CpCtiSolveTask#

class lsst.cp.pipe.CpCtiSolveTask(**kwargs)#

Bases: PipelineTask

Combine CTI measurements to a final calibration.

This task uses the extended pixel edge response (EPER) method as described by Snyder et al. 2021, Journal of Astronimcal Telescopes, Instruments, and Systems, 7, 048002. doi:10.1117/1.JATIS.7.4.048002

Methods Summary

calcCtiTurnoff(signalVec, dataVec, ctiRange, amp)

Solve for turnoff value in a sequenced dataset.

calcEper(mode, inputMeasurements, amp)

Solve for serial or parallel global CTI using the extended pixel edge response (EPER) method.

debugView(ampName, signal, test)

Debug method for global CTI test value.

findTraps(inputMeasurements, calib, detector)

Solve for serial trap parameters.

run(inputMeasurements, camera, inputDims, ...)

Solve for charge transfer inefficiency from overscan measurements.

runQuantum(butlerQC, inputRefs, outputRefs)

Do butler IO and transform to provide in memory objects for tasks run method.

solveEper(inputMeasurements, calib, detector)

Solve for serial and parallel extended pixel edge response (EPER), which is an esimator of CTI defined in Snyder et al. 2021.

solveGlobalCti(inputMeasurements, calib, ...)

Solve for global CTI constant.

solveLocalOffsets(inputMeasurements, calib, ...)

Solve for local (pixel-to-pixel) electronic offsets.

Methods Documentation

calcCtiTurnoff(signalVec, dataVec, ctiRange, amp)#

Solve for turnoff value in a sequenced dataset.

Parameters#

signalVecnp.ndarray

Signal values for the dataset. Must be sorted in ascending order.

dataVecnp.ndarray

Data values for the dataset. Must be sorted in ascending order.

ctiRangelist [float]

Range of CTI within which to search for the turnoff point.

Returns#

turnofffloat

The turnoff point in the same units as the input signals

turnoffSamplingErrorfloat

The sampling error of the turnoff point, equals turnoff when not enough data points.

Notes#

If the data is sparse and does not cover the turnoff region, it will likely just return the highest signal in the dataset.

However, it will issue a warning if the turnoff point is at the edge of the search range.

calcEper(mode, inputMeasurements, amp)#

Solve for serial or parallel global CTI using the extended pixel edge response (EPER) method.

Parameters#

modestr

The orientation of the calculation to perform. Can be either “SERIAL” or “PARALLEL”.

inputMeasurementslist [dict]

List of overscan measurements from each input exposure. Each dictionary is nested within a top level “CTI” key, with measurements organized by amplifier name, containing keys:

"FIRST_COLUMN_MEAN"

Mean value of first image column (float).

"LAST_COLUMN_MEAN"

Mean value of last image column (float).

"IMAGE_MEAN"

Mean value of the entire image region (float).

"SERIAL_OVERSCAN_COLUMNS"

List of serial overscan column indicies (list [int]).

"SERIAL_OVERSCAN_VALUES"

List of serial overscan column means (list [float]).

"PARALLEL_OVERSCAN_ROWS"

List of parallel overscan row indicies (list [int]).

"PARALLEL_OVERSCAN_VALUES"

List of parallel overscan row means (list [float]).

caliblsst.ip.isr.DeferredChargeCalib

Calibration to populate with values.

amplsst.afw.cameraGeom.Amplifier

Amplifier object containing the geometry information for the amplifier.

Returns#

caliblsst.ip.isr.DeferredChargeCalib

Populated calibration.

Raises#

RuntimeErrorRaised if no data remains after flux filtering or if

the mode string is not one of “SERIAL” or “PARALLEL”.

debugView(ampName, signal, test)#

Debug method for global CTI test value.

Parameters#

ampNamestr

Name of the amp for plot title.

signallist [float]

Image means for the input exposures.

testlist [float]

CTI test value to plot.

findTraps(inputMeasurements, calib, detector)#

Solve for serial trap parameters.

Parameters#

inputMeasurementslist [dict]

List of overscan measurements from each input exposure. Each dictionary is nested within a top level “CTI” key, with measurements organized by amplifier name, containing keys:

"FIRST_COLUMN_MEAN"

Mean value of first image column (float).

