tripod/nadir problems

[Matthias]

Hello,
I have a quite simple problem but coudn´t find an adequate answer yet.
When I create a 360*180 degree picture there are the legs of the
tripod in the lower part of the image (in VR you can look on the
tripod from above.
If I try to remove the tripod with ptgui pro (crop and/or nadir image
with viewpoint correction) the results are very bad and you can still
see parts of the tripod.
My question: How is the workflow to get a good result? In the tutorial
regarding viewpoint correction there were no pictures where a tripod
or parts appear.

Fyi: I ´m taking multi-row pictures. 3*10 (45 degree angle) +1nadir

Many thanks in advance!

Matthias

[Keith Martin]

Sometime around 14/9/09 (at 06:47 -0700) Matthias said:

>If I try to remove the tripod with ptgui pro (crop and/or nadir image
>with viewpoint correction) the results are very bad and you can still
>see parts of the tripod.
>My question: How is the workflow to get a good result? In the tutorial
>regarding viewpoint correction there were no pictures where a tripod
>or parts appear.

I find that I need to add alpha channels to the images with the
tripod legs or those are rendered into the final composite result,
trumping the viewpoint-corrected nadir image.

I sometimes also make an alpha channel mask in the nadir image to
hide parts around the edges that are not wanted in the final result,
such as pillars, legs, and anything else that isn't fairly flat.

Regarding getting a good alignment, follow the tutorial to the
letter. I got tripped up a few times but it usually works well for me
now.

k

[John Houghton]

You can also increase the blend priority of the nadir image on the
Image Parameters tab so that more of it gets used. You can judge the
amount needed by displaying the blended panorama in the Panorama
Editor window.

John

[HansNyberg]

But of course the easiest and most logically is to adjust your setup
so that your lower row does not include the tripod.
Unless you have a panohead which only have positions every 5 or 15
degrees this is the easy way which will save you a lot of work in the
future.

Hans

[Matthias]

dear all,
thanks a lot so far.
Indeed, I can change the setup but I thought there is an quite good
"software solution". When changing the setup I´m afraid that therefore
you lost a lot of important information for stitching. With alpa-
channel I will try next time, I have no experience.
Blend priority: I thougt so far this is the way to avoid blending
errors with the nadir and the other pictures? But there you have to
decrease. I will try to increase an then I will see...

For all who work with fisheye lenses: Do you use a certain angle when
shooting the pictures (to avoid getting the tripod)?

Best regards
Matthias

[HansNyberg]

That depends on what camera and fisheye you use. And of course also on
the tripod.
I shoot with a 5D and a 15mm fisheye 6 + 1 zenith + 1 nadir. I use a
special tripod with very small foot-print so at -10 degree I get the
tripod legs right at the edge and I still have a very small hole in
the nadir.

Hans