Abstract: A method to detect, process, and evaluate the quality of a succession of spaced bar code symbols. The symbols are disposed on a continuous substrate, moving past a scanner unit arranged to scan each symbol of the succession, one after the other. The method of the invention continuously scans the substrate to detect the entry of a bar code symbol into the field of view of the scanner unit. The presence of the bar code symbol in the scanner's field of view being established by a first valid decode of the symbol. Next, the first decoded scan and a plurality of subsequent decodable and non-decodable scans of the bar code symbol are processed to determine and store at least one evaluation attribute. The scanning and processing of the bar code continues until a predetermined number of consecutive non-decodable scans are processed, thereby indicating the absence of the bar code symbol from the field of view of the scanner and that the symbol has moved past the scanner.

Abstract: A method and apparatus to enable the high speed evaluation of the quality of a bar code indicia by processing a scan reflectance profile signal generated by a scanner unit. The scan reflectance profile signal is sampled by an analog-to-digital converter, with the sample values from the converter processed as they are produced in real-time to determine a highest positive peak sample value and a lowest negative peak sample value for each element of the bar code indicia. The lowest negative and highest positive peak sample values for each element being accessible for post-processing to determine at least one figure of merit indicative of the quality of the bar code indicia being evaluated. The samples produced by the a/d converter are processed as they are generated to filter and reduce the total collection of sample values stored and/or considered, while still providing the critical highest and lowest peak sample values for the scanned elements to enable high speed verification.