1- Images used have been shot tilted up about 21° in front
of a flat building. This "never ending project" is composed of 18
pictures shot in April 2005. Pictures were taken with a 19mm converter lens
monted on a Coolpix 5000 (27mm focal lens equivalent).
Uncorrected image
Loading uncorrected images into PTgui 7.3 and processed as describe here doesn't give a good result even using the new Viewpoint correction feature.
Uncorrected images result
For good result, images have to be shot with the camera exactly perpendicular
to the flat surface which it is not the case here,
we have seen that images were taken tilted up to catch the top of the building
mainly because the lack of space back. See the picture below.
Lack of space for shooting
2- I have tried another method hoping to achieve a better
ouput result.
To work properly Ptgui needs images taken perpendiculary to the subject. So
the idea is loading corrected images as this one :
Corrected image
This has been possible by adding some T1 and T2 parameters to correct the lens distortion in each image.
I've loaded 13 images into PTgui7.3Pro, put manually CPs between each pair and optimized with the Viewpoint button checked.
Optimizer tab
I've created a medium format output and here it is what I've got (small resized) :
Result
Seem surprisingly good at first sight. But if we take a closer look it remains a huge amont of work...
Stitching errors
Some of my personal conclusion : if PTgui 7.3 Pro offer new possibilities to stitch linear panoramas, it is still a long workflow to achieve a decent result if pictures haven't been taken with the camera exactly perpendicular to the flat subject . Beyond despute its new Viewpoint correction option is a great step forward for Nadir shot into 360° panorama. It is probably the case for mosaic stitching and real flat surface like a mural, but at this time I haven't made any try.
You'll find some of my linear panorama work in this page.
Guillaume Fulchiron, 18 october 2007