Patent ID: 6128414
Filing Date: 2000-10-03
Classification: G06K

Abstract:
In a symbol reading apparatus capable of storing an image of a data collection symbol, the stored image being comprised of a plurality of pixels and the symbol having a predetermined pattern of geometric shapes, a method of locating portions of the shapes within the stored image, the method comprising:sequentially identifying adjacent pixels along an edge of a shape within the stored image;performing at least one distortion compensating subroutine selected from a plurality of distortion compensating subroutines if an adjacent pixel cannot be located due to a distortion, wherein the at least one distortion compensating subrouting is selected from a first subroutine that crosses the shape to identify another edge of the shape, a second subroutine that jumps over the distortion, in a direction corresponding to an orientation of the edge, to identify an edge point on the edge following the distortion and without filling in the adjacent pixel, and a third subroutine that morphologically alters the distortion to cross the distortion and identify an edge point on the edge following the distortion;continuing sequentially identifying adjacent pixels following the distortion;producing a set of pixels that identify at least a portion of the shape based on the sequentially identifying, performing and continuing;determining if the set of pixels contains representations of one of several selected patterns of geometric portions for corresponding data collection symbology types, a first selected pattern corresponding to the predetermined pattern of geometric shape of the data collection symbol and which does not represent widths of a plurality of shapes as measured along an intersecting sampling path; andidentifying the data collection symbol in the stored image if the detected geometric portions correspond to the first selected pattern.