finalizeCharacterization.py

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#
# LSST Data Management System
# Copyright 2008-2022 AURA/LSST.
#
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# LSST Project (http://www.lsst.org/).
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"""Task to run a finalized image characterization, using additional data.
"""
import numpy as np
import esutil
import pandas as pd
 
import lsst.pex.config as pexConfig
import lsst.pipe.base as pipeBase
import lsst.daf.base as dafBase
import lsst.afw.table as afwTable
import lsst.meas.algorithms as measAlg
import lsst.meas.extensions.piff.piffPsfDeterminer  # noqa: F401
from lsst.meas.algorithms import MeasureApCorrTask
from lsst.meas.base import SingleFrameMeasurementTask, ApplyApCorrTask
from lsst.meas.algorithms.sourceSelector import sourceSelectorRegistry
 
from .reserveIsolatedStars import ReserveIsolatedStarsTask
 
__all__ = ['FinalizeCharacterizationConnections',
           'FinalizeCharacterizationConfig',
           'FinalizeCharacterizationTask']
 
 
class FinalizeCharacterizationConnections(pipeBase.PipelineTaskConnections,
                                          dimensions=('instrument', 'visit',),
                                          defaultTemplates={}):
    src_schema = pipeBase.connectionTypes.InitInput(
        doc='Input schema used for src catalogs.',
        name='src_schema',
        storageClass='SourceCatalog',
    )
    srcs = pipeBase.connectionTypes.Input(
        doc='Source catalogs for the visit',
        name='src',
        storageClass='SourceCatalog',
        dimensions=('instrument', 'visit', 'detector'),
        deferLoad=True,
        multiple=True,
    )
    calexps = pipeBase.connectionTypes.Input(
        doc='Calexps for the visit',
        name='calexp',
        storageClass='ExposureF',
        dimensions=('instrument', 'visit', 'detector'),
        deferLoad=True,
        multiple=True,
    )
    isolated_star_cats = pipeBase.connectionTypes.Input(
        doc=('Catalog of isolated stars with average positions, number of associated '
             'sources, and indexes to the isolated_star_sources catalogs.'),
        name='isolated_star_cat',
        storageClass='DataFrame',
        dimensions=('instrument', 'tract', 'skymap'),
        deferLoad=True,
        multiple=True,
    )
    isolated_star_sources = pipeBase.connectionTypes.Input(
        doc=('Catalog of isolated star sources with sourceIds, and indexes to the '
             'isolated_star_cats catalogs.'),
        name='isolated_star_sources',
        storageClass='DataFrame',
        dimensions=('instrument', 'tract', 'skymap'),
        deferLoad=True,
        multiple=True,
    )
    finalized_psf_ap_corr_cat = pipeBase.connectionTypes.Output(
        doc=('Per-visit finalized psf models and aperture corrections.  This '
             'catalog uses detector id for the id and are sorted for fast '
             'lookups of a detector.'),
        name='finalized_psf_ap_corr_catalog',
        storageClass='ExposureCatalog',
        dimensions=('instrument', 'visit'),
    )
    finalized_src_table = pipeBase.connectionTypes.Output(
        doc=('Per-visit catalog of measurements for psf/flag/etc.'),
        name='finalized_src_table',
        storageClass='DataFrame',
        dimensions=('instrument', 'visit'),
    )
 
