The Incremental Rigidity Scheme for Recovering Structure from Motion: Position versus Velocity Based Formulations
MASSACHUSETTS INST OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB
Pagination or Media Count:
Perceptual studies suggest that the visual system uses the rigidity assumption to recover three dimensional structure from motion. Ullman 1984 recently proposed a computational scheme, the incremental rigidity scheme, which uses the rigidity assumption to recover the structure of rigid and nonrigid objects in motion. The scheme assumes the input to be discrete positions of elements in motion, under orthographic projection. We present formulations of Ullmans method that use velocity information and perspective projection in the recovery of structure. Theoretical and computer analyses show that he velocity based formulations provide a rough estimate of structure quickly, but are not robust over an extended time period. The stable long term recovery of structure requires disparate views of moving objects. Our analysis raises interesting questions regarding the recovery of structure from motion in the human visual system. Keywords Space perception.
- Anatomy and Physiology