Lens Distortion
Geometric aberration where straight lines in a scene are rendered as curves due to lens optical properties. Barrel and pincushion distortion are the two primary types, most pronounced in wide-angle lenses.
Lens distortion is a geometric aberration where straight lines appear curved. Pronounced in wide-angle and zoom lenses at widest settings. Architectural photography, surveying, and computer vision treat correction as essential preprocessing.
Distortion is modeled as magnification variation with distance from the optical axis. The Brown-Conrady model expresses radial and tangential distortion as polynomials.
- Barrel distortion: Periphery bulges outward, lines bow from center. Characteristic of wide-angle lenses; fisheye lenses exploit this extremely
- Pincushion distortion: Periphery pulls inward, lines curve toward center. Occurs in telephoto and zoom lenses at long end
- Mustache distortion: Barrel dominates mid-field while pincushion appears at extreme periphery. Found in certain zoom designs
- Correction model: Standard radial model
r' = r(1 + k₁r² + k₂r⁴ + k₃r⁶). OpenCV'scalibrateCamera()estimates coefficients from checkerboard patterns
Modern cameras apply lens profile corrections automatically in JPEG output. Computer vision calibration estimates distortion coefficients for 3D reconstruction, AR, and photogrammetry requiring sub-pixel fidelity.