7 hours ago
(8 hours ago)Ofnuts Wrote:(Today, 12:01 AM)christinanorwood Wrote: This is a stitched panorama (PTGui, 6 images). If this had been taken on film (e.g. 6x17) the facade would be rectangular. Is there any tool in GIMP that can 'rectangularize' such an image? The perspective tool doesn't really work because the falloff is curved.
Film would have produced a distortion as well, because it comes from the technique: ff you are (relatively) close, the things at the center of the panorama are closer to the camera and therefore appear bigger. I have not used PTgui for ages, but it probably has a choice of "projections", some projection produce some kind of bend, while other don't.
Now, to fix the problem at hand, two ways, both in Filters > Distorts
Lens distortion:
Curve bend:
In both cases I eyeballed the result, you can probably get slightly better results
Thanks very much, something to work with and looks promising. I think film would give a rectangular facade because although the height at the side appears less due to greater distance, it's projection onto a flat film plane would be larger (I think) because it's further from the lens (distance from lens to film plane). Certainly Nick Carver's panos taken with his Shen Hao 617 don't seem to suffer from the distortion shown in my image. Using a stitched pano the film plane is essentially a faceted cylinder by rotating the camera.