The Boundary Count of Digital Pictures
J. C. Alexander, Alvin Isaac Thaler · Journal of the ACM · 1971
Cell complexes are associated with digital pictures in a natural way.The resulting topological concepts, e.g.components and fundamental group, agree with the standard usages.The notion of a boundary curve of a digital picture is defined, and with it, for any element a in the picture, two boundary counts, which are essentially (1) the number of times some bound° ary curve passes through ,~, and (2) the number of such curves.These concepts capture most vf the topology of the picture, and also solve the problem of finding the "removable" elements of the picture.