A Framework for Representing and Reasoning about Three-Dimensional Objects for Vision

The capabilities for representing and reasoning about three-dimensional (3-D) objects are essential for knowledgebased, 3-D photointerpretation systems that combine domain knowledge with image processing, as demonstrated by 3-D Mosaic and ACRONYM. Three-dimensional representation of objects is necessary for many additional applications, such as robot navigation and 3-D change detection. Geometric reasoning is especially important because geometric relationships between object parts are a rich source of domain knowledge. A practical framework for geometric representation and reasoning must incorporate projections between a two-dimensional (2-D) image and a 3-D scene, shape and surface properties of objects, and geometric and topological relationships between objects. In addition, it should allow easy modification and extension of the system's domain knowledge and be flexible enough to organize its reasoning efficiently to take advantage of the current available knowledge.