Nona

nona is a drop-in replacement for PTStitcher and is part of Hugin.

Like PTStitcher and PTmender, nona performs geometrical and photometric distortions on photos and writes the output to image files. The parameters are specified in the .pto project file, i.e. nona doesn't decide what the distortions are going to be, it just does the remapping part of the stitching process. It can also blend images in memory in the same way as verdandi. The parameters for remapping can be calculated in Hugin or with autooptimiser on the command line.

The format of the project file is documented here: PTStitcher Example_Script, and here: http://hugin.sourceforge.net/docs/nona/nona.txt.

Advantages

Unlike PTStitcher, nona has full source-code availability, this means that it can be used on many more platforms such as OS X, Linux x86_64, linux powerpc, Solaris and IRIX.
When set to use cropped TIFF output, nona doesn't perform expensive transformation calculations for unused areas of output images. For panoramas consisting of many source photos this can speed things up greatly.
nona implements vignetting, white-balance, brightness and camera response curve correction at the stitching stage.
multi-threaded processing uses as many CPUs as are available.
nona supports HDR images for input and output.
nona supports GPU stitching with graphics hardware
nona can merge 8bit low dynamic range bracketed shots into HDR output.

Disadvantages

(Note: this is the situation as of May 2007, please correct this page if you know this has changed)

Morph to fit[*] control points are not supported.
It doesn't yet support the fast transformation option added to pano12 by Fulvio Senore[*].
It doesn't support the adaptive filtersize anti-aliasing filters added to pano12-2.7.0.11
It doesn't support C-type cropping[*] and hence is not compatible with other GUI front-ends[*] than hugin if used for images that need cropping (like circular fisheye or scanned ones).