Scanning beam system and method for reading information symbols

Abstract

A scanning system and method reads information symbols, such as optical mark recognition (“OMR”) symbols. Each OMR symbol typically includes a predetermined number of cells, with each cell containing a bar or a space. An object detector detects the presence of an object having an affixed OMR symbol and generates a trigger signal indicating an object has been detected. The object is typically moving past the scanning system and the trigger signal provides timing information for the system so the objects are scanned at the proper times. In response to the trigger signal, a scanner, such as a laser scanning device, scans and decodes the OMR symbol. The laser scanner includes an optical transmitter that generates a scanning laser beam that scans each OMR symbol when the symbol is within a scan window. An optical detector in the scanner is positioned to receive optical energy reflected from each OMR symbol responsive to the scanning laser beam. The optical detector generates a detection signal responsive to the received optical energy. A processing circuit is coupled to the optical transmitter and the optical receiver. The processing circuit processes the detection signal for a corresponding information symbol within the scan window to thereby read the information symbol.