QR Code Concepts

NI Vision 2019 for LabVIEW Help

Edition Date: March 2019

Part Number: 370281AG-01

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A QR Code is a matrix built on a square grid with a set of finder patterns located at three corners of the matrix. Finder patterns consist of alternating black and white square rings. The size of the matrix can range from a minimum size of 21 × 21 up to a maximum size of 177 × 177. Each cell of the matrix contains a single data cell. Matrix cells are square and represent a single binary 0 or 1.

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.

The following figure shows a example of a QR Code:


  1. Quiet Zone
  2. Finder Pattern
  3. Data Cell

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