Talk:Align image stack

Some findings from my experiments with Stereo image parameters in align_image_stack

The parameters I believe that apply are: -i, -S, -A, -P. The command I finally ended up with was: /Applications/Hugin/HuginTools/align_image_stack -i -a AIS_ -S -A -P IMG_????.JPG

From others I received the following note: "This feature was implemented by Vladimir Nadvornik (http://groups.google.com/group/hugin-ptx/browse_thread/thread/eb25297bdc55102b). See http://vndlinuxphoto.blogspot.de/2011/01/stereo-image-alignment-in-hugin.html for a tutorial and more details."

   -i  -  Optimize image center shift for all images, except for first.

I added this parameter because Vladimir used it in his tutorial mentioned above. Without it the second image I experimented with tended to have some blank space along the left edge. When I used -i that space seemed to diminish and be better balanced between the left and right edges; ... centered it it did.

The first time I tried aligning my two images I didn't use any of the options -i, -S, -A, -P ... the effect was a 3D rendering but I believed the 3D effect looked better towards the outside of the image when I adding in the -S parameter.

   -S  -  Assume stereo images - allow horizontal shift of control points. 

Without the -S option the right image was about 1.5% shorter between horizontal points then the left. With the -S option this changed to about 2.3% (which matched the difference in the original images). I was mostly moving away from the scene in my images so I think this foreshortening is a normal effect and should remain the same as the originals, as happened using the -S parameter.

   -A  -  Align stereo window - assumes -S.

???

   -P  -  Align stereo window with pop-out effect - assumes -S.

It seems that this refers to the idea of part of your image appearing to be in front of the screen plain; that is, parts of the picture seem to "pop-out" of the screen. With my mountain scene it didn't seem to have an effect ... maybe it would if there was something in the image a lot close to the camera. So, without -P everything would be deeper then the screen itself; whereas with the -P option you can have things jump out at you.