Abstract: A technique for reading a bar code representative of message information is stored electronically in bit-map form. The bit map is obtained by optically scanning a document carrying non-bar code information also to convert pixel information into bit information. A row is identified in the bit map which is the most likely one to pass through an area in the bit map containing bar code information. The data stored in the bit map is compared with assigned data corresponding to designated bar code components. Once such a row is identified, processing of rows above and below it in the bit map reveals whether rows more likely to agree with the coded message information can be found. Initially, a fast processing mode is selected involving processing of only a few rows to maximize processing speed in case acceptable data can be found. If acceptable bar code data is not found, then the processing is switched into a slow processing mode which involves processing of a greater number of rows.