THE SPACE ENVELOPE - A REPRESENTATION FOR 3D SCENES

This work introduces the space envelope, a shape model based upon a bo undary description. Instead of modeling a single object (OC solid), a space envelope encloses a volume of empty space, The advantage is that in any given view, there may be any number of objects, this number be ing difficult to determine from pixel-data alone, However, there is al ways one, and only one, volume of visible empty space. Once a model ha s been constructed defining the space envelope, higher-order operation s may be applied to reason about the scene's content. For instance, su rface geometries and topology could yield insight into the number of v isible objects. The enclosed empty volume may also be used for vision- based navigation (known free-space), while the surfaces are used for v iew correspondences. Algorithms to automatically construct a planar bo undary representation (b-rep) space envelope from a range image are pr esented. Results for testing the algorithms on over 400 images from fo ur different range cameras are presented. (C) 1998 Academic Press.