DeferredChargeCalib

class lsst.ip.isr.DeferredChargeCalib(**kwargs)

Bases: IsrCalib

Calibration containing deferred charge/CTI parameters.

This includes, parameters from Snyder+2021 and exstimates of the serial and parallel CTI using the extended pixel edge response (EPER) method (also defined in Snyder+2021).

Parameters

**kwargs :

Additional parameters to pass to parent constructor.

Notes

The charge transfer inefficiency attributes stored are:

driftScaledict [str, float]

A dictionary, keyed by amplifier name, of the local electronic offset drift scale parameter, A_L in Snyder+2021.

decayTimedict [str, float]

A dictionary, keyed by amplifier name, of the local electronic offset decay time, tau_L in Snyder+2021.

globalCtidict [str, float]

A dictionary, keyed by amplifier name, of the mean global CTI paramter, b in Snyder+2021.

serialTrapsdict [str, lsst.ip.isr.SerialTrap]

A dictionary, keyed by amplifier name, containing a single serial trap for each amplifier.

signalsdict [str, np.ndarray]

A dictionary, keyed by amplifier name, of the mean signal level for each input measurement.

inputGaindict [str, float]

A dictionary, keyed by amplifier name of the input gain used to calculate the overscan statistics and produce this calib.

serialEperdict [str, np.ndarray, float]

A dictionary, keyed by amplifier name, of the serial EPER estimator of serial CTI, given in a list for each input measurement.

parallelEperdict [str, np.ndarray, float]

A dictionary, keyed by amplifier name, of the parallel EPER estimator of parallel CTI, given in a list for each input measurement.

serialCtiTurnoffdict [str, float]

A dictionary, keyed by amplifier name, of the serial CTI turnoff (unit: electrons).

parallelCtiTurnoffdict [str, float]

A dictionary, keyed by amplifier name, of the parallel CTI turnoff (unit: electrons).

serialCtiTurnoffSamplingErrdict [str, float]

A dictionary, keyed by amplifier name, of the serial CTI turnoff sampling error (unit: electrons).

parallelCtiTurnoffSamplingErrdict [str, float]

A dictionary, keyed by amplifier name, of the parallel CTI turnoff sampling error (unit: electrons).

Also, the values contained in this calibration are all derived from and image and overscan in units of electron as these are the most natural units in which to compute deferred charge. However, this means the the user should supply a reliable set of gains when computing the CTI statistics during ISR.

Version 1.1 deprecates the USEGAINS attribute and standardizes

everything to electron units.

Version 1.2 adds the signal, serialEper, parallelEper,

serialCtiTurnoff, parallelCtiTurnoff, serialCtiTurnoffSamplingErr, parallelCtiTurnoffSamplingErr attributes.

Version 1.3 adds the inputGain attribute.

Methods Summary

fromDetector(detector)	Read metadata parameters from a detector.
fromDict(dictionary)	Construct a calibration from a dictionary of properties.
fromTable(tableList)	Construct calibration from a list of tables.
toDict()	Return a dictionary containing the calibration properties.
toTable()	Construct a list of tables containing the information in this calibration.

Methods Documentation

fromDetector(detector)

Read metadata parameters from a detector.

Parameters

detectorlsst.afw.cameraGeom.detector

Input detector with parameters to use.

Returns

caliblsst.ip.isr.Linearizer

The calibration constructed from the detector.

classmethod fromDict(dictionary)

Construct a calibration from a dictionary of properties.

Parameters

dictionarydict

Dictionary of properties.

Returns

caliblsst.ip.isr.CalibType

Constructed calibration.

Raises

RuntimeError

Raised if the supplied dictionary is for a different calibration.

classmethod fromTable(tableList)

Construct calibration from a list of tables.

This method uses the fromDict method to create the calibration, after constructing an appropriate dictionary from the input tables.

Parameters

tableListlist [lsst.afw.table.Table]

List of tables to use to construct the CTI calibration. Two tables are expected in this list, the first containing the per-amplifier CTI parameters, and the second containing the parameters for serial traps.

Returns

caliblsst.ip.isr.DeferredChargeCalib

The calibration defined in the tables.

Raises

ValueError

Raised if the trap type or trap coefficients are not defined properly.

toDict()

Return a dictionary containing the calibration properties. The dictionary should be able to be round-tripped through fromDict.

Returns

dictionarydict

Dictionary of properties.

toTable()

Construct a list of tables containing the information in this calibration.

The list of tables should create an identical calibration after being passed to this class’s fromTable method.

Returns

tableListlist [lsst.afw.table.Table]

List of tables containing the crosstalk calibration information. Two tables are generated for this list, the first containing the per-amplifier CTI parameters, and the second containing the parameters for serial traps.