Sebastian Nibisz wrote:I'll think about how to implement this correction.
Hi Sebastian,
Allow me give you some ideas to impove on what others have done. The usual corrections for Lateral Chromatic Aberrations (LCA) involve a radial enlargement of one or two of the color channels, in order to align all three of them if there is a poor registration. The usual simplification is to assume a radial enlargement from the image center. However, most lenses have a slight decentering of the optical elements. In addition, there are lenses, e.g. tilt and shift lenses, that allow a significant user defined decentering to use a different part of the projected image circle and which can vary from shot to shot.
So to do a better job than the competition, the solution should also automatically determine the center of the aberrations before resizing the color channels radially.
When the LCA is not corrected prior to tonemapping, then the colorful fringes may get 'enhanced' by the tonemapping and the image becomes even more difficult to correct afterwards. LCA correction is the first step, preferably even before Raw demosaicing. This is not a simple issue to solve but it can make a big difference in the individual exposures when Raw is used, or when the images were not corrected when they could have been.
If you need a sample file from my TS-E 45mm lens (which has significant CLA), and the image can also be a shifted version if you want to test your solution, just let me know by PM or e-mail.
Cheers,
Bart