"LAST_COLUMN_MEAN"

Mean value of last image column (float).

"IMAGE_MEAN"

Mean value of the entire image region (float).

"SERIAL_OVERSCAN_COLUMNS"

List of overscan column indicies (list [int]).

"SERIAL_OVERSCAN_VALUES"

List of overscan column means (list [float]).

caliblsst.ip.isr.DeferredChargeCalib

Calibration to populate with values.

detectorlsst.afw.cameraGeom.Detector

Detector object containing the geometry information for the amplifiers.

Returns#

caliblsst.ip.isr.DeferredChargeCalib

Populated calibration.

Raises#

RuntimeError

Raised if no data remains after flux filtering.

Notes#

The original CTISIM code uses a data model in which the “overscan” consists of the standard serial overscan bbox with the values for the last imaging data column prepended to that list. This version of the code keeps the overscan and imaging sections separate, and so a -1 offset is needed to ensure that the same columns are used for fitting between this code and CTISIM. This offset removes that last imaging data column from the count.

run(inputMeasurements, camera, inputDims, linearizer)#

Solve for charge transfer inefficiency from overscan measurements.

Parameters#

inputMeasurementslist [dict]

List of overscan measurements from each input exposure. Each dictionary is nested within a top level “CTI” key, with measurements organized by amplifier name, containing keys:

"FIRST_COLUMN_MEAN"

Mean value of first image column (float).

"LAST_COLUMN_MEAN"

Mean value of last image column (float).

"IMAGE_MEAN"

Mean value of the entire image region (float).

"SERIAL_OVERSCAN_COLUMNS"

List of overscan column indicies (list [int]).

"SERIAL_OVERSCAN_VALUES"

List of overscan column means (list [float]).

"PARALLEL_OVERSCAN_ROWS"

List of overscan row indicies (list [int]).

"PARALLEL_OVERSCAN_VALUES"

List of overscan row means (list [float).

"INPUT_GAIN"

The gains used to convert the image to electrons before calculating CTI statistics. (float).

cameralsst.afw.cameraGeom.Camera

Camera geometry to use to find detectors.

inputDimslist [dict]

List of input dimensions from each input exposure.

linearizerlsst.ip.isr.Linearizer

Input linearizer. Used for metadata inheritance.

Returns#

resultslsst.pipe.base.Struct

Result struct containing:

outputCalib

Final CTI calibration data (lsst.ip.isr.DeferredChargeCalib).

Raises#

RuntimeError

Raised if data from multiple detectors are passed in.

runQuantum(butlerQC, inputRefs, outputRefs)#

Do butler IO and transform to provide in memory objects for tasks run method.

Parameters#

butlerQCQuantumContext

A butler which is specialized to operate in the context of a lsst.daf.butler.Quantum.

inputRefsInputQuantizedConnection

Datastructure whose attribute names are the names that identify connections defined in corresponding PipelineTaskConnections class. The values of these attributes are the lsst.daf.butler.DatasetRef objects associated with the defined input/prerequisite connections.

outputRefsOutputQuantizedConnection

Datastructure whose attribute names are the names that identify connections defined in corresponding PipelineTaskConnections class. The values of these attributes are the lsst.daf.butler.DatasetRef objects associated with the defined output connections.

solveEper(inputMeasurements, calib, detector)#

Solve for serial and parallel extended pixel edge response (EPER), which is an esimator of CTI defined in Snyder et al. 2021.

Parameters#

inputMeasurementslist [dict]

List of overscan measurements from each input exposure. Each dictionary is nested within a top level “CTI” key, with measurements organized by amplifier name, containing keys:

"FIRST_COLUMN_MEAN"

Mean value of first image column (float).

"LAST_COLUMN_MEAN"

Mean value of last image column (float).

"IMAGE_MEAN"

Mean value of the entire image region (float).

"SERIAL_OVERSCAN_COLUMNS"

List of overscan column indicies (list [int]).

"SERIAL_OVERSCAN_VALUES"

List of overscan column means (list [float]).

"PARALLEL_OVERSCAN_ROWS"

List of overscan row indicies (list [int]).

"PARALLEL_OVERSCAN_VALUES"

List of overscan row means (list [float).

caliblsst.ip.isr.DeferredChargeCalib

Calibration to populate with values.

detectorlsst.afw.cameraGeom.Detector

Detector object containing the geometry information for the amplifiers.

Returns#

caliblsst.ip.isr.DeferredChargeCalib

Populated calibration.

Notes#

The original CTISIM code uses a data model in which the “overscan” consists of the standard serial overscan bbox with the values for the last imaging data column prepended to that list. This version of the code keeps the overscan and imaging sections separate, and so a -1 offset is needed to ensure that the same columns are used for fitting between this code and CTISIM. This offset removes that last imaging data column from the count.

solveGlobalCti(inputMeasurements, calib, detector)#

Solve for global CTI constant.

This method solves for the mean global CTI, b.

Parameters#

inputMeasurementslist [dict]

List of overscan measurements from each input exposure. Each dictionary is nested within a top level “CTI” key, with measurements organized by amplifier name, containing keys:

"FIRST_COLUMN_MEAN"

Mean value of first image column (float).

"LAST_COLUMN_MEAN"

Mean value of last image column (float).

"IMAGE_MEAN"

Mean value of the entire image region (float).

"SERIAL_OVERSCAN_COLUMNS"

List of overscan column indicies (list [int]).

"SERIAL_OVERSCAN_VALUES"

List of overscan column means (list [float]).

"PARALLEL_OVERSCAN_ROWS"

List of overscan row indicies (list [int]).

"PARALLEL_OVERSCAN_VALUES"

List of overscan row means (list [float).

caliblsst.ip.isr.DeferredChargeCalib

Calibration to populate with values.

detectorlsst.afw.cameraGeom.Detector

Detector object containing the geometry information for the amplifiers.

Returns#

caliblsst.ip.isr.DeferredChargeCalib

Populated calibration.

Raises#

RuntimeError

Raised if no data remains after flux filtering.

Notes#

The original CTISIM code uses a data model in which the “overscan” consists of the standard serial overscan bbox with the values for the last imaging data column prepended to that list. This version of the code keeps the overscan and imaging sections separate, and so a -1 offset is needed to ensure that the same columns are used for fitting between this code and CTISIM. This offset removes that last imaging data column from the count.

solveLocalOffsets(inputMeasurements, calib, detector)#

Solve for local (pixel-to-pixel) electronic offsets.

This method fits for au_L, the local electronic offset decay time constant, and A_L, the local electronic offset constant of proportionality.

Parameters#

inputMeasurementslist [dict]

List of overscan measurements from each input exposure. Each dictionary is nested within a top level “CTI” key, with measurements organized by amplifier name, containing keys:

"FIRST_COLUMN_MEAN"

Mean value of first image column (float).

"LAST_COLUMN_MEAN"

Mean value of last image column (float).

"IMAGE_MEAN"

Mean value of the entire image region (float).

"SERIAL_OVERSCAN_COLUMNS"

List of overscan column indicies (list [int]).

"SERIAL_OVERSCAN_VALUES"

List of overscan column means (list [float]).

"PARALLEL_OVERSCAN_ROWS"

List of overscan row indicies (list [int]).

"PARALLEL_OVERSCAN_VALUES"

List of overscan row means (list [float).

caliblsst.ip.isr.DeferredChargeCalib

Calibration to populate with values.

detectorlsst.afw.cameraGeom.Detector

Detector object containing the geometry information for the amplifiers.

Returns#

caliblsst.ip.isr.DeferredChargeCalib

Populated calibration.

Raises#

RuntimeError

Raised if no data remains after flux filtering.

Notes#

The original CTISIM code (Snyder005/ctisim) uses a data model in which the “overscan” consists of the standard serial overscan bbox with the values for the last imaging data column prepended to that list. This version of the code keeps the overscan and imaging sections separate, and so a -1 offset is needed to ensure that the same columns are used for fitting between this code and CTISIM. This offset removes that last imaging data column from the count.