The lens distortion tool offers the ability to manually enter distortion correction parameters to apply the correction. This tool is made available in the menu when the tool.lensdistortion.enable property is set to 1.
Two algorithms are currently available, PanoTools ptlens (also used in lensfun), and Adobe WarpRetilinear. The scaling parameters can be auto-calculated by enabling the checkbox by the algorithm specification. Parameters for both algoritims can be entered; only the paramters for the selected mode will be applied.
A paramter reset button is available for each mode. It will reset the paramters to those initally loaded in the tool.
Properties: See tool.lensdistortion.* in Configuration Properties