A system for processing output signals of an electro-optical scanner adapted for reading a bar code indicia having parts of different light reflectivity and non bar code indicia adjacent the bar code on an article being scanned comprises a decoder for decoding content of signals input thereto...http://www.google.com.au/patents/US5821520?utm_source=gb-gplus-sharePatent US5821520 - Bar code scanning system with the pre-decoding signal processing and method for bar code candidate selection for decoding 
