Provided by: montage_6.0+dfsg-6_amd64
mDiff - Calculates the difference between a pair of overlapping images
mDiff [-d level] [-n(o-areas)] [-s statusfile] in1.fits in2.fits out.fits template.hdr
mDiff calculates a simple difference between a single pair of overlapping images. This is meant for use on reprojected images where the pixels already line up exactly. mDiff analyzes an image metadata table to determine a list of overlapping images. Each image is compared with every other image to determine all overlapping image pairs. A pair of images are deemed to overlap if any pixel around the perimeter of one image falls within the boundary of the other image.
-d level Turns on debugging to the specified level (1-4). -n No-area-images flag. Creates difference image without requiring pixel area FITS image -z factor Scale second image by factor before subtracting. -s statusfile Output and errors are sent to statusfile instead of to stdout
in1.fits First input FITS file. (Also needs area image in1_area.fits, or use -n flag) in2.fits Second input FITS file.(Also needs area image in2_area.fits, or use -n flag) out.fits Difference FITS image to be generated. template.hdr FITS header template used to generate output image.
FITS image and area image representing the difference in the overlap region.
OK [struct stat="OK"] ERROR Cannot open status file: statusfile ERROR Images don't overlap ERROR All pixels are blank ERROR Template file not found ERROR FITS library error ERROR general error
$ mDiff proj/in1.fits proj/in2.fits output/diff.fits template.hdr [struct stat="OK"]
The drizzle algorithm has been implemented but has not been tested in this release. If a header template contains carriage returns (i.e., created/modified on a Windows machine), the cfitsio library will be unable to read it properly, resulting in the error: [struct stat="ERROR", status=207, msg="illegal character in keyword"] It is best for the background correction algorithms if the area described in the header template completely encloses all of the input images in their entirety. If parts of input images are "chopped off" by the header template, the background correction will be affected. We recommend you use an expanded header for the reprojection and background modeling steps, returning to the originally desired header size for the final coaddition. The default background matching assumes that there are no non-linear background variations in the individual images (and therefore in the overlap differences). If there is any uncertainty in this regard, it is safer to turn on the "level only" background matching (the "-l" flag in mBgModel.
2001-2015 California Institute of Technology, Pasadena, California If your research uses Montage, please include the following acknowledgement: "This research made use of Montage. It is funded by the National Science Foundation under Grant Number ACI-1440620, and was previously funded by the National Aeronautics and Space Administration's Earth Science Technology Office, Computation Technologies Project, under Cooperative Agreement Number NCC5-626 between NASA and the California Institute of Technology." The Montage distribution includes an adaptation of the MOPEX algorithm developed at the Spitzer Science Center.