MOPEX User's Guide - IRSA

DISCUSSION
MOPEX User’s Guide
For complete instructions on how to use this module to create a mosaic of a subset of a larger
dataset, please see §5.3: Mosaicking a Portion of the Total FIF. This includes information on
how to modify the FIF.tbl file to specify the new area.
5.6.6 Mosaic Modules: MedFilter
Command Line Equivalent: run_medfilter
Default Output Directory: /Medfilter-mosaic
De pe nds On: Initial Setup; Mosaic Settings
PURPOSE
This module performs a background subtraction of the individual input images. It needs to
run if single-frame outlier rejection or dual outlier rejection are to be used in the Mosaic
pipeline (see §8.2.1; §8.2.3). There are two options: the Median case (default) and the Sbkg
case, which uses a background estimate like that of SExtractor.
INPUT
Window X, Y: (int) the X, Y size in input pixels of the window used to compute the
background value.
Outlie rs / Window: (int) the number of high outlier pixels rejected from the X*Y window
when computing the Median background. For a very crowded field, the fraction of rejected
pixels should be higher than for a less crowded field. Values of a few percent should be
acceptable for uncrowded fields. If Outliers / Window is set too high, the background will be
under-estimated.
SExtractor background filter size: (int) Median filter box size for the Panels when the Use
SExtractor background estimation option is turned on. A value less than 2 means no filtering.
If greater than the minimum number of panels across an image, it will use the minimum.
Use SExtractor background estimation: Checking this box invokes the Sbkg background
estimate based on SExtractor. Leaving it unchecked causes MOPEX to use the default
Median estimate.
Mosaicking (mosaic.pl) 61
Mosaic Modules