 
class FinalizeCharacterizationConfig(pipeBase.PipelineTaskConfig,
                                     pipelineConnections=FinalizeCharacterizationConnections):
    """Configuration for FinalizeCharacterizationTask."""
    source_selector = sourceSelectorRegistry.makeField(
        doc="How to select sources",
        default="science"
    )
    id_column = pexConfig.Field(
        doc='Name of column in isolated_star_sources with source id.',
        dtype=str,
        default='sourceId',
    )
    reserve_selection = pexConfig.ConfigurableField(
        target=ReserveIsolatedStarsTask,
        doc='Task to select reserved stars',
    )
    make_psf_candidates = pexConfig.ConfigurableField(
        target=measAlg.MakePsfCandidatesTask,
        doc='Task to make psf candidates from selected stars.',
    )
    psf_determiner = measAlg.psfDeterminerRegistry.makeField(
        'PSF Determination algorithm',
        default='piff'
    )
    measurement = pexConfig.ConfigurableField(
        target=SingleFrameMeasurementTask,
        doc='Measure sources for aperture corrections'
    )
    measure_ap_corr = pexConfig.ConfigurableField(
        target=MeasureApCorrTask,
        doc="Subtask to measure aperture corrections"
    )
    apply_ap_corr = pexConfig.ConfigurableField(
        target=ApplyApCorrTask,
        doc="Subtask to apply aperture corrections"
    )
 
    def setDefaults(self):
        super().setDefaults()
 
        source_selector = self.source_selectorsource_selector['science']
        source_selector.setDefaults()
 
        # We use the source selector only to select out flagged objects
        # and signal-to-noise.  Isolated, unresolved sources are handled
        # by the isolated star catalog.
 
        source_selector.doFlags = True
        source_selector.doSignalToNoise = True
        source_selector.doFluxLimit = False
        source_selector.doUnresolved = False
        source_selector.doIsolated = False
 
        source_selector.signalToNoise.minimum = 20.0
        source_selector.signalToNoise.maximum = 1000.0
 
        source_selector.signalToNoise.fluxField = 'base_GaussianFlux_instFlux'
        source_selector.signalToNoise.errField = 'base_GaussianFlux_instFluxErr'
 
        source_selector.flags.bad = ['base_PixelFlags_flag_edge',
                                     'base_PixelFlags_flag_interpolatedCenter',
                                     'base_PixelFlags_flag_saturatedCenter',
                                     'base_PixelFlags_flag_crCenter',
                                     'base_PixelFlags_flag_bad',
                                     'base_PixelFlags_flag_interpolated',
                                     'base_PixelFlags_flag_saturated',
                                     'slot_Centroid_flag',
                                     'base_GaussianFlux_flag']
 
        # Configure aperture correction to select only high s/n sources (that
        # were used in the psf modeling) to avoid background problems when
        # computing the aperture correction map.
        self.measure_ap_corrmeasure_ap_corr.sourceSelector = 'science'
 
        ap_selector = self.measure_ap_corrmeasure_ap_corr.sourceSelector['science']
        ap_selector.doFluxLimit = False
        ap_selector.doFlags = True
        ap_selector.doUnresolved = False
        ap_selector.doSignalToNoise = True
        ap_selector.doIsolated = False
        ap_selector.flags.good = ['calib_psf_used']
        ap_selector.flags.bad = []
        ap_selector.signalToNoise.minimum = 200.0
        ap_selector.signalToNoise.maximum = None
        ap_selector.signalToNoise.fluxField = 'base_PsfFlux_instFlux'
        ap_selector.signalToNoise.errField = 'base_PsfFlux_instFluxErr'
 
        import lsst.meas.modelfit  # noqa: F401
        import lsst.meas.extensions.photometryKron  # noqa: F401
        import lsst.meas.extensions.convolved  # noqa: F401
        import lsst.meas.extensions.gaap  # noqa: F401
        import lsst.meas.extensions.shapeHSM  # noqa: F401
 
