Re: [PanoTools-devel] portable lens correction

[Thomas S. <tks...@gm...>]

Sorry, I keep hitting TAB, which makes gmail send.

On Sun, Jan 23, 2011 at 10:03 PM, Thomas Sharpless <tks...@gm...>wrote:

> Hi all
>
> I've just finished what I hope will be the final revision of the Wiki page
> http://wiki.panotools.org/Lens_Correction_in_PanoTools
>
> It is now, I hope, a clear statement of how PT computes correction
> parameters, why those are not portable between image formats, and what needs
> to be done to make them portable.
>
> Bottom line, I think:
>   -  add the physical pixel width in microns and the fitted focal length in
> mm as new 'i/o' parameters.
>
      -  compute the source fl in pixels from these if present (portable
input), from fov if not (trad input)
      -  provide  calls to get and set pixel width in microns.   If no size
has been set (trad input) get should return 0.  Passing 0 to set should be
ok and mean "use input value" (0 if input is trad).
      -  Save params as portable when a nonzero pixel width has been posted
(portable input or app set new width).
      -  use 'portable' radial() parameters internally when script has
portable params.  Otherwise use trad ones and convert the params on output
if a pixel width has been posted.
      -  for trad input and trad app only, use and save trad parameters.

This reduces the job of front ends to the bare minimum, of acquiring and
posting sensor specs.  It requires no new behavior when the source format
has not changed -- that covers all presently valid use cases.  And
eliminates the rotated source problem (provided the camera has square
pixels) .

The most important benefit, IMO, is that apps that need lens correction
would be able to use PT parameters, even if they don't use libpano.

Best, Tom