1. A computer based method for man-machine interaction comprising the steps of: receiving a digital image of a target, the digital image comprising depth data associated with image pixels, the depth data corresponding to the distance to the camera; determining a location of a hand of the target within the pixels of the image based on the depth data associated with the pixels; and matching a candidate shape of the hand of the target captured in the digital image with a stored shape image from a plurality of shape images by comparing one or more of the plurality of stored shape images with the candidate shape.