The wide-angle lenses (or rather zoom lenses when set to short focal length) typically produce a pronounced barrel distortion. This lens distortion affects damage mappings (i. e. the superposition of damage photographs) as well as perspective rectifications. Lens distortion can however be mostly corrected by applying suitable algorithmic transformations to the digital photograph.
The paper presents the algorithms used for this correction, together with programs that perform either the entire task of correction or that allow one to determine the lens correction parameters. The paper concludes with some (rectified) example images and an estimation of the gains in accuracy achieved by applying lens correction algorithms.