        # Set up measurement defaults
        self.measurementmeasurement.plugins.names = [
            'base_PsfFlux',
            'base_GaussianFlux',
            'modelfit_DoubleShapeletPsfApprox',
            'modelfit_CModel',
            'ext_photometryKron_KronFlux',
            'ext_convolved_ConvolvedFlux',
            'ext_gaap_GaapFlux',
            'ext_shapeHSM_HsmShapeRegauss',
            'ext_shapeHSM_HsmSourceMoments',
            'ext_shapeHSM_HsmPsfMoments',
            'ext_shapeHSM_HsmSourceMomentsRound',
        ]
        self.measurementmeasurement.slots.modelFlux = 'modelfit_CModel'
        self.measurementmeasurement.plugins['ext_convolved_ConvolvedFlux'].seeing.append(8.0)
        self.measurementmeasurement.plugins['ext_gaap_GaapFlux'].sigmas = [
            0.5,
            0.7,
            1.0,
            1.5,
            2.5,
            3.0
        ]
        self.measurementmeasurement.plugins['ext_gaap_GaapFlux'].doPsfPhotometry = True
        self.measurementmeasurement.slots.shape = 'ext_shapeHSM_HsmSourceMoments'
        self.measurementmeasurement.slots.psfShape = 'ext_shapeHSM_HsmPsfMoments'
        self.measurementmeasurement.plugins['ext_shapeHSM_HsmShapeRegauss'].deblendNChild = ""
        # Turn off slot setting for measurement for centroid and shape
        # (for which we use the input src catalog measurements)
        self.measurementmeasurement.slots.centroid = None
        self.measurementmeasurement.slots.apFlux = None
        self.measurementmeasurement.slots.calibFlux = None
 
        names = self.measurementmeasurement.plugins['ext_convolved_ConvolvedFlux'].getAllResultNames()
        self.measure_ap_corrmeasure_ap_corr.allowFailure += names
        names = self.measurementmeasurement.plugins["ext_gaap_GaapFlux"].getAllGaapResultNames()
        self.measure_ap_corrmeasure_ap_corr.allowFailure += names
 
 
class FinalizeCharacterizationTask(pipeBase.PipelineTask):
    """Run final characterization on exposures."""
    ConfigClass = FinalizeCharacterizationConfig
    _DefaultName = 'finalize_characterization'
 
    def __init__(self, initInputs=None, **kwargs):
        super().__init__(initInputs=initInputs, **kwargs)
 
        self.schema_mapper, self.schemaschema = self._make_output_schema_mapper_make_output_schema_mapper(
            initInputs['src_schema'].schema
        )
 
        self.makeSubtask('reserve_selection')
        self.makeSubtask('source_selector')
        self.makeSubtask('make_psf_candidates')
        self.makeSubtask('psf_determiner')
        self.makeSubtask('measurement', schema=self.schemaschema)
        self.makeSubtask('measure_ap_corr', schema=self.schemaschema)
        self.makeSubtask('apply_ap_corr', schema=self.schemaschema)
 
        # Only log warning and fatal errors from the source_selector
        self.source_selector.log.setLevel(self.source_selector.log.WARN)
 
    def runQuantum(self, butlerQC, inputRefs, outputRefs):
        input_handle_dict = butlerQC.get(inputRefs)
 
        band = butlerQC.quantum.dataId['band']
        visit = butlerQC.quantum.dataId['visit']
 
        src_dict_temp = {handle.dataId['detector']: handle
                         for handle in input_handle_dict['srcs']}
        calexp_dict_temp = {handle.dataId['detector']: handle
                            for handle in input_handle_dict['calexps']}
        isolated_star_cat_dict_temp = {handle.dataId['tract']: handle
                                       for handle in input_handle_dict['isolated_star_cats']}
        isolated_star_source_dict_temp = {handle.dataId['tract']: handle
                                          for handle in input_handle_dict['isolated_star_sources']}
        # TODO: Sort until DM-31701 is done and we have deterministic
        # dataset ordering.
        src_dict = {detector: src_dict_temp[detector] for
                    detector in sorted(src_dict_temp.keys())}
        calexp_dict = {detector: calexp_dict_temp[detector] for
                       detector in sorted(calexp_dict_temp.keys())}
        isolated_star_cat_dict = {tract: isolated_star_cat_dict_temp[tract] for
                                  tract in sorted(isolated_star_cat_dict_temp.keys())}
        isolated_star_source_dict = {tract: isolated_star_source_dict_temp[tract] for
                                     tract in sorted(isolated_star_source_dict_temp.keys())}
 
