Patent ID: 7581171
Filing Date: 2009-08-25
Classification: G06F

Abstract:
1. A method of labeling a document image containing positionally encoded maze patterns for computationally efficient decoding, the method comprising: obtaining the document image; analyzing the document image to determine a number of position encoding bits that can be extracted from the document image, the analyzing including: dividing the document image into blocks having substantially a same size as maze pattern cells; determining whether the blocks are occluded by document content; counting, for each pixel in the document image, a number of completely visible blocks in a neighboring window with the pixel being as a center of the window; and labeling the pixel based on the number; performing a thresholding algorithm on the document image to determine if the document image is of a type selected from at least: a first type containing sufficient amount of visible positionally encoded maze patterns for a computationally efficient algorithm to decode the document image, and a second type containing document content that occludes at least a portion of the positionally encoded maze patterns, wherein the occlusion results in insufficient amount of maze patterns being visible for the computationally efficient algorithm to decode the document image; labeling the document image with the type based on the number of position encoding bits; and performing a search algorithm on the document image when an insufficient amount of maze patterns are visible.