CALPRODUCT-NI-001: NISP Bad Pixel Map¶
Parent requirement¶
R-NIP-P-006 in the PERD
Scheduling¶
Continuously updated.
Time-critical¶
No.
Dependencies¶
CALPRODUCT-NI-006: NISP Dark Current
Objective¶
The purpose of this task is to update the bad pixel map (BPM) on a regular basis. There is no dedicated set of observations associated with this task. The bad pixel map is derived from secondary CalProducts, obtained both on-ground (e.g. permanently disconnected pixels) and in-flight. Both intermittent and permanent bad pixels enter the BPM.
Currently, the BPM is based on the baseline maps, dark current and flat field. New dead pixels, high/low baseline, and permanently hot pixels will be identified in CALPRODUCT-NI-006: NISP Dark Current. Monitoring for bad pixels can also be done using CALPRODUCT-NI-014: NISP Slew Darks. In total, there are 5 PEs that currently build the BPM. A robust definition of hot pixels is still pending.
Snowballs inject a lot of energy; some are recurrent, others are randomly distributed. There is currently no calibration product for them.
Random telegraph noise (RTN) pixels can be identified in flat fields, but are currently not covered by processing.
Anomalous nonlinearity and high persistence are currently not entering the BPM. Pixels that currently carry a persistence signal are masked anyway during the survey if beyond a threshold.
Fulfilled by¶
Different data products contribute to the bad-pixel map.
CALBLOCK-PV-010: NISP LED flats
CALBLOCK-PV-012: NISP Dark Current and Snowballs
CALBLOCK-PV-014: NISP Baseline Map
CALBLOCK-F-006: Wide Survey (providing the slew darks)
CALBLOCK-F-007: VIS Nonlinearity, PTC, BFE and NISP LED flats
Instrument configuration¶
Instrument: NISP
Processing input¶
Static bad pixel map (dead, disconnected, hot)
Dark current map (warm and hot pixels)
Baseline map (pixels with limited dynamic range due to high bias level)
LED flat fields
Pixels with high random telegraph noise (RTN, currently not captured).
Ground Processing Input Data: Dark, nonlinearity, small-scale flat, persistence map, static bad pixel map
Data Description:
Processing output¶
Updated BPM. Monitoring of the total fraction of bad pixels, as well as the fractions of the individual contributors.
Validation¶
R-NIP-P-006 and R-NIS-P-016 in EUCL-EST-RD-3-002_v2.2_PERD (PERD) allow a lost pixel budget of 10%. Internally, this is broken down into transients (3% for cosmics, 1% for persistence from previous exposures), 5% for static and dynamic bad pixels, and 1% margin.
The BPM of this CalProduct concerns about the static and dynamic bad pixels, only. The BPM shall not mask more than 5% of all pixels.
Recovery¶
If more than 5% of pixels are masked by the BPM, the underlying contributors and causes shall be identified. We highlight two possible scenarious:
First, a single CalProduct entering the BPM causes excess masking. This could indicate a failure
in the validation of that specific CalProduct. The validation criteria, monitoring analysis and thresholding of this CalProduct must be revisited. For example, it might have been taken during increased solar proton flux levels, and an adjustment of the allowed threshold is required or a change of procedures in order. The invalid CalProduct shall be replaced by a previous, valid version.
Second, several CalProducts contribute increased amounts of bad pixels, none of them individually at a level that would raise a concern during its validation. This could happen e.g. towards the end of the mission, when radiation damages accumulate.
Quality control parameters¶
DataModel: https://gitlab.euclid-sgs.uk/
Contact person¶
NISP-P calibration scientist