Hi, are your shapes always separated from the backgrund that easily ( like black on white, or like shape below, background above teh bitmap.s mean level or some other trivial way to determine whether pixel belongs to a shape or background.) Also are the shaes separated from each other, no touching and overlap, It this is the case s imple flood fill algortihm would solve this (keeping trask of min max x/y coordinates, I guess the bounding box is axis aligned). For grater speed and lower stack usae a line scan flood fill is better , 4 or 8 connectivity, I inded use such thignfor some object detecion on job programs .. only a little bit bad think i I am less C# expariaenced, but Iguess I can do this if I have some time to se some bitmap loading and such auxilary things...