Return to Post-BCD pages
 
Manual Contents
 
Getting Started
 
Input Files
 
Background Matching (overlap.pl)
 
Mosaicking (mosaic.pl)
 
Point Source Extraction (apex*.pl)
 
Basic Concepts
 
Appendix 1: Full List of MOPEX Scripts
 
Appendix 2: Fatal Bit Patterns
 
Appendix 3: Full Lit of MOPEX Modules

Modules: Mosaic Box Outlier

Namelist Trigger: run_mosaic_box_outlier
Output Directory Keyword: BOX_OUTLIER_DIR
Default Output Directory: <output_dir>/BoxOutlier
Depends on: Mosaic Interpolate

Important Notes: Using this module does not mean that MOPEX will automatically use the results for outlier detection. In order to use the results from this module, you must include the USE_BOX_OUTLIER_FOR_RMASK trigger in the namelist and set the RMask_Fatal_BitPattern to use bit 3. Note that this is not the same as setting it to a value of 3. See Appendix 2: Fatal Bit Patterns for more information.


PURPOSE

    This module uses the Box Outlier rejection method to flag bad pixels. The method is designed to use both the temporal and spatial information like the dual outlier, but it uses the statistical analysis of the kind used by the temporal outlier. In the identification of temporal outliers, neighboring pixels are utilized to ensure the correct classification.

PARAMETER BLOCK

    &MOSAICOUTLIERIN
     BOX_X = 3,
     BOX_Y = 3,
     BOX_MEDIAN_BIAS = 1,
     TILE_XSIZ = 500,
     TILE_YSIZ = 500,
    &END

INPUTS

    Box_X(Y): (int) the X (Y) size of the box of neighboring pixels used for outlier detections.

    BOX_MEDIAN_BIAS: : (float) The computation of the mean and sigma for each pixel stack is done using a biased median. If there are N pixels in the stack, then the biased median is equal to the N/2 - Bias element of the stack:

      biased_median(I[k]) = I[N/2 - Bias]

    TILE_X(Y)SIZ: (int) Set these to smaller numbers to avoid memory problems with dealing with a large mosaic. See the discussion of Tiles for details.

OUTPUTS

    Box Outlier Output FITS (interp_*_box_outlier.fits): The product of this step is an outlier map. The pixel value is the deviation of the pixel in the input image from the mean of that pixel in the stack, in terms of the number of sigma.


DISCUSSION

This module represents a more complicated dual spatial-temporal filtering. It extends the regular temporal outlier detection, which computes the statistics of the pixels in the stack for each mosaic pixel position, by including the pixels in the box region around that pixel in the statistics. This allows for detecting outliers even in the coverage = 2 case and at the same time provides a guard against detecting pixels inside bright point sources as outliers.



SPITZER HOME || SPITZER SCIENCE || INSTRUMENTS || SCIENCE USER SUPPORT || SEARCH

help@spitzer.caltech.edu

This file was last modified on Tue Jun 10 17:37:47 PDT 2008.

California Institute of Technology Jet Propulsion Laboratory NASA