In order to ensure that the remote sensing data sets are consistent and that changes identified through multi-temporal analysis are indeed actual changes in surface properties and not triggered by changed illumination and extinction conditions, it is important to correct for effects of atmospheric attenuation of the signal recorded at the sensor, as well as for illumination variations within the scenes resulting from the sun-sensor-surface constellation.
As far as I saw, there are no GRASS functions to perform Radiometric Correction. The only reference that I found was related with Conversion of DN’s to absolute radiance values==> GRASS book refers it as Image Calibration from DN to apparent radiance at sensor.
Is there any function to perform radiometric correction? or anyone has developed something like that?
Thanks
Best regards,
Nikos
On Wed, Feb 3, 2010 at 4:43 PM, Nikos Dumakis <nikosdu1980@gmail.com> wrote:
In order to ensure that the remote sensing data sets are consistent and that
changes identified through multi-temporal analysis are indeed actual changes
in surface properties and not triggered by changed illumination and
extinction conditions, it is important to correct for effects of atmospheric
attenuation of the signal recorded at the sensor, as well as for
illumination variations within the scenes resulting from the
sun-sensor-surface constellation.
As far as I saw, there are no GRASS functions to perform Radiometric
Correction.
There is: i.atcorr.
The only reference that I found was related with Conversion of
DN's to absolute radiance values==> GRASS book refers it as Image
Calibration from DN to apparent radiance at sensor.
Is there any function to perform radiometric correction? or anyone has
developed something like that?
Yes, please see
http://grass.osgeo.org/wiki/Atmospheric_correction
Markus
Hello Markus. Thanks for your answers
As far as I saw, there are no GRASS functions to perform Radiometric
Correction.
There is: i.atcorr.
Regarding i.atcorr I thought that the only thing i.atcorr perfoms is the atmospheric correction, I mean conversion from TOA (top-of-atmosphere) to BOA (Bottom-of-atmosphere).
But how about the correction of illumination variations and instrument calibration? 6S also includes this?
(by the way, at i.atcorr manual one of the links (INPE) is dead)
I.atcorr is equal to 6S models provided by Maryland Univ group?
Regarding Geometrical conditions:
- Is it possible to addapt this to a SPOT image or UK-DMC image? I mean there is a list of pre-defined bands and those satellites, among others, are not there. But it is possible to apply this model to others satellite images?
Yes, please see
http://grass.osgeo.org/wiki/Atmospheric_correction
Regarding The estimation the overpass time from the sun position:
Is this retrieved information useful for the i.atcorr process right ? and is this information placed automatically in the ICND file?
Thank you for your help Markus
Best regards
Nikos
On Thu, Feb 4, 2010 at 10:36 AM, Nikos Dumakis <nikosdu1980@gmail.com> wrote:
Hello Markus. Thanks for your answers
As far as I saw, there are no GRASS functions to perform Radiometric
(by the way, at i.atcorr manual one of the links (INPE) is dead)
The INPE link was for Mauro A. Homem Antunes home page and now he is
at Federal Rural University of Rio de Janeiro. He still maintains a
web page where you can download his 6s fortran code (web page in
Portuguese though). The link is:
http://www.ufrrj.br/institutos/it/deng/mauro/downloads.htm
Cheers
Daniel
Thanks. I have a portuguese friend that can help me 
And regarding i.atcorr code, is based on Mauro’s code or the original one?
Nikos
On Thu, Feb 4, 2010 at 5:19 PM, Daniel Victoria <daniel.victoria@gmail.com> wrote:
On Thu, Feb 4, 2010 at 10:36 AM, Nikos Dumakis <nikosdu1980@gmail.com> wrote:
Hello Markus. Thanks for your answers
As far as I saw, there are no GRASS functions to perform Radiometric
(by the way, at i.atcorr manual one of the links (INPE) is dead)
The INPE link was for Mauro A. Homem Antunes home page and now he is
at Federal Rural University of Rio de Janeiro. He still maintains a
web page where you can download his 6s fortran code (web page in
Portuguese though). The link is:
http://www.ufrrj.br/institutos/it/deng/mauro/downloads.htm
Cheers
Daniel
Thanks. I have a portuguese friend that can help me
And regarding i.atcorr code, is based on Mauro’s code or the original one?
Nikos
On Thu, Feb 4, 2010 at 5:19 PM, Daniel Victoria <daniel.victoria@gmail.com> wrote:
On Thu, Feb 4, 2010 at 10:36 AM, Nikos Dumakis <nikosdu1980@gmail.com> wrote:
Hello Markus. Thanks for your answers
As far as I saw, there are no GRASS functions to perform Radiometric
(by the way, at i.atcorr manual one of the links (INPE) is dead)
The INPE link was for Mauro A. Homem Antunes home page and now he is
at Federal Rural University of Rio de Janeiro. He still maintains a
web page where you can download his 6s fortran code (web page in
Portuguese though). The link is:
http://www.ufrrj.br/institutos/it/deng/mauro/downloads.htm
Cheers
Daniel