To be able to find/read/decode a QR barcode, it must meet the following criteria:
· The symbol to decode has to be standard.
· Around the QR barcode there must be at least one pixel width white space, called quiet zone. If not the decoding of the barcode is impossible. Sometimes a skewed QR barcode needs larger quiet zone size to properly decode. The quiet zone parameter can be adjusted by the user.
· The barcode cannot be extremely noisy and distorted. (Small slip of rows is compensated in an automatic preprocessing step.)