Re: Cloud detection

["Robert Creager" <Robert_Creager@LogicalChaos.org>]

Hey Tom,

If all you want is the mean and sigma of some portion of an image, I have a C 
program already written which does that, right now.  It takes a start/end pair, and 
prints out the number of samples, the sum, mean, min, max & sigma.  It's not 
prettied up, in that it's unforgiving of input errors and offers no help, but it does 
work.  If you like, I can send you a binary 'now'.  Here is the output from a sample 
run.  You will notice that I read the data with an offset of 32768 added in (by using 
CFITSIO's capabilities) to only work with positive data.  It twists my simple mind too 
much to deal with data values < 0...

[robert@chaos tassiv_reduce]$ stdbox 200 300 200 300 
/tass/data/2157/h?ra2157696.fits

----
Doing file 1 of 2
Fri Jun  7 22:02:26 MDT 2002
----

   file = /tass/data/2157/hira2157696.fits
samples =                          10201
    sum =                      103444033
   mean =                          10141
    min =                              2
    max =                          23092
  sigma =                            437

----
Doing file 2 of 2
Fri Jun  7 22:02:27 MDT 2002
----

   file = /tass/data/2157/hvra2157696.fits
samples =                          10201
    sum =                       96235035
   mean =                           9434
    min =                              2
    max =                          23092
  sigma =                             86

Also, I know one of the 'ftools' does this also, but I forgot which one and don't have 
it running on my machine right now (library problem that I didn't know I had 'till now).

Cheers,
Rob

Date sent:      	Fri, 07 Jun 2002 21:01:16 -0500
To:             	tass@listserv.wwa.com
From:           	Tom Droege <tdroege2@earthlink.net>
Subject:        	Linux RPM

> 
> If you have energy to do a (not so) big software project, how about
> thinking about how to pre-process the tass raw data to filter out
> problems caused by clouds.  That project is next on my personal list. 
> That is why I want iraf.  My hope is that a simple call to Iraf will
> give me the mean and sigma for a portion of an image.  I could then
> try my scheme of cloud rejection.  I would be glad if someone else
> took on this project.  I have looked at enough data now to be pretty
> sure that clouds can cause larger errors.   Not a big surprise.
> 
> Tom Droege
> 
> 
>