1. An automated method for estimating motion of an image segment, the method comprising: segmenting an image frame into constituent image segments, wherein the segments are irregularly shaped; estimating motion vectors of blocks of pixels in the image frame, wherein the blocks are rectangular in shape; determining the blocks which overlap a segment; obtaining candidate motion vectors belonging to the segment from the motion vectors of the blocks which overlap the segment; and selecting a motion vector for the segment from amongst the candidate motion vectors, wherein the method is performed by a microprocessor executing computer-readable code.