Octree generation from silhouette views of an object

Octrees are used in many 3-D representation problems because they provide a compact data structure, allow rapid access to information, and implement efficient data manipulation algorithms. The initial acquisition of the 3-D information, however, is a common problem. This paper describes an algorithm to construct the octree representation of a 3-D object from silhouette images of the object. The images must be obtained from nine viewing directions corresponding to the three "face-on" and six "edge-on" views of an upright cube. The execution time is found to be linear in the number of nodes in the octree.