Hi Bart,
It seems to me that ptGUI and ICE allow you to project the data in various ways, and you may be able to find a setting that results in an apperance that is more rectangular than other choices, and then you crop the output your best ability.
Hi,
Not only does PTGUI allow to choose a more appropriate projection, but it also allows to take out the curve that's caused by using an improper pitch value. That will already take care of having to crop to top and bottom at all. What's left is the visual impression that is caused by looking at the super wide angle image from too far away. PTGUI allows to adjust some of that by squeezing in the horizontal stretching.
On the other hand, if you are confronted with an improperly stitched image from another application, then Affinity Photo already has the tool you are looking for. Attached an example of using the 'Mesh Warp tool' where I, in Source mode, only defined 2 corner points for the upper arched edge in source mode, dragged the center of the connecting line to follow the edge, and did the same for the bottom arched edge, and then switched to destination mode and I applied the resulting distortion.
The resulting keystoning can then be removed by using the perspective tool, and then virtually nothing needs to be cropped or inpainted. But such warps and distortions do affect the final resolution a bit. Doing it while stitching retains resolution better.
Affinity Photo's tools are simple and powerful, but the
need to use them can be avoided with a proper stitch.
Cheers,
Bart
P.S. Here's an Affinity Photo video tutorial that shows a similar correction on a panorama of a building, which is more tricky due to the straight lines involved:
tutorial