ProcessCcdWithFakesTask

class lsst.pipe.tasks.processCcdWithFakes.ProcessCcdWithFakesTask(*args, **kwargs)

Bases: PipelineTask

Insert fake objects into calexps.

Add fake stars and galaxies to the given calexp, specified in the dataRef. Galaxy parameters are read in from the specified file and then modelled using galsim. Re-runs characterize image and calibrate image to give a new background estimation and measurement of the calexp.

ProcessFakeSourcesTask inherits six functions from insertFakesTask that make images of the fake sources and then add them to the calexp.

addPixCoords

Use the WCS information to add the pixel coordinates of each source Adds an x and y column to the catalog of fake sources.

trimFakeCat

Trim the fake cat to about the size of the input image.

mkFakeGalsimGalaxies

Use Galsim to make fake double sersic galaxies for each set of galaxy parameters in the input file.

mkFakeStars

Use the PSF information from the calexp to make a fake star using the magnitude information from the input file.

cleanCat

Remove rows of the input fake catalog which have half light radius, of either the bulge or the disk, that are 0.

addFakeSources

Add the fake sources to the calexp.

Notes

The calexp with fake souces added to it is written out as the datatype calexp_fakes.

Deprecated since version v28.0: This task will be removed in v28.0 as it is replaced by source_injection tasks.

Methods Summary

composeFakeCat(fakeCats, skyMap)	Concatenate the fakeCats from tracts that may cover the exposure.
copyCalibrationFields(calibCat, sourceCat, ...)	Match sources in calibCat and sourceCat and copy the specified fields
getVisitMatchedFakeCat(fakeCat, exposure)	Trim the fakeCat to select particular visit
run(fakeCats, exposure, skyMap[, wcs, ...])	Add fake sources to a calexp and then run detection, deblending and measurement.
runQuantum(butlerQC, inputRefs, outputRefs)	Do butler IO and transform to provide in memory objects for tasks run method.

Methods Documentation

composeFakeCat(fakeCats, skyMap)

Concatenate the fakeCats from tracts that may cover the exposure.

Parameters

fakeCatslist of lsst.daf.butler.DeferredDatasetHandle

Set of fake cats to concatenate.

skyMaplsst.skymap.SkyMap

SkyMap defining the geometry of the tracts and patches.

Returns

combinedFakeCatpandas.DataFrame

All fakes that cover the inner polygon of the tracts in this quantum.

copyCalibrationFields(calibCat, sourceