Re: A first look at DS24

[Tom Droege <tdroege2@earthlink.net>]

Arne and all,

The signed data is a "feature" of the low cost Burr-Brown ADC that I 
use.  But this is just what is stored in the memory card.  Seems to me that 
it could be transformed to any desirable format in the process of writing 
to files.  i.e. Downfits could do it.  It is still my hope that those of 
you that work with this would straighten this out to some reasonable 
format.   So don't blame me.   ;^) Why not fix Downfits so that it writes 0 
- 65535?  Michael, I assume that the pipeline will not care???

Tom Droege

At 08:35 AM 12/23/02 -0700, you wrote:
>I always prefer a 0-65535 representation since that is the way
>most professional and amateur cameras use their ADCs, instead
>of the TASS two's complement.  Changing BZERO is a simple trick
>so that you don't have to add 32768 in some subsequent processing.
>Just be careful about the datatype into which you read the images.
>Of course, Tom will have to quit describing data negatively...
>Arne
>
>Robert Creager wrote:
>>Tom Droege <tdroege2@earthlink.net> wrote ..
>>
>>>>        Can we get a BZERO = 32768. added to the FITS headers?  It would
>>>>make life much easier
>>>>when using CFITSIO.
>>I vote for this!  I've done just that on the download program I'm 
>>currently using (downfits child).  I can re-release downfits with this in 
>>place if desired.  The current release of downfits won't allow you (Tom) 
>>to specify BZERO within the constant or plate files, so that won't work.
>>Ted, in the mean time, what I've done in my CFITSIO programs which work 
>>on TOM images, I add the following right after I open the image:
>>int type;
>>fits_get_img_type( ftpr, &type, &status );
>>if ( type == SHORT_IMG )
>>    {
>>    fits_set_bscale( ftpr, 1, 32768, &status );
>>    }
>>Cheers,
>>Rob
>>
>
>