Abstract
In this paper, a binary picture is partitioned into regions on the basis of geometrical properties. The definition of a region unit is induced from the basic geometrical property of regions. A region is defined as a union of the region units, and it is equivalently represented by its contours and covers, which are arranged in the form of indexed picture planes. This form is convenient for examining sequential as well as planer properties of regions. Furthermore, the local vertex is defined from the concept of digital lines, and a contour can be divided into line segments. A set of planar operators is given for those picture processings.
