Barcode Reading and Accuracy

Barcodes use different sets of international standards to encode data as a series of white and black bars. The barcode symbology is also used to define the technical aspects of the coding of any particular type of barcode, such as the width of the bars, character sets, data encoding, and checksum specifications. The capabilities of each barcode symbology are often uniquely suited to the purpose or use it was designed for.

A barcode reader or scanner uses a photo sensor to convert the barcode to an electrical signal by measuring the width of the bars and spaces. It then translates the different patterns into characters that are readable by a computer. Every barcode begins with a special start character and ends with a stop character. Some barcodes may also contain a check sum character. This is an accuracy verification function performed by the reader's decoder, which generates a calculation and then compares the two values to make sure they match. If there is a mismatch, the scan is discarded and the reader throws out the data and re-scans.

Accuracy is one of the MOST convincing selling points for using barcode technology in laboratory applications. Studies indicate that even the best-trained data entry operator will make an error approximately every 300 key strokes. In comparison, even the simplest barcode has an error rate of not more than 1 error in 394,000 scans.