Depends On: Mosaic Interpolate (or Mosaic Reinterpolate)
PURPOSE
After all outlier pixels have been identified in the previous modules, there is the option to suppress usage of pixels that have very small coverage (number of repeated observations at the same point of sky). Pixels whose usage is suppressed have their coverage set to 0 in new coverage maps.
INPUT
Min Single Coverage: (float) The minimum coverage for an individual pixel. The default value is 0.95.
Min Block Coverage: (float) The minimum average coverage in the block of 9 pixels centered on a given pixel for it to be retained. The default value is 0.83
COMMAND LINE INPUT
Within mosaic.pl, no parameters are set for this module, so default values are used for Min Single Coverage and Min Block Coverage
OUTPUT
Fix Coverage Images (fixed_covg_*.fits): The stack of corrected coverage maps.
DISCUSSION
Two thresholds are used for each coverage map pixel, one - Min Single Coverage - for the pixel value alone and the other one - Min Block Coverage - for the sum of the values of the block of 9 pixels centered on the pixel in question (see Figure 5.1 below). The following logic is used:
IF C5 < Min Single Coverage THEN C5 = 0;
IF (C1 + C2 + C3 + C4 + C5 + C6 + C7 + C8 + C9) < 9 * Min Block Coverage THEN C5 = 0.
Figure 5.1: Coverage for the central pixel (C5) is fixed based on the two thresholds: Min Single Coverage for C5 and Min Block Coverage for the sum of all nine Cis.
