[GRASSLIST:2807] Re: image correction tools

[werchowyna at pf.pl]

thank you for your help Markus

one thing more: how do I correct the effect of uneven lighting conditions in
aerial photos?
(some areas are brighter like if there was a spot-light or a flash cast on
it and some are unnaturaly dark)

Regards
Maciek

----- Original Message -----
From: "Markus Neteler" <neteler at itc.it>
To: <GRASSLIST at baylor.edu>
Sent: Tuesday, March 02, 2004 10:17 AM
Subject: [GRASSLIST:2799] Re: image correction tools


> On Mon, Mar 01, 2004 at 11:49:12AM +0100, werchowyna at pf.pl wrote:
> > hello Everyone!
> >
> > this my first post to GRASSLIST
> >
> > since it's not strictly GRASSy you may answer directly to me
> > werchowyna at pf.pl
> >
> > I'm looking for a Grass module/standalone software (both Linux and
Windos)
> > for radiometric (solar, atmospheric, topographic) correction of aerial
and
> > satellite images  of subalpine and alpine areas
> >
> > open source/freeware/cheap preferably
> >
> > can someone help?
> > any ideas where to ask?
>
> There is an implementation of "6S" in GRASS:
> http://grass.itc.it/grass_addons.html
>  -> i.atcorr: 6S atmospheric correction program (Christo Zietsman, South
Africa)
>
> Concerning terrain correction we are suggesting a simple method
> with r.mapcalc etc in our book (http://mpa.itc.it/grassbook/).
> Basically it is using the terrain geometry (slope, aspect), sun position
> and the calculation of a normalized map. The upcoming second edition of
> the book will describe a slightly improved method. It's not very
> difficult.
> An older version is here (my MSc thesis, 1999):
>
http://www.geog.uni-hannover.de/users/neteler/itc_irst/atmos_sma/9_atmos.htm
l
> (click onto the right buttons to proceed).
>
> You should be sure to have an elevation model with a resolution
> which corresponds to the resolution of the aerial or satellite image.
>
> Best regards
>
>  Markus