Smartphone Camera

Smartphone cameras are the primary tool for scanning QR codes today. Since iOS 11 added native QR recognition to the Camera app in 2017, followed by Android's Google Lens integration, dedicated scanner apps are no longer necessary. With global smartphone penetration exceeding 70%, the smartphone camera is the de facto standard for QR code scanning.

The scanning process detects finder patterns (the three corner squares) in the camera image, identifies the QR code region, and decodes it. Processing begins once autofocus locks, so scanning fails in conditions where focus is difficult (low light, extreme distances). A practical scanning distance is 3-10 times the QR code's side length - a 3 cm code reads reliably at 9-30 cm.

Three practical tips improve scan reliability: ensure at least 4 modules of quiet zone (margin) around the code; maintain strong contrast between code and background (black on white is most reliable); and avoid glossy print surfaces that cause flash reflections and washout.