I too have a question concerning bUnwarpJ registration.
I can follow the example and your video tutorial. However, I see that unwarping of your image of the Eifel tower in the example you already need to have a perfect picture of the tower. If you only have a camera with very distorting lens you will never have a reference image that you could use as absolute truth. Even if there was one official image or you would pick out a postcard that you would like to use as reference, it would never line up with your image.
What are strategies to work around this conundrum?
What is a good choice of reference image?
If you create a synthetic image first for example of a grid of points, a chess board or Escher’s birds and fish. Then print this pattern and image it with the distorting lens you would still have to be concerned with the quality of the print, the perfect positioning of the camera so that during the effort to correct the barrel or pincushion of the lens not additional distortions from perspective or uneven focus are introduced and end up in the transformation correction that would be applied to all future images with this lens and possibly make things even worse.
Please advise how your plugin could be used to solve this problem or please point me to other workflow that could.
Edit after posing the original question:
I now have found
I will have a closer look at the strategies described there.
I also see:
But if you are not working with a TEM but a regular camera it might be difficult to move the camera in an exact plane across a large high contrast planar object maintaining a perpendicular view.
This strategy looks very promising to me, but at this time I can not locate the EasyCalib.exe which seems to be required for the calculation and I do not see the way to apply the corrections that are calculated to a production image to yield an unwarped image for precise angle measurements.