[ptx] stitching 3 pictures with hugin

[Bruno Postle]

On Wed 21-Dec-2005 at 09:48 +0800, xdenly wrote:
>
> I am a beginner in stitching, and have no idea of how many control 
> points and how should the control points be placed.  Is there some 
> rules to be followed when stitching?

It depends on the number of parameters you are optimising.  

If you are only optimising photo 'positions', then two control-point 
pairs between each photo can be sufficient.  If you are optimising 
'everything' then you need a lot more.

Control-points should be evenly spaced around the overlap between 
the photos; though if there are parallax errors caused by camera 
movement, you need to concentrate points around features that need 
to be best aligned.

> And in which situation should I use the Horizontal Line and 
> vertical line?

Horizontal and vertical control points do not improve the stitching 
alignment between photos, they only influence the final output image 
rotation (except in rare cases).

-- 
Bruno