|Vision Developoment Module 2019 Help|
|Vision Development Module 2020 Help|
Locating and decoding QR Codes requires a minimum cell size of 2.5 pixels. Locating and decoding PDF417 codes also requires a quiet zone of at least one cell width around the perimeter of the code. However, a larger quiet zone increases the likelihood of successful location. Each symbol character value is encoded in a unit called a code word consisting of 8 cells or one byte of data.
QR Codes have built in error checking and correction (ECC) using the standard Reed-Solomon scheme for error correction. The amount of error correction capability of each code is selectable during the printing process. In general, the QR Code can correct for anywhere from 7% to 30% of error depending upon the selection made at print time.