minimizing an energy functional of said weighting functions and said auxiliary functions to derive k equations for said auxiliary functions, wherein said image is partitioned into 2k segments ??i based on a membership of each image point in each of said weighting functions according to ??i={x|??j=1,j???i 2 k (Ai???Aj)>0}, wherein x is a point in said image domain, and Ai and Aj are weighting funct