Straightening a (360-degree) panoramic transparency

[psi_mbarnes]

Hey guys,
 
   My problem is that I can't get my horizon line straight. I'm not
stitching together digital camera images. I'm stitching pieces of a
panoramic transparency that is two big to scan at once. Every piece of
software I try doesn't straighten the horizon line. The transparency
was shot with a rotating camera so the horizon has a wave to it. Does
anyone have a clue what or how I could get this to work? I'm using Mac
OSX Tiger.

Thanks,

Matt

[Milko K. Amorth]

Hi Matt,
>  The transparency
> was shot with a rotating camera so the horizon has a wave to it.
There are limits to leveling for horizon in a cylindrical. Especially,
when shot out of level with a scanner.
What I would try is slice the cylindrical projection into several
overlapping segments...depending on the wave, like 6 or 8 segments and
restitch them entirely. The more segments you have, the better the result.

Cheers, Milko

--
Milko K.Amorth
ph:604.561.5101
fx:604.909.5125

www.VRCanada.ca
360° Immersive Imaging
Skype: VRdundee

[bohonus]

--- In PanoToolsNG@..., "Milko K. Amorth" <panotools@...> wrote:

>
> Hi Matt,
> >  The transparency
> > was shot with a rotating camera so the horizon has a wave to it.
> There are limits to leveling for horizon in a cylindrical. Especially,
> when shot out of level with a scanner.
> What I would try is slice the cylindrical projection into several
> overlapping segments...depending on the wave, like 6 or 8 segments and
> restitch them entirely. The more segments you have, the better the result.
>
> Cheers, Milko

You can "level" your completed panoramic image just like any other using tools such as PTGui
etc. You will lose a bit of VFOV though depending on how much you need to correct.

[John Houghton]

--- In PanoToolsNG@..., "psi_mbarnes" <matt@...> wrote:
 
>    My problem is that I can't get my horizon line straight. I'm not
> stitching together digital camera images. I'm stitching pieces of a
> panoramic transparency that is two big to scan at once.

I would do this in two stages.  The first is essentially a flat stitch
to reproduce the full transparency.  You might do that in CS3.  Then
import that into PTGui or Hugin, specifying lens type as cylindrical.  
use t1 and t2 control points to level it if the natural horizon is
visible or there are vertical features present.  Otherwise, drag the
image in the Panorama Editor window to level it visually.  I think the
PTGui web site has advice on how to do that.

John

[salino]

--- In PanoToolsNG@..., "psi_mbarnes" <matt@> wrote:
   
>My problem is that I can't get my horizon line straight. I'm not
>stitching together digital camera images. I'm stitching pieces of a
>panoramic transparency that is two big to scan at once.
 

Hi,

Straigtening panoramas has always been my main difficulty. I solved
this problem with a photoshop plugin : rectinear panorama.

Dominique Salino
New Caledonia
The Clossst Island to Pardise