Mitigate IR Persistence

This algorithm generates a map of the persistence present in an infra- red detector due to charge trapped in the depletion regions of each pixel left over from previous exposures. Excess flux from this source may then be corrected for by subtracting off the persistence map. More...

Functions
cpl_error_code	hdrl_persistence_compute (const double gain, const double turnover, const double mean_trim, const cpl_boolean cleanQ, const cpl_array *dateobs, const cpl_array *exptimes, hdrl_imagelist *ilist_persistence, const cpl_imagelist *ilist_obj, const cpl_image *maximum, const cpl_image *density, const cpl_image *fullwell, const cpl_table *frac, hdrl_image **persistence, cpl_propertylist **persistence_qc)
	generate the persistence map

Detailed Description

This algorithm generates a map of the persistence present in an infra- red detector due to charge trapped in the depletion regions of each pixel left over from previous exposures. Excess flux from this source may then be corrected for by subtracting off the persistence map.

Characterisation work performed by the ESO Detector Systems Group has resulted in a predictive model using a 5th order IIR filter, where each pole/order of the filter represents a different detrapping time constant bin. The sum of the 5 exponential functions produces the de- trapped charge profile, or the flux due to persistence. The algorithm in this file implements this model.

For more details on the algorithm/model, or the characterisation of the time constants, please refer to: SPIE Journal Paper | September 3, 2019 Predictive model of persistence in H2RG detectors Simon Tulloch; Elizabeth George; ESO Detector Systems Group JATIS Vol. 5 Issue 03

Generate a persistence map from previous illumination frames, a trap

density map and RHO values for each detrap time constant (TAU), and source maps derived from the illumination frames. The trap density map (TDM) and RHO values are specific to the IR detector in question.

Function Documentation

hdrl_persistence_compute()

cpl_error_code hdrl_persistence_compute	(	const double	gain,
		const double	turnover,
		const double	mean_trim,
		const cpl_boolean	cleanQ,
		const cpl_array *	dateobs,
		const cpl_array *	exptimes,
		hdrl_imagelist *	ilist_persistence,
		const cpl_imagelist *	ilist_obj,
		const cpl_image *	maximum,
		const cpl_image *	density,
		const cpl_image *	fullwell,
		const cpl_table *	frac,
		hdrl_image **	persistence,
		cpl_propertylist **	persistence_qc
	)

generate the persistence map

Parameters

gain	The gain for ADU to electron conversion [e-/ADU]
turnover	The detector turnover value [ADU]
mean_trim	The percentage of the pixels to discard in the minmax based QC parameter
cleanQ	Whether or not to filter individual Qi planes
dateobs	The times when the data is taken, e.g. MJD-OBS (including the MJD-OBS of the target frame)
exptimes	The exposure sequence times of the data, e.g. EXPTIME (excluding the EXPTIME of the target frame)[s]
ilist_persistence	Imagelist containing the images causing the persistence [ADU]
ilist_obj	Masks with the objects of the single images (or NULL)
maximum	A two-dimensional map describing the maximum number of persistence traps in each pixel [number]
density	A two-dimensional map describing the fraction of incident photons that get converted to traps [unitless]
fullwell	A two-dimensional map describing the full-well capacity of each pixel [ADU]
frac	A table containing a six-term vector describing the relative fraction of each time constant populated by each trap [unitless]
persistence	Returned: the calculated persistence [e-]
persistence_qc	Returned: QC parameters derived from the calculated persistence

Returns

The cpl error code in case of error or CPL_ERROR_NONE