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...

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
'psfex': lsst.meas.extensions.psfex.psfexPsfDeterminer.PsfexPsfDeterminerTask
'piff': lsst.meas.extensions.piff.piffPsfDeterminer.PiffPsfDeterminerTask

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

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.

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