| Re: mosaic routine? [message #64436] |
Sun, 28 December 2008 18:54 |
Loren Anderson
Messages: 22
Registered: August 2007
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Junior Member |
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I have found that the Montage software (http://
montage.ipac.caltech.edu/) is extremely accurate for mosaicking
tiles. It is quite slow though for images with lots of pixels, and a
little confusing when you are first starting to use it. Still, I have
found that it produces high quality results, and is my software of
choice for such projects.
-Loren
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| Re: mosaic routine? [message #64446 is a reply to message #64436] |
Sat, 27 December 2008 01:23  |
Bringfried Stecklum
Messages: 75
Registered: January 1996
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Member |
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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
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| Re: mosaic routine? [message #64448 is a reply to message #64446] |
Fri, 26 December 2008 12:12 |
wlandsman
Messages: 743
Registered: June 2000
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Senior Member |
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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
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