%0 Journal Article %J Discrete Applied Mathematics %D 2000 %T Centers of sets of pixels %A Khuller, Samir %A Rosenfeld,Azriel %A Wu,Angela %K Center %K Chessboard distance %K City block distance %K Intrinsic distance %K Simply connected set %X The center of a connected graph G is the set of nodes of G for which the maximum distance to any other node of G is as small as possible. If G is a simply connected set of lattice points (“pixels”) with graph structure defined by 4-neighbor adjacency, we show that the center of G is either a 2×2 square block, a diagonal staircase, or a (dotted) diagonal line with no gaps. %B Discrete Applied Mathematics %V 103 %P 297 - 306 %8 2000/07/15/ %@ 0166-218X %G eng %U http://www.sciencedirect.com/science/article/pii/S0166218X99002486 %N 1–3 %R 10.1016/S0166-218X(99)00248-6