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• See Module ImgAlgos::NDArrAverage andModule CSPadPixCoords::CSPadNDArrProducer

• The NDArrAverage module in combination with CSPadNDArrProducer (or any other device NDArrProducer) can be used for evaluation of averaged pedestals or background using dedicated runs.
  Typical configuration file may looks like this:

  No Format

  # Run this script: # psana -c psana-meca1113-r0045-cspad-cspad-dark-hotpix.cfg [psana] files = exp=meca1113:run=45 events = 400 #skip-events = 0 modules = CSPadPixCoords.CSPadNDArrProducer \ ImgAlgos.NDArrAverage \ ImgAlgos.Tahometer [CSPadPixCoords.CSPadNDArrProducer] source = MecTargetChamber.0:Cspad.0 inkey = outkey = cspad_ndarr outtype = int16 is_fullsize = yes print_bits = 3 [ImgAlgos.NDArrAverage] source = MecTargetChamber.0:Cspad.0 key = cspad_ndarr avefile = cspad.0-ave rmsfile = cspad.0-rms maskfile = cspad.0-msk hotpixfile = cspad.0-hot thr_rms_ADU = 10 thr_min_ADU = 4 thr_max_ADU = 10000 print_bits = 29 #evts_stage1 = 100 #gate_width1 = 500. #evts_stage2 = 200 #gate_width2 = 100. [ImgAlgos.Tahometer] dn = 100 print_bits = 7

• Module ImgAlgos.Tahometer is not required in this configuration file and is added for convenience to print timing statistics for this job.
• Evaluation of average intensity in 2 or 3 stages using gate-based algorithms excludes out-layers in intensity spectra and makes average more stable and reliable. However, the gate width is not a an universal parameter. In order to set this parameter one has to look at spectrum of averaged intensities for particular device.  The same is valid for evaluation of hot/bad pixel masks. One has to plot spectra of averaged intensity and rms values. Averaged intensity and rms spectra for exp=meca1113:run=45 are shown on plots, respectively:

Then, one has to decide how to set parameters for NDArrAverage algorithms, for example, it is quite save safe to use

• thr_rms_ADU = 10  – to discard very noisy pixels,
• thr_min_ADU = 4  – to discard presumably dead pixels with 0-intensity,
• thr_max_ADU = 10000 – to discard pixels with intensity significantly exceeding average value. To be on safe side for int16 data this parameter can be set to 2¹⁶-4, where 4 in both cases is just a small arbitrary number for spare safety gap.

Example for module ImgAlgos::ImgAverage

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