[GRASS-user] help on imge registration

Luigi Calori l.calori at cineca.it
Thu Oct 18 09:01:54 EDT 2007


I' quite a novice user of Grass and trying to use it for a non 
conventional task:

I need to register a series of images of an almost planar object to find 
out modification.
I' ve decided to use Grass in the following way:

1) take one of the images that has metric references , using i.points I 
set up a sereies of reference points on the image and then I use 
i.rectify wint secon order polinomial to warp the image ino a "rectiied, 
metric one"
    (the coord system is XY, planar)

2) for all the other images, I use i.points on the rectified image

Now the questions:

1) are i.rectify and i.point able to handle homographies?
 I' ve found a nice reference paper on 
http://gisws.media.osaka-cu.ac.jp/grass04/viewpaper.php?id=37
but I did not fund anything in grass62 neither browsing thru CVS.
Are these modules needed to handle homographies transforms ?

2) there are also other modules like photo.camera photo.2image 
photo.2target photo.rectify  I did not used them because they reqired 
camera parameters I do not have.
Are they able to handle homographies?

Thanks in advance
                                Luigi




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