        struct = self.runrun(visit,
                          band,
                          isolated_star_cat_dict,
                          isolated_star_source_dict,
                          src_dict,
                          calexp_dict)
 
        butlerQC.put(struct.psf_ap_corr_cat,
                     outputRefs.finalized_psf_ap_corr_cat)
        butlerQC.put(pd.DataFrame(struct.output_table),
                     outputRefs.finalized_src_table)
 
    def run(self, visit, band, isolated_star_cat_dict, isolated_star_source_dict, src_dict, calexp_dict):
        """
        Run the FinalizeCharacterizationTask.
 
        Parameters
        ----------
        visit : `int`
            Visit number.  Used in the output catalogs.
        band : `str`
            Band name.  Used to select reserved stars.
        isolated_star_cat_dict : `dict`
            Per-tract dict of isolated star catalog handles.
        isolated_star_source_dict : `dict`
            Per-tract dict of isolated star source catalog handles.
        src_dict : `dict`
            Per-detector dict of src catalog handles.
        calexp_dict : `dict`
            Per-detector dict of calibrated exposure handles.
 
        Returns
        -------
        struct : `lsst.pipe.base.struct`
            Struct with outputs for persistence.
        """
        # We do not need the isolated star table in this task.
        # However, it is used in tests to confirm consistency of indexes.
        _, isolated_source_table = self.concat_isolated_star_catsconcat_isolated_star_cats(
            band,
            isolated_star_cat_dict,
            isolated_star_source_dict
        )
 
        exposure_cat_schema = afwTable.ExposureTable.makeMinimalSchema()
        exposure_cat_schema.addField('visit', type='L', doc='Visit number')
 
        metadata = dafBase.PropertyList()
        metadata.add("COMMENT", "Catalog id is detector id, sorted.")
        metadata.add("COMMENT", "Only detectors with data have entries.")
 
        psf_ap_corr_cat = afwTable.ExposureCatalog(exposure_cat_schema)
        psf_ap_corr_cat.setMetadata(metadata)
 
        measured_src_tables = []
 
        for detector in src_dict:
            src = src_dict[detector].get()
            exposure = calexp_dict[detector].get()
 
            psf, ap_corr_map, measured_src = self.compute_psf_and_ap_corr_mapcompute_psf_and_ap_corr_map(
                visit,
                detector,
                exposure,
                src,
                isolated_source_table
            )
 
            # And now we package it together...
            record = psf_ap_corr_cat.addNew()
            record['id'] = int(detector)
            record['visit'] = visit
            if psf is not None:
                record.setPsf(psf)
            if ap_corr_map is not None:
                record.setApCorrMap(ap_corr_map)
 
            measured_src['visit'][:] = visit
            measured_src['detector'][:] = detector
 
            measured_src_tables.append(measured_src.asAstropy().as_array())
 
        measured_src_table = np.concatenate(measured_src_tables)
 
        return pipeBase.Struct(psf_ap_corr_cat=psf_ap_corr_cat,
                               output_table=measured_src_table)
 
    def _make_output_schema_mapper(self, input_schema):
        """Make the schema mapper from the input schema to the output schema.
 
        Parameters
        ----------
        input_schema : `lsst.afw.table.Schema`
            Input schema.
 
        Returns
        -------
        mapper : `lsst.afw.table.SchemaMapper`
            Schema mapper
        output_schema : `lsst.afw.table.Schema`
            Output schema (with alias map)
        """
        mapper = afwTable.SchemaMapper(input_schema)
        mapper.addMinimalSchema(afwTable.SourceTable.makeMinimalSchema())
        mapper.addMapping(input_schema['slot_Centroid_x'].asKey())
        mapper.addMapping(input_schema['slot_Centroid_y'].asKey())
 
        # The aperture fields may be used by the psf determiner.
        aper_fields = input_schema.extract('base_CircularApertureFlux_*')
        for field, item in aper_fields.items():
            mapper.addMapping(item.key)
 
