Abstract: Methods for efficiently retrieving information from an image of a symbol are described. Symbols are described that contain detection patterns that facilitate the determination of location, alignment, size and orientation of the symbol in an image. Detection patterns are described that possess geometric shapes susceptible to efficient decoding using probabilistic detection algorithms. Detection patterns are described that are provided in colors, shapes and sizes different from the color, shape and sizes of modules carrying information in the symbol. Methods are described for identifying the location and size of detection patterns in images of the symbol and for locating modules in the symbol to facilitate extraction of information carried by the modules.

Abstract: Methods for efficiently retrieving information from an image of a symbol are described. Symbols are described that contain detection patterns that facilitate the determination of location, alignment, size and orientation of the symbol in an image. Detection patterns are described that possess geometric shapes susceptible to efficient decoding using probabilistic detection algorithms. Detection patterns are described that are provided in colors, shapes and sizes different from the color, shape and sizes of modules carrying information in the symbol. Methods are described for identifying the location and size of detection patterns in images of the symbol and for locating modules in the symbol to facilitate extraction of information carried by the modules.