Patent ID: 7546950
Filing Date: 2009-06-16
Classification: G06K

Abstract:
1. A method of extracting a bitstream from a machine-readable symbol in an image, the symbol comprising three finder patterns adjacent respective corners of the symbol and generally defining the corners of a right-angled triangle, the method comprising: using one or more computer processing units to perform the following: identifying the finder patterns in the symbol; orienting the symbol using the finder patterns, the orienting comprising determining which of the three finder patterns is positioned at the corner of the triangle opposite its hypotenuse (“top left finder pattern” ), and labeling the remaining two finder patterns based on the relative distance between the remaining two finder patterns that would result if one of the remaining two finder patterns were rotated about the top left finder pattern less than 180 degrees, wherein the labeling comprises: on the basis of the orienting, delineating the symbol, wherein the delineating comprises: mapping a decoding grid to the delineated symbol; and extracting bit values from the mapped symbol.