Perspective Correction

Perspective correction transforms trapezoidal distortion from angled photography back to a square using projection transformation matrices. Essential for QR decoding since users rarely scan from directly in front.

Scanners calculate distortion from finder pattern positions - analyzing how the expected squares are deformed and applying inverse transformation. Accuracy depends on finder pattern detection; extreme angles or partially hidden patterns cause failures. Place QR codes where users can scan from 30+ degree angles.