| Re: mosaic routine? [message #64446 is a reply to message #64436] |
Sat, 27 December 2008 01:23   |
Bringfried Stecklum
Messages: 75
Registered: January 1996
|
Member |
|
|
wlandsman wrote:
> On Dec 26, 11:01 am, Dick French <rfre...@wellesley.edu> wrote:
>> Hi, folks -
>> I'm trying to create an accurate mosaic composite image from about 45
>> tiles. In the simplest instance, no rotations or reprojections are
>> required - just sliding rectilinearly.
>
>
> I presume these are astronomical images == can you get an astrometric
> solution for each individual tile? This would automatically give the
> shift between individual tiles. If I had astrometric information in
> each individual FITS header, then I would probably create an empty big
> image with a FITS header, and use hastrom.pro (http://
> idlastro.gsfc.nasa.gov/ftp/pro/astrom/hastrom.pro ) to map each
> individual tile into the big image. HASTROM uses POLY_2d
> internally which gives the option of using bilinear or cubic
> interpolation for subpixel shifts.
>
> I'd be very surprised if you couldn't get an astrometric solution for
> each tile, given the availability of huge astrometric reference
> catalogs like USNO, and automatic plate solution software like
> astrometry.net.
>
> But if for some reason you need to correlate images to get relative
> shifts, you might look at some very old IDL mosaic software written by
> Frank Varosi ( http://adsabs.harvard.edu/abs/1993ASPC...52..393V ) for
> small infrared arrays, which is still available at
> http://idlastro.gsfc.nasa.gov/ftp/contrib/varosi/
>
> Finally, you might look at the SIMPLE software
> ( http://www.aoc.nrao.edu/~whwang/idl/SIMPLE/MOIRCS/Doc/index. html)
> which is designed to create a mosaic of dithered optical images, but
> does much more than you probably need. --Wayne
Dear Dick,
along the lines of what Wayne said you might also consider using the TERAPIX
package (terapix.iap.fr). While the astrometry.net code establishes astrometry
for each tile blindly (provided there is a sufficient number of stars in the
field) the TERAPIX-SCAMP procedure makes use of the FITS header astrometric
info. Unlike the astrometry.net code SCAMP does not require to store several
Gigabyte of precooked astrometric indices locally but retrieves catalog entries
from CDS. I have given up my own IDL mosaic routine in favor of TERAPIX for the
processing of the Tautenburg Schmidt frames (using an IDL wrapper script).
Regards,
Bringfried
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
