Spitzer Documentation & Tools
MOPEX User's Guide

5.6.21    Mosaic Modules: Mosaic MedFilter

Command Line Equivalent: run_mosaic_medfilter

Default Output Directory: <output_dir>/Combine-mosaic

Depends On: Mosaic Combine

 

PURPOSE

This module uses a median filter to create a background-subtracted version of the final mosaic.

 

INPUT

Window X, Y: (int) the X, Y size in input pixels of the window used to compute the background value.

 

Outliers / 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.

 

COMMAND LINE INPUT

&MOSAIC_MEDFILTER

 Window_X = 45,

 Window_Y = 45,

 N_Outliers_Per_Window = 500,

 Sbkg_Filt_Size_for_Med = 1,

 Use_Sbkg_for_Med = 1,

&END

 

OUTPUT

Mosaic Minback file (mosaic_minback.fits): the background subtracted image saved in the output directory of Mosaic Combine.

 

DISCUSSION

This module is optional for mosaicking images. It is an optional input to APEX One Frame, if the global background subtraction option is chosen.