Recognition of polyhedra by a heterarchical program is presented. The program is based on the strategy of recognizing objects step by step, at each time making use of the previous results. At each stage, the most obvious and simple assumption is made and the assumption is tested. To find a line segment, a range of search is proposed. Once a line segment is found, more of the line is determined by tracking along it. Whenever a new fact is found, the program tries to reinterpret the scene taking the obtained information into consideration. Results of the experiment using an image dissector are satisfactory for scenes containing a few blocks and wedges. Some limitations of the present program and proposals for future development are described.
