CalibrateTask

class lsst.pipe.tasks.calibrate.CalibrateTask(astromRefObjLoader=None, photoRefObjLoader=None, icSourceSchema=None, initInputs=None, **kwargs)

Bases: PipelineTask

Calibrate an exposure: measure sources and perform astrometric and photometric calibration.

Given an exposure with a good PSF model and aperture correction map(e.g. as provided by CharacterizeImageTask), perform the following operations: - Run detection and measurement - Run astrometry subtask to fit an improved WCS - Run photoCal subtask to fit the exposure’s photometric zero-point

Parameters

butlerNone

Compatibility parameter. Should always be None.

astromRefObjLoaderlsst.meas.algorithms.ReferenceObjectLoader, optional

Unused in gen3: must be None.

photoRefObjLoaderlsst.meas.algorithms.ReferenceObjectLoader, optional

Unused in gen3: must be None.

icSourceSchemalsst.afw.table.Schema, optional

Schema for the icSource catalog.

initInputsdict, optional

Dictionary that can contain a key icSourceSchema containing the input schema. If present will override the value of icSourceSchema.

Raises

RuntimeError

Raised if any of the following occur: - isSourceCat is missing fields specified in icSourceFieldsToCopy. - PipelineTask form of this task is initialized with reference object

loaders.

Notes

Quantities set in exposure Metadata:

MAGZERO_RMS

MAGZERO’s RMS == sigma reported by photoCal task

MAGZERO_NOBJ

Number of stars used == ngood reported by photoCal task

COLORTERM1

?? (always 0.0)

COLORTERM2

?? (always 0.0)

COLORTERM3

?? (always 0.0)

Debugging: CalibrateTask has a debug dictionary containing one key:

calibrate

frame (an int; <= 0 to not display) in which to display the exposure, sources and matches. See @ref lsst.meas.astrom.displayAstrometry for the meaning of the various symbols.

Methods Summary

copyCalibSourceFields(calibType, ...)	Match sources in a calibrationCat and a sourceCat and copy fields.
recordMaskedPixelFractions(exposure)	Record the fraction of all the pixels in an exposure that are masked with a given flag.
run(exposure[, background, icSourceCat, ...])	Calibrate an exposure.
runQuantum(butlerQC, inputRefs, outputRefs)	Do butler IO and transform to provide in memory objects for tasks run method.
setMetadata(exposure[, photoRes])	Set task and exposure metadata.

Methods Documentation

copyCalibSourceFields(calibType, schemaMapper, calibCat, sourceCat, fieldsToCopy)

Match sources in a calibrationCat and a sourceCat and copy fields.

The fields copied are those specified by config.icSourceFieldsToCopy if calibType is icSource or config.astromFieldsToCopy if calibType is astrometry.

Parameters

calibTypestr

The type of calibration: either icSource or astrometry.

calibCatlsst.afw.table.SourceCatalog

Catalog from which to copy fields.

sourceCatlsst.afw.table.SourceCatalog

Catalog to which to copy fields.

Raises

RuntimeError

Raised if any of the following occur: - calibSchema and calibSourceKeys are not specified. - calibCat and sourceCat are not specified. - calibFieldsToCopy is empty.

recordMaskedPixelFractions(exposure)

Record the fraction of all the pixels in an exposure that are masked with a given flag. Each fraction is recorded in the task metadata. One record per flag type.

Parameters

exposurelsst.afw.image.ExposureF

The target exposure to calculate masked pixel fractions for.

run(exposure, background=None, icSourceCat=None, idGenerator=None)

Calibrate an exposure.

Parameters

exposurelsst.afw.image.ExposureF

Exposure to calibrate.

backgroundlsst.afw.math.BackgroundList, optional

Initial model of background already subtracted from exposure.

icSourceCatlsst.afw.image.SourceCatalog, optional

SourceCatalog from CharacterizeImageTask from which we can copy some fields.

idGeneratorlsst.meas.base.IdGenerator, optional

Object that generates source IDs and provides RNG seeds.

Returns

resultlsst.pipe.base.Struct

Results as a struct with attributes:

exposure

Characterized exposure (lsst.afw.image.ExposureF).

sourceCat

Detected sources (lsst.afw.table.SourceCatalog).

outputBackground

Model of subtracted background (lsst.afw.math.BackgroundList).

astromMatches

List of source/ref matches from astrometry solver.

matchMeta

Metadata from astrometry matches.

outputExposure

Another reference to exposure for compatibility.

outputCat

Another reference to sourceCat for compatibility.

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.

setMetadata(exposure, photoRes=None)

Set task and exposure metadata.

Logs a warning continues if needed data is missing.

Parameters

exposurelsst.afw.image.ExposureF

Exposure to set metadata on.

photoReslsst.pipe.base.Struct, optional

Result of running photoCal task.