Following boundaries of discrete binary objects in space

Abstract

Two algorithms for finding and following the boundaries of a set of discrete objects in n-dimensional space are described; they are compared in three dimensions. In three dimensions, the new method is found to be about three times as fast as the straightforward approach. It operates on the boundary (surface) of the object rather than the whole object (i.e. the set of volume elements). The boundary, in turn, is found very rapidly using logical operations on the bit patterns by which the discrete object is stored. Applications to three dimensional shape recognition and display problems are discussed.