Barrel distortion

Barrel distortion is the opposite of pincushion distortion.

A photograph showing exaggerated barrel distortion

Tools to correct barrel distortion

• The original PTStitcher can be scripted to batch process images with known a, b & c parameters. It can also be operated with one of the GUI tools such as PTGui, PTAssembler, hugin or PTMac.

• nona or nona_gui (both part of the hugin distribution) can be used identically to PTStitcher.

• The Correct filter in the Panorama Tools Plugins for the gimp or photoshop uses the same a, b & c parameters as PTStitcher. Note that it doesn't know about d & e parameters and uses 'd' as an overall scaling factor instead.

• PTLens is a Photoshop plugin and a stand-alone Windows tool that uses the same a, b & c parameters and comes with a database of popular lenses.

• Clens is a command line version of PTLens.

• Gimp wideangle plugin uses a different formula altogether to correct distortion.

• Gimp phfluuh plugin is another tool that corrects lens distortion using yet another formula.

• CamChecker is a tool for automatically determining lens distortion and generates a different set of parameters from everything else.

• zhang_undistort is a tool distributed with hugin that uses CamChecker parameters to actually correct distortion.