Patent ID: 6571006
Filing Date: 2003-05-27
Classification: G06K

Abstract:
A method for measuring an extent of a group of objects within a digital image, the method comprising:providing a reference signature of the group of objects representative of at least one arrangement of the objects relative to one another comprising: placing a window extending across at least a portion of the group of objects and having a projection axis substantially parallel to the extent of the group of objects at the reference position; detecting edges by projecting the part of the image within the window along the projection axis; and measuring a reference signature using the edges; placing a window extending across at least a portion of the group of objects and having a projection axis substantially parallel to the extent of the group of objects; measuring a measured signature at a plurality of positions of the window along a direction of the extent by projecting the part of the image within the window along the projection axis; comparing the reference signature to the measured signature at each of the plurality of positions; recording at least one window position at which the measured signature differs by a predetermined comparison criteria from the reference signature; and calculating the extent of the group of objects using the at least one window position.