        # The following two may be redundant, but then the mapping is a no-op.
        apflux_fields = input_schema.extract('slot_ApFlux_*')
        for field, item in apflux_fields.items():
            mapper.addMapping(item.key)
 
        calibflux_fields = input_schema.extract('slot_CalibFlux_*')
        for field, item in calibflux_fields.items():
            mapper.addMapping(item.key)
 
        mapper.addMapping(
            input_schema[self.config.source_selector.active.signalToNoise.fluxField].asKey(),
            'calib_psf_selection_flux')
        mapper.addMapping(
            input_schema[self.config.source_selector.active.signalToNoise.errField].asKey(),
            'calib_psf_selection_flux_err')
 
        output_schema = mapper.getOutputSchema()
 
        output_schema.addField(
            'calib_psf_candidate',
            type='Flag',
            doc=('set if the source was a candidate for PSF determination, '
                 'as determined from FinalizeCharacterizationTask.'),
        )
        output_schema.addField(
            'calib_psf_reserved',
            type='Flag',
            doc=('set if source was reserved from PSF determination by '
                 'FinalizeCharacterizationTask.'),
        )
        output_schema.addField(
            'calib_psf_used',
            type='Flag',
            doc=('set if source was used in the PSF determination by '
                 'FinalizeCharacterizationTask.'),
        )
        output_schema.addField(
            'visit',
            type=np.int64,
            doc='Visit number for the sources.',
        )
        output_schema.addField(
            'detector',
            type=np.int32,
            doc='Detector number for the sources.',
        )
 
        alias_map = input_schema.getAliasMap()
        alias_map_output = afwTable.AliasMap()
        alias_map_output.set('slot_Centroid', alias_map.get('slot_Centroid'))
        alias_map_output.set('slot_ApFlux', alias_map.get('slot_ApFlux'))
        alias_map_output.set('slot_CalibFlux', alias_map.get('slot_CalibFlux'))
 
        output_schema.setAliasMap(alias_map_output)
 
        return mapper, output_schema
 
    def _make_selection_schema_mapper(self, input_schema):
        """Make the schema mapper from the input schema to the selection schema.
 
        Parameters
        ----------
        input_schema : `lsst.afw.table.Schema`
            Input schema.
 
        Returns
        -------
        mapper : `lsst.afw.table.SchemaMapper`
            Schema mapper
        selection_schema : `lsst.afw.table.Schema`
            Selection schema (with alias map)
        """
        mapper = afwTable.SchemaMapper(input_schema)
        mapper.addMinimalSchema(input_schema)
 
        selection_schema = mapper.getOutputSchema()
 
        selection_schema.setAliasMap(input_schema.getAliasMap())
 
        return mapper, selection_schema
 
    def concat_isolated_star_cats(self, band, isolated_star_cat_dict, isolated_star_source_dict):
        """
        Concatenate isolated star catalogs and make reserve selection.
 
        Parameters
        ----------
        band : `str`
            Band name.  Used to select reserved stars.
        isolated_star_cat_dict : `dict`
            Per-tract dict of isolated star catalog handles.
        isolated_star_source_dict : `dict`
            Per-tract dict of isolated star source catalog handles.
 
        Returns
        -------
        isolated_table : `np.ndarray` (N,)
            Table of isolated stars, with indexes to isolated sources.
        isolated_source_table : `np.ndarray` (M,)
            Table of isolated sources, with indexes to isolated stars.
        """
        isolated_tables = []
        isolated_sources = []
        merge_cat_counter = 0
        merge_source_counter = 0
 
        for tract in isolated_star_cat_dict:
            df_cat = isolated_star_cat_dict[tract].get()
            table_cat = df_cat.to_records()
 
            df_source = isolated_star_source_dict[tract].get(
                parameters={'columns': [self.config.id_column,
                                        'obj_index']}
            )
            table_source = df_source.to_records()
 
            # Cut isolated star table to those observed in this band, and adjust indexes
            (use_band,) = (table_cat[f'nsource_{band}'] > 0).nonzero()
 
            if len(use_band) == 0:
                # There are no sources in this band in this tract.
                self.log.info("No sources found in %s band in tract %d.", band, tract)
                continue
 
            # With the following matching:
            #   table_source[b] <-> table_cat[use_band[a]]
            obj_index = table_source['obj_index'][:]
            a, b = esutil.numpy_util.match(use_band, obj_index)
 
            # Update indexes and cut to band-selected stars/sources
            table_source['obj_index'][b] = a
            _, index_new = np.unique(a, return_index=True)
            table_cat[f'source_cat_index_{band}'][use_band] = index_new
 
            # After the following cuts, the catalogs have the following properties:
            # - table_cat only contains isolated stars that have at least one source
            #   in ``band``.
            # - table_source only contains ``band`` sources.
            # - The slice table_cat["source_cat_index_{band}"]: table_cat["source_cat_index_{band}"]
            #                                                   + table_cat["nsource_{band}]
            #   applied to table_source will give all the sources associated with the star.
            # - For each source, table_source["obj_index"] points to the index of the associated
            #   isolated star.
            table_source = table_source[b]
            table_cat = table_cat[use_band]
 
            # Add reserved flag column to tables
            table_cat = np.lib.recfunctions.append_fields(
                table_cat,
                'reserved',
                np.zeros(table_cat.size, dtype=bool),
                usemask=False
            )
            table_source = np.lib.recfunctions.append_fields(
                table_source,
                'reserved',
                np.zeros(table_source.size, dtype=bool),
                usemask=False
            )
 
            # Get reserve star flags
            table_cat['reserved'][:] = self.reserve_selection.run(
                len(table_cat),
                extra=f'{band}_{tract}',
            )
            table_source['reserved'][:] = table_cat['reserved'][table_source['obj_index']]
 
            # Offset indexes to account for tract merging
            table_cat[f'source_cat_index_{band}'] += merge_source_counter
            table_source['obj_index'] += merge_cat_counter
 
            isolated_tables.append(table_cat)
            isolated_sources.append(table_source)
 
            merge_cat_counter += len(table_cat)
            merge_source_counter += len(table_source)
 
        isolated_table = np.concatenate(isolated_tables)
        isolated_source_table = np.concatenate(isolated_sources)
 
        return isolated_table, isolated_source_table
 
    def compute_psf_and_ap_corr_map(self, visit, detector, exposure, src, isolated_source_table):
        """Compute psf model and aperture correction map for a single exposure.
 
        Parameters
        ----------
        visit : `int`
            Visit number (for logging).
        detector : `int`
            Detector number (for logging).
        exposure : `lsst.afw.image.ExposureF`
        src : `lsst.afw.table.SourceCatalog`
        isolated_source_table : `np.ndarray`
 
        Returns
        -------
        psf : `lsst.meas.algorithms.ImagePsf`
            PSF Model
        ap_corr_map : `lsst.afw.image.ApCorrMap`
            Aperture correction map.
        measured_src : `lsst.afw.table.SourceCatalog`
            Updated source catalog with measurements, flags and aperture corrections.
        """
        # Apply source selector (s/n, flags, etc.)
        good_src = self.source_selector.selectSources(src)
 
        # Cut down input src to the selected sources
        # We use a separate schema/mapper here than for the output/measurement catalog because of
        # clashes between fields that were previously run and those that need to be rerun with
        # the new psf model.  This may be slightly inefficient but keeps input
        # and output values cleanly separated.
        selection_mapper, selection_schema = self._make_selection_schema_mapper_make_selection_schema_mapper(src.schema)
 
        selected_src = afwTable.SourceCatalog(selection_schema)
        selected_src.reserve(good_src.selected.sum())
        selected_src.extend(src[good_src.selected], mapper=selection_mapper)
 
        # The calib flags have been copied from the input table,
        # and we reset them here just to ensure they aren't propagated.
        selected_src['calib_psf_candidate'] = np.zeros(len(selected_src), dtype=bool)
        selected_src['calib_psf_used'] = np.zeros(len(selected_src), dtype=bool)
        selected_src['calib_psf_reserved'] = np.zeros(len(selected_src), dtype=bool)
 
        # Find the isolated sources and set flags
        matched_src, matched_iso = esutil.numpy_util.match(
            selected_src['id'],
            isolated_source_table[self.config.id_column]
        )
 
        matched_arr = np.zeros(len(selected_src), dtype=bool)
        matched_arr[matched_src] = True
        selected_src['calib_psf_candidate'] = matched_arr
 
        reserved_arr = np.zeros(len(selected_src), dtype=bool)
        reserved_arr[matched_src] = isolated_source_table['reserved'][matched_iso]
        selected_src['calib_psf_reserved'] = reserved_arr
 
        selected_src = selected_src[selected_src['calib_psf_candidate']].copy(deep=True)
 
        # Make the measured source catalog as well, based on the selected catalog.
        measured_src = afwTable.SourceCatalog(self.schemaschema)
        measured_src.reserve(len(selected_src))
        measured_src.extend(selected_src, mapper=self.schema_mapper)
 
        # We need to copy over the calib_psf flags because they were not in the mapper
        measured_src['calib_psf_candidate'] = selected_src['calib_psf_candidate']
        measured_src['calib_psf_reserved'] = selected_src['calib_psf_reserved']
 
        # Select the psf candidates from the selection catalog
        try:
            psf_selection_result = self.make_psf_candidates.run(selected_src, exposure=exposure)
        except Exception as e:
            self.log.warning('Failed to make psf candidates for visit %d, detector %d: %s',
                             visit, detector, e)
            return None, None, measured_src
 
        psf_cand_cat = psf_selection_result.goodStarCat
 
        # Make list of psf candidates to send to the determiner
        # (omitting those marked as reserved)
        psf_determiner_list = [cand for cand, use
                               in zip(psf_selection_result.psfCandidates,
                                      ~psf_cand_cat['calib_psf_reserved']) if use]
        flag_key = psf_cand_cat.schema['calib_psf_used'].asKey()
        try:
            psf, cell_set = self.psf_determiner.determinePsf(exposure,
                                                             psf_determiner_list,
                                                             self.metadata,
                                                             flagKey=flag_key)
        except Exception as e:
            self.log.warning('Failed to determine psf for visit %d, detector %d: %s',
                             visit, detector, e)
            return None, None, measured_src
 
        # Set the psf in the exposure for measurement/aperture corrections.
        exposure.setPsf(psf)
 
        # At this point, we need to transfer the psf used flag from the selection
        # catalog to the measurement catalog.
        matched_selected, matched_measured = esutil.numpy_util.match(
            selected_src['id'],
            measured_src['id']
        )
        measured_used = np.zeros(len(measured_src), dtype=bool)
        measured_used[matched_measured] = selected_src['calib_psf_used'][matched_selected]
        measured_src['calib_psf_used'] = measured_used
 
        # Next, we do the measurement on all the psf candidate, used, and reserved stars.
        try:
            self.measurement.run(measCat=measured_src, exposure=exposure)
        except Exception as e:
            self.log.warning('Failed to make measurements for visit %d, detector %d: %s',
                             visit, detector, e)
            return psf, None, measured_src
 
        # And finally the ap corr map.
        try:
            ap_corr_map = self.measure_ap_corr.run(exposure=exposure,
                                                   catalog=measured_src).apCorrMap
        except Exception as e:
            self.log.warning('Failed to compute aperture corrections for visit %d, detector %d: %s',
                             visit, detector, e)
            return psf, None, measured_src
 
        self.apply_ap_corr.run(catalog=measured_src, apCorrMap=ap_corr_map)
 
        return psf, ap_corr_map, measured_src