FinalizeCharacterizationTask

FinalizeCharacterizationTask is a task to rerun image characterization (determine the PSF model and measure aperture corrections) after initial characterization, calibration, and isolated star association. Currently, this allows PSF stars to be reserved consistently for all overlapping visits/detectors. In the future, this task will allow PSF and aperture correction modeling to take advantage of full visits (utilizing all the detectors) as well as the refined astrometric model.

Processing summary

FinalizeCharacterizationTask first reads the isolated source association table to get a consistent list of PSF modeling and reserve stars, and then runs PSF modeling and aperture correction modeling per detector. In the first stage, the task will:

  • Read in isolated_star_cat and isolated_star_sources for all tracts that overlap the given visit.

  • Select isolated sources that have been detected in the band of the visit.

  • Reserve a configurable fraction of these isolated sources using the task configured in config.reserve_selection.

In the second stage, the task will run per-detector:

  • Select sources (src) from the calibrated exposure (calexp) above a configurable signal-to-noise.

  • Match by source id to the isolated_star_sources and mark PSF candidate and reserve stars.

  • Make PSF candidates using the task configured in config.make_psf_candidates.

  • Determine the PSF using the configured PSF determination task configured in config.psf_determiner.

  • Run measurement on the PSF candidate, used, and reserved stars using the task configured in config.measurement.

  • Run the aperture correction measurement task configured in config.measure_ap_corr using the PSF stars.

  • Run the aperture correction application task configured in config.apply_ap_corr on the PSF stars.

An exposure catalog containing all the PSF models in the visit, another containing all the aperture correction maps in the visit, and a data frame with all the measurements and flags are returned for persistence.

Python API summary

from lsst.pipe.tasks.finalizeCharacterization import FinalizeCharacterizationTask
classFinalizeCharacterizationTask(initInputs=None, **kwargs)

Run final characterization on exposures...

attributeconfig

Access configuration fields and retargetable subtasks.

methodrun(visit, band, isolated_star_cat_dict, isolated_star_source_dict, src_dict, calexp_dict)

Run the FinalizeCharacterizationTask...

See also

See the FinalizeCharacterizationTask API reference for complete details.

Retargetable subtasks

apply_ap_corr

Default

lsst.meas.base.applyApCorr.ApplyApCorrTask

Field type

ConfigurableField

Subtask to apply aperture corrections

make_psf_candidates

Default

lsst.meas.algorithms.makePsfCandidates.MakePsfCandidatesTask

Field type

ConfigurableField

Task to make psf candidates from selected stars.

measure_ap_corr

Default

lsst.meas.algorithms.measureApCorr.MeasureApCorrTask

Field type

ConfigurableField

Subtask to measure aperture corrections

measurement

Default

lsst.meas.base.sfm.SingleFrameMeasurementTask

Field type

ConfigurableField

Measure sources for aperture corrections

psf_determiner

Default
'piff'
Field type

Single-selection RegistryField

Choices
'pca'

lsst.meas.algorithms.pcaPsfDeterminer.PcaPsfDeterminerTask

'piff'

lsst.meas.extensions.piff.piffPsfDeterminer.PiffPsfDeterminerTask

'psfex'

lsst.meas.extensions.psfex.psfexPsfDeterminer.PsfexPsfDeterminerTask

PSF Determination algorithm

reserve_selection

Default

lsst.pipe.tasks.reserveIsolatedStars.ReserveIsolatedStarsTask

Field type

ConfigurableField

Task to select reserved stars

source_selector

Default
'science'
Field type

Single-selection RegistryField

Choices
'science'

lsst.meas.algorithms.sourceSelector.ScienceSourceSelectorTask

'references'

lsst.meas.algorithms.sourceSelector.ReferenceSourceSelectorTask

'null'

lsst.meas.algorithms.sourceSelector.NullSourceSelectorTask

'objectSize'

lsst.meas.algorithms.objectSizeStarSelector.ObjectSizeStarSelectorTask

'flagged'

lsst.meas.algorithms.flaggedSourceSelector.FlaggedSourceSelectorTask

'astrometry'

lsst.meas.algorithms.astrometrySourceSelector.AstrometrySourceSelectorTask

'matcher'

lsst.meas.algorithms.matcherSourceSelector.MatcherSourceSelectorTask

'diaCatalog'

lsst.ip.diffim.diaCatalogSourceSelector.DiaCatalogSourceSelectorTask

How to select sources

Configuration fields

connections

Data type

lsst.pipe.base.config.FinalizeCharacterizationConfigConnections

Field type

ConfigField

Configurations describing the connections of the PipelineTask to datatypes

id_column

Default
'sourceId'
Field type

str Field

Name of column in isolated_star_sources with source id.

saveLogOutput

Default
True
Field type

bool Field

Flag to enable/disable saving of log output for a task, enabled by default.

saveMetadata

Default
True
Field type

bool Field

Flag to enable/disable metadata saving for a task, enabled by default. Deprecated: This field is deprecated and will be removed after v26.