Scan

Scanning is the act of reading a QR code with a camera or laser sensor to recover its stored data. All QR code usage begins with a scan. When a smartphone camera is pointed at a QR code, image processing algorithms detect the finder patterns (three corner squares), identify the code region, and decode the module pattern, typically completing in under 0.1 seconds.

Four factors determine scan success: contrast (black on white is most reliable), distance (3-10 times the code's side length), quiet zone (at least 4 modules of margin), and print quality (ink bleeding, paper creases, and glossy reflections all reduce accuracy).

In high-volume scenarios like warehouse logistics or event entry management with hundreds of daily scans, dedicated barcode readers outperform smartphones with faster, more consistent scanning using laser or CCD sensors that are less affected by lighting conditions.