A method wherein images of different types of objects within a class are partitioned into region stacks. For each one of the stacks, the method: (a) applies a template to extract fragments having a predetermined size and one of a plurality of different spatial orientations, to generate extracted templates; (b) determines, from the extracted templates, a most frequent one thereof having only a first number of fragments with a common spatial orientations; (c) records the number of images having the determined most frequent extracted template; (d) repeats (b) and (c) with successively increasing number of fragments until the number of recoded images falls below a threshold; and (e) selects as a master extracted template the one of the most frequent templates having the largest recorded number of fragments. The master extracted templates for the stacks are combined into a map that is then compared with background images to remove extracted templates matching segment in the background.