[Talk-GB] Stitching Aerial Photographs

[Axel Jacobs]

> I now understand how you managed to put together that set of images so
> perfectly -- and the limitation that it can only be done with a set of
> images taken from the same point.

> > Now that I'm getting more used to the idiosyncrasies of Hugin and co.,
> > I've worked out a workflow that creates usable images. It seems that
> > Hugin is _very_ sensitive to trying to stitch together two images that
> > weren't taken from the same point in space (or for our purposes,
> > anything more than the distance travelled by a plane in 30 seconds or
> > so).

The default settings for Hugin, e.g. the one ones from the Stitching Wizard are designed to work well with single-viewpoints panos. When the images were not taken from the same spot, a new lens needs to be applied to each images. This is necessary, for instance, for combining images coming out of flatbed scanners, for for linear panos:

http://hugin.sourceforge.net/tutorials/scans/en.shtml
http://www.dojoe.net/tutorials/linear-pano/

> [1] P. Pesti, J. Elson, J. Howell, D. Steedly, M. Uyttendaele: Low-Cost 
> Orthographic Imagery, 16th ACM SIGSPATIAL International Conference on 
> Advances in Geographic Information Systems, Irvine, CA, 2008
> http://www.cc.gatech.edu/~pesti/pubs/mapstitcher.pdf

Yes, this paper is definitely a good read. I posted it some time ago on one of the OSM lists. What they are suggesting it that the best results are obtained when the stitching and geo-referencing are done at the some time rather than one after another.

I know the Hugin community is a very friendly crowd. With some funding/help/sponsorship/encouragement it might be possible to implement a geo-mode for aerial photos: Instead of showing two images in the Control Points panel, it could be one image plus a slippy map, a bit like in M$ MapCruncher:
http://research.microsoft.com/en-us/um/redmond/projects/mapcruncher/
Although to implement such a geo-mode  would probably some time. Maybe a joined OSM/Hugin project for Google's SoC...

Blumpsy