1. A method for segmentation of an image, comprising the steps of: acquiring the image employing an image acquisition apparatus with a shallow depth of field, the focus of the image apparatus being on one or more foreground objects in the image; clustering pixels from the one or more foreground objects in the acquired image into one or more segments; determining one or more unstable segments changing by more than a predetermined threshold from one or more prior images; determining depth only for one or more of the one or more unstable segments that have changed by more than the predetermined threshold; and updating a depth map by updating only the segments having their depth determined.