[ptx] Hugin architectural projection tutorial

[Stroller]

On 12 Mar 2006, at 07:33, Martin Proetzsch wrote:
> 1. The bending of the image is caused by the projection you  
> chose.The tutorial
> says" "Change the Panorama type to rectilinear and calculate  
> visible field of
> view (we don't have enough photos for a full 360 degree  
> equirectangular
> panorama)."

I thought that "Normal (rectilinear)" was the default and that I left  
it as such throughout. And that I clicked on "calculate" for each  
run. But I could be incorrect.

> 2. The control points for your vertical lines are not set properly  
> as can be
> seen in the screenshot at
> http://photography.stroller.uk.eu.org/Problems/Hugin/Screenshot.png
> First deactivate "auto estimate". For a vertical line choose a  
> point in the
> left image and afterwards a _different_ point on the same vertical  
> feature in
> the right image (the bigger the distance to the first point the  
> better). In
> your screenshot all pairs of points are nearly in the same place,  
> probably
> due to hugin auto estimating matching points. The "auto estimate"  
> feature is
> only useful for stitching images.

Ah! Many thanks for this, Martin. You have hit the trouble precisely.  
In fact, I read your message, and Daniel's, and _still_ completely  
failed to understand what I had done wrong, and spent more time  
playing with Hugin trying different "control points" with no success.  
My failure in understanding was compounded by the fact that I  
returned to the image and deleted & re-entered one of my "control  
lines" (still incorrectly clicking top & bottom in both images of the  
GUI) and by sheerest chance the image turned out with much improved  
parallax correction; it was weirdly rotated & off-centre of an over- 
sized canvas, but I assumed that this was the way it was "supposed to  
be".

It was only as I prepared to reply to you that I suddenly  
comprehended your message!

Of course my unfamiliarity with Hugin's GUI had caused me to create  
vertical control-lines that were only a pixel or so long, and this  
was what caused my problem. As soon as I realised my mistake,  
disabled "auto-estimate" and used only the left image for start  
points of the vertical control-lines (the right image for end points)  
it worked perfectly!

Many thanks for your help,

Stroller.