[GRASSLIST:951] orthorectification

[olivier.faivre at free.fr]

Hi,

First of all, i'm beginner with GRASS usage.
I have a set of aerian pictures which followed each others, with about 60% of
common coverage. My goal is to obtain a unique color picture orthorectified and
georeferenced.

1°) I've scanned my aerian pictures to obtain tiff files. I've imported them in
grass using r.in.gdal, so i've 3 rasters files (RGB) by aerian pictures.
I've done the orthorectify process, picture by picture, working with the 3
rasters RGB of one picture at a time.
Is it the good way to do it, or is there a faster way to do it?
isn't it better to gather the 3 RGB rasters using r.composite and then going on
the orthorectification process on this picture, or on a group of composite
pictures belonging to my set of aerian pictures?

2°) Once the orthorectify process is done, i've got many orthorectified and
georeferenced rasters.
So i've used r.composite to gather RGB rasters of a same picture.
then, I've got many composite rasters, orthorectified and georeferenced, each
raster having part of itself in common with another raster (common coverage of
60%) and each raster having uninteresting informations (fiducial marks, black
strip surrounding the picture itself, aerian picture indicators as focal, ...)
that needs to be suppressed.
How can i do now to gather all these rasters to have a single accurate
orthorectifed and georeferenced raster without the uninteresting informations,
and taking advantage of the commun coverage of the rasters to improve the
quality of this unique raster, for exemple in attenuating the errors due to the
camera on the edge of each aerian picture.
I've thought to use i.image.mosaic or r.patch, but i don't know what to do with
it....
Can i do what i wwant using Grass? or do i need another software? if so, do you
know open source software coping with my needs

3°) I work on windows server (w2000 server SP4), with a Pentium IV 2.8 GHz, 1 Go
RAM, so i use cygwin and "d.m" interface
I use grass version 6.0.0
Is it normal that display process, and more over pointing with mouse or zoom
processes were some time very very long, freezing completely the server...

thanks for your answer
best regards

Olivier