Distortion correction fine tuning with known lens distortion profile

This tool is designed to help the user fine tune the Distortion Correction setting provided a lens distortion profile is already known. Three curves are plotted in the graph at the upper-left corner of the Distortion Correction page. The green one is the given lens distortion curve which is used as a reference for further fine tuning. Ten control points are exposed to the user: 40, 80,…,800 (radius in the Distortion Corrected image, in the unit of pixels). The user may either move the slider or enter a desired value in the edit box and then enter a space key, all those operations will cause the Desired Gain blue curve to change. Keep adjusting the blue curve until the Fitted Gain red curve matches your expectation.
The big red dot at coordinates (240,240) is an anchor point which the red curve should pass through.
Distortion Correction center horizontal (vertical) coordinate can be specified in Distortion Correction Center Horizontal (Vertical) edit box.
Perspective Correction can be enabled and disabled during Distortion Correction fine tuning process.
Two curve fitting options are available: manual and automatic, if the user selects Automatic, all the control points within Maximum Radius will participate Fitted Gain curve computation. You can decide how many control points are needed for Fitted Gain derivation by selecting Manual and enter a desired value in Maximum Radius edit box (recommend entering 800).
The user may move all the sliders up (down) by a scaling factor, for example if you enter 1.1, and then click on Scaling Factor button, all the new slider values will be 1.1 times of the current values.

Fig. 7 Distortion Correction Page