[ptx] Lens correction of a cheap webcam

[Bruno Postle]

On Wed 14-Jul-2004 at 12:19 +0300, Marko Mäkelä wrote:

> I got satisfying results with the David Hodson's "wideangle" GIMP plugin
> (http://members.ozemail.com.au/~hodsond/).  I'm not aiming for perfect
> images; I'm only trying to get rid of clearly noticeable distortion.
> 
> Could you tell me how the five parameters your script relate to the
> parameters of Mr. Hodson's plugin?  I think it would be easier for me
> to base my work on his C code.

They don't, David Hodson couldn't get panorama tools to install, so
he came up with his own algorithm :-P

I was going to recommend using nona but, even when stripped, the
binary would fill a floppy disk.

In my perl script:

$a, $b, $c, $d & $e are equivalent to Helmut Dersch's lens
correction parameters (ie. the same as hugin).  They can be
summarised as:

  a - central barrel distortion
  b - general barrel distortion
  c - peripheral barrel distortion
  d - horizontal shift
  e - vertical shift

The script also does crude radial luminance adjustment and linear
interpolation.

-- 
Bruno