of the shadowimages provide a conservative estimate of the occupied space hidden by these visible surfaces.

M. Langer, G. Dudek, S.W. Zucker

A stationary robot observes a cluttered scene from a single viewpoint, and a second robot illuminates the scene from a sequence of directions. Space occupancy is computed from the sequence of shadowimages.



Thierry Baron
Mon Nov 13 10:43:02 EST 1995