Morphological Grain Operators for Binary Images

Connected morphological operators act on the level of the flat zones of an image, i.e., the connected regions where the grey-level is constant. For binary images, the flat zones are the foreground and background grains (connected components) of the image. A grain operator is a special kind of connected operator that uses only local information about grains: grain operators do not require information about neighbouring grains. This paper discusses connected morphological operators for binary images, with an emphasis on grain operators and grain filters.