A basic understanding of barcode recognition algorithms can help you to make implementation choices that optimize your success. Basic 1-dimensional (1D) barcodes, such as Code 3 of 9, Code 128, and other codes that consist of bars of varying widths, are detected using quite different methods than the more complicated 2-dimensional (2D) barcodes such as PDF417, DataMatrix, and QR code. There are two basic steps for either: finding any barcode(s) on the page image, often called "location," and determining what information the barcode contains, or "decoding."

To locate 1D barcodes on a page, the software essentially scans the entire width, over the full height, of the document image, searching for black/white patterns of pixels that are typical of barcodes.