[GRASSLIST:9548] Re: rectifying images

[Markus Neteler]

hi,

a student of us has implemented improved versions of
i.points and i.rectify based on previous work as published
in our last year's Bangkok paper.

The new version
- use FFT correlation to automatically search for ground
  control points in a user given window pair (so, just zoom
  more or less the same zone in the master and the slave
  image)
- do this for the entire stripe of images
- bad GCPs are identified and eliminated
- run the modified i.rectify to rectify the entire stripe.

We are using this to geocode historical images. I still
have to cleanup the code to the current coding standards,
then I need a beta tester :-)

If course you can also work with just 2 overlapping images
and enjoy the automated GCP search.

Interested?

Markus

On Fri, Dec 16, 2005 at 03:13:03PM +0100, Wolfgang Zillig wrote:
> I'm not sure if this helps for my problem (perhaps I was not clear 
> enough in my description). The problem is, that I have one original 
> images which I want to use as reference and all others are more or less 
> deformed but no one at the same level. So I think I will have mark my 
> reference points in all deformed images. When I understand right 
> grouping is good, when you have many images whith the same deformation, 
> or am I wrong?
> 
> Wolfgang
> 
> Hamish schrieb:
> 
> >>I need to rectify several images in the next time. Is there a way to
> >>automatize this procedure a little bit? I have the "original" image and
> >>then about 10 to 20 images which needs to be corrected that they refer
> >>to the original one. I thought of something like saving the correction
> >>points of the original image to an file, so that I don't need to mark
> >>again (the reference points will be the same for all images) and I only
> >>need to specify them in the images which needs to be rectified.
> >>   
> >>
> >
> >
> >Add all the images to a group, then rectify the lot.
> >
> >i.group input=name[,name,...]
> >
> >i.rectify -a
> >
> >
> >
> >Hamish
> >
> >
> > 
> >
> 

-- 
Markus Neteler     <neteler itc it>       http://mpa.itc.it
ITC-irst -  Centro per la Ricerca Scientifica e Tecnologica
MPBA - Predictive Models for Biol. & Environ. Data Analysis
Via Sommarive, 18        -       38050 Povo (Trento), Italy