Color processing for bar code symbol compaction

Abstract

A method and apparatus for increasing the information density of a bar code symbol by generating multiple constituent bar code symbols, wherein each one is formed in a different color selected from a group of various primary colors, and overlaying each differently colored symbol on top of each other, thus forming an aggregate bar code symbol of various colors. In areas where the differently colored bars overlap each other, colors distinct from those in the original group of colors are formed. The aggregate bar code symbol is scanned by a solid state imaging device, and the scanned image is resolved by image processing techniques into the three constituent bar code symbols of the various colors. Each bar code symbol is then individually processed and decoded in accordance with the particular symbology used to encode the constituent bar code symbols. As a result of the present invention, multiple bar code symbols are printed in the space normally required by one bar code symbol, and each constituent symbol is separated by color resolution and decoded to form the original data. Thus, the information density of the bar code system is increased without the need for a new symbology. In addition, a single bar code symbol may be divided into multiple portions of substantially the same size and printed substantially over each other in different colors, thus producing a single compacted bar code symbol with increased information density. The compacted bar code symbol may be recovered by scanning and resolving the symbol back into its constituent portions, concatenating the portions together, and decoding the resulting bar code symbol in accordance with standard techniques.