QC documentation system: QC procedure QCocam_bias.py for OMEGACAM

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QCocam_qcheck.py QCocam_shutter.py QCocam_readnoise.py QCocam_lingain.py
QCocam_bias.py QCocam_dark.py QCocam_dome.py QCocam_flat.py
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NAME QCocam_bias.py
VERSION 1.0 -- 2012-06-10 First draft of this QC report
SYNTAX Python
CALL measureQuality of data contained in $DFS_PRODUCT/BIAS/$DATE
within processQC: processQC -a $AB
explicit call: QCocam_bias.py -a [$AB_name] -e [$ext_number: 1-32] -i [$level_of_interaction: 0-2]
INSTRUMENT OMEGACAM
RAWTYPE BIAS (DPR.TYPE = BIAS)
PURPOSE a) generates 2 QC reports for each OmegaCAM CCD
b) writes QC1 parameters into local QC1 database omegacam_bias
PROCINPUT No input is required:
a) $DATE is read from AB
b) the primary file is set in QCocam_bias.py and is the PRO.CATG=MASTER_BIAS product with the _0000.fits extension.
c) raw frames are implicitly read from the AB.
d) All reference products: MASTER_BIAS and HOT_PIXELS_MAP, are found and read in from $DFO_ROOT_DIR_FC/calib/references/BIAS/.
QC1TABLE trending | table(s) in QC1 database:
omegacam_bias
TRENDPLOT trending | HealthCheck plot(s) associated to this procedure:
trend_report_BIAS_level_HC.html
QC1PAGE trending | associated documentation:
bias_QC1.html
QC1PLOTS
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bias1.png
display each of 32 MASTER_BIAS frames on ds9 display.

bias2.png
display each of 32 HOT_PIXELS_MAP frames on ds9 display. Note that hot pixels have a value of 1. Normal pixels = 0.

bias3.png
left: full-field image of the master bias of the extension listed at the top of the image
center left: 4x zoom of the center area of the master bias
center right: the difference of the reference master bias and the current master bias frames.
The median level of the difference image is listed to the right of the frame.
right: full-field image of the hot pixels map. The positions of the reference frame hot pixels are shown
in red, while the hot pixels of the current bias frame are shown in blue. The total numbers of hot pixels are listed
in the frame legend.

bias4.png
top left: a) three single column traces of the current/reference master bias through:
x = 256 (dark grey)
x = 1024 (middle grey)
x = 1792 (light grey)
b) average of all columns (normalized) of current master bias (thick blue line)
c) average of all columns (normalized) of reference master bias (thick red line)
top center: a) three single row traces of the current/reference master bias through:
y = 256 (dark grey)
y = 2048 (middle grey)
y = 3840 (light grey)
b) average of all rows (normalized) of current master bias (thick blue line)
c) average of all rows (normalized) of reference master bias (thick red line)
top right: a) logarithmic histogram of current master bias (blue line)
b) logarithmic histogram of reference master bias (red line)
The median levels (as computed from a Gaussian fit) are shown as vertical dashed lines and listed in the legend.
lower left: difference between the average column traces of the reference and current master bias frames
lower center: difference between the average row traces of the reference and current master bias frames
In both plots, the zero line is shown in orange as a reference.
lower right: logarithmic histogram of the difference between the reference and current master bias frames.
Ideally, the histogram should straddle the zero line (shown in orange).
The median difference (as computed from a Gaussian fit) is shown as vertical dashed green line.
QC1PARAM QC1 parameters written into QC1 table(omegacam_bias) 
SOURCE(header or script)   DBNAME                  value       description

 PRO.DATANCOM              datancom                10          number of raw files combined in pipeline processing
 QC.MASTER.BIAS.MEDIAN     qc_bias_median          276.455     median value of master bias frame (ADU)
 QC.MASTER.BIAS.STDEV      qc_bias_std             0.8692      standard deviation of master bias frame (ADU)
 QC.NUMBER.HOT.PIXELS      qc_bias_hotpixels       98          number of hot pixels in master bias frame
 QCocam_bias.py            qc_temp_mosaic_plate    146.5       average temperature probe of mosaic plates from DET.TLM5/8 (QC script)
 QCocam_bias.py            qc_fpn                  -0.0043421  fixed pattern noise in master bias (ADU) (QC script)
 QCocam_bias.py            qc_delta_bias_median    1.45        median difference of reference - current master bias (ADU) (QC script)
 QCocam_bias.py            qc_delta_bias_hotpixels 15          difference in no. of hot pixels: reference - current master bias (QC script)
 QCocam_bias.py            qc_delta_bias_fpn       0.0012581   difference in fpn: reference - current master bias (ADU) (QC script)
ALGORITHM Description of algorithms:
qc_bias_median: the master bias frame is created from 10 input, zero-second bias exposures, averaged together with a 5sigma rejection of outliers (where sigma is defined from the dispersion of each pixel through the 10 input frames). This QC parameter is the median level of this master bias frame.
qc_bias_std: the standard deviation of the master bias frame.
qc_bias_hotpixels the number of hot pixels in the master bias frame.
qc_fpn: a central region [{100, 100)-->(1948, 4000)] of the master bias frame is defined, shifted by 10 pixels in both x and y, and subtracted from itself. The statistics of the difference image determines the fixed pattern noise.
qc_delta_bias_median: median difference of reference - current master bias (ADU).
qc_delta_bias_hotpixels: the difference in the number of hot pixels between the reference and current master bias frames.
qc_delta_bias_fpn: the difference in fixed-pattern-noise between the reference and current master bias frames.
CERTIF - The master bias frames from detectors ESO_CCD_#68 and #90 have a pronounced central ridge. This is stable and can be well subtracted. Therefore, these features are tolerated, but can create a larger number of hot pixels when compared to other detectors.
- A sudden change in the bias level of any detector, or the presence of pronounced structure should be reported to Paranal and the master bias rejected.
COMMENTS OmegaCAM bias frames are normally taken daily and consist of 10 raw, zero-second exposures.
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