[ptx] Using nona before autopano-sift for ultra wide-angle lenses

[Sebastien Perez-Duarte]

On 8/8/06, Daniel M. German <dmgerman at uvic.ca> wrote:
> [clens]
> will remove the distortion (although the edges will still be naturally
> distorted due to the fact it is a rectilinear lens).

The distortion that bothers most autopano seems to be the rectilinear
distortion.

> Another suggestion is to crop the image before giving it to autopano.

Hum, but then I loose part of the appeal of having a wide angle lens...

>  Sebastien> 1) [...] I could then
>  Sebastien> use nona or PTStitcher to transform these images [...]
>
> this is easy. Create automatically a script for PTmender.

OK, no problem with that.

>  Sebastien> 2) autopano-sift could then be used [...]
>
> Then give the resulting images to autopano (perhaps in pairs, given
> that you know the location of the points).

No problem with that at all
>
>  Sebastien> 3) Some process (hopefully not very hard to program out of the PT
>  Sebastien> tools) then projects the control points found on the transformed
>  Sebastien> images back to the original rectilinear coordinates.
>
> The .pto file is easy to generate from the ones you get form autopano.

There I'm not so sure it is "easy". Autopano gives the coordinates of
the control points on the "equirectangularly" projected image, and
these coordinates have to be retransformed. I'm not entirely confident
I can do this easily, and exactly in the inverse way PTmender did it
the first time (step 1)