HueCode

HueCode is a proprietary bar code system, one of the few which use multiple colors to distinguish its elements (though it can also use grey-scale). It is covered by US patents 5,369,261 and 5,118,369. Codes are read with 400 x 400 DPI scanning.

Links

 * http://barcode-software.eu/symbology-huecode
 * http://www.barcode.ro/tutorials/barcodes/huecode.html