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7.2.2 NEWSIPS Quality Flags

  For NEWSIPS, $\nu$ flags are assigned to each datum in the SI and MX files. These are negative values, as are the IUESIPS $\epsilon$ values, but instead of keeping only the ``worst'' (i.e., most negative) condition, all problems are represented. Fifteen of the 16 bits (the 16th being the negative sign) in each flag are assigned to various problem conditions (see Table 7.2). Thus if a given flag has a value of -1056, that pixel is both saturated and SWET (the extraction algorithm) found a ``cosmic ray'' there--bits 6 (-32) and 11 (-1024) are set. See the NEWSIPS Image Processing Manual for details on how the flagging is done.

Patching procedures will generally set bit 6 (-32) in the $\nu$ value for user-flagged data.

 
 
Table 7.2: NEWSIPS $\nu$ Flag Values
Condition $\nu$ Flag Value Bit
Regions not photometrically corrected -16384 15
Telemetry dropouts (missing minor frames) -8192 14
Reseaux (in the ITF) -4096 13
Permanent ITF artifacts -2048 12
Saturated Pixel (w.r.t. ITF pixel DN) -1024 11
Warning track (near edge of PHOTOM region) -512 10
Extrapolated ITF curve (above level 12) -256 9
Extrapolated ITF curve (below level 1) -128 8
Cosmic ray hits & bright spots -64 7
SWET ``cosmic rays'' -32 6
Microphonics (LWR only) -16 5
Potential DMU corrupted pixel -8 4
Telemetry dropouts in extracted background -4 3
Uncalibrated data (extracted data only) -2 2
No known problem condition    


next up previous contents
Next: 7.2.3 Unflagged Contamination Sources Up: 7.2 Contamination of Spectral Previous: 7.2.1 IUESIPS Quality Flags

2/9/1998