Reading a boarding pass barcode is two problems, not one. The first is decoding the symbol: a printed pass carries PDF417, while Aztec Code, QR Code and Data Matrix appear on mobile passes and on printed passes from version 7 — and whichever symbol it is, it is often curved,...

The barcode on a boarding pass carries a payload defined by IATA Resolution 792 — an IATA Bar Coded Boarding Pass (BCBP). It is a fixed-order layout with mandatory and conditional sections, strictly sized fields, and two nested hexadecimal size fields that a reader has to follow to find where...