Parts: Structured Descriptions of Shape

A shape representation is presented that has been shown competent to accurately describe an extensive variety of natural forms (e g., people, mountains, clouds, trees), as well as man-made forms, in a succinct and natural manner. The ap preach taken in this representational system is to describe scene structure at a scale that is similar to our naive perceptual notion of “a part,’ by use of descriptions that reflect a possible formative history of the object, e.g., how the object might have been constructed from lumps of clay. For this representation to be useful it must be possible to recover such descriptions from image data; we show that the primitive elements of this representation may be recovered in an overconstrained and therefore potentially reliable manner.