Radial Distortion
Definition
A geometric lens aberration in which magnification changes with distance from the optical axis. Barrel distortion (negative radial coefficient k1) bows straight lines outward; pincushion distortion (positive k1) bows them inward. Quantified by the Brown-Conrady distortion model coefficients k1, k2, k3.
- Category
- Geometric lens aberration
- Barrel distortion
- Negative k1, lines bow outward
- Pincushion distortion
- Positive k1, lines bow inward
- Model
- Brown-Conrady (k1, k2, k3)
Common questions
Why does radial distortion matter in forensic photogrammetry?+
Uncorrected distortion shifts where straight edges appear in an image, which can introduce measurement error when calculating distances, heights, or trajectories from photographic evidence, so calibration against the lens's distortion profile is required first.
How can radial distortion be corrected before a photograph is used for measurement?+
The camera and lens combination is calibrated, often using a checkerboard target, to estimate the Brown-Conrady coefficients, which software then applies to warp the image back toward true rectilinear geometry.
Related terms
- Brown-Conrady Model
- The standard parametric model for camera lens distortion, using radial coefficients k1, k2, k3 and tangential coefficients p1, p2. Camera calibration tools...
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