Patent ID: 7549585

Claim:
A bar code scanner comprising: an optical assembly for generating a scan pattern and producing a scan signal based on reflections of the scan pattern from a bar code; a rules table where rules and criteria used to manage conditions affecting the reliability of bar code detection and decoding are stored; and a processor for processing the scan signal to decode a bar code based on information from a scan signal generated by a reflection of a scan line intersecting a bar code, the processor estimating a position of the bar code based on conditions prevailing at a time that the bar code is detected and to use position estimates to distinguish between consecutive scans of separate but identical bar codes and double scans of the same bar code, the processor being further operative to use rules and criteria from the rules table to recognize lapses of time in which no position estimate can be made and to evaluate position estimates and lapses of time in order to identify sets of scans that cannot be reliably identified as double scans or scans of separate but identical bar codes.