On 18 Feb 2006 at 7:27, Cory Papenfuss wrote: > Rectilinear (i.e. "normal") lenses cannot mathematically represent 180 > degrees of field of view. So, correcting for severe fisheye can remap > perspective, but it's not the lens' fault that things look weird when one > goes too far: > http://www.ee.vt.edu/~mythtv/PESO/imgp3342_defishedrect140.jpg > http://www.ee.vt.edu/~mythtv/PESO/imgp3342_defishedrect150.jpg > http://www.ee.vt.edu/~mythtv/PESO/imgp3342_defishedrect160.jpg > > Those are 140, 150, and 160 degrees of horizonal view. I'd say > that 140 is about the most that can be done and still seem realistic. > > By contrast, here's an equirectangular projection of the same > shot. Less "fishy" than the original, although straight lines don't stay > straight. At least the whole shot is viewable. > http://www.ee.vt.edu/~mythtv/PESO/imgp3342_defished.jpg
I tend towards plain cylindrical projections for images of greater than about 140 degrees as I find that the apparent distortion is often less objectionable. > Enough babbling... just figured I'd encourage anyone who hasn't > played with hugin or its other panoramic ilk to play. This correction was > trivial.... set the lens at 8mm, 1.5 crop, and choose how big I want the > output. The nice thing with Hugin is given a few images with sufficient overlap the distortion parameters of any lens can be determined and this profile then saved so that the distortion correction can be applied to discrete images. I also use Hugin to produce panos, for rotation and perspective correction, to correct lenses geometric distortion to align images that I wish to overlay and manipulate and to re-map images to alternate projections, it's very flexible once understood. Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications/ Pentax user since 1986, PDMLer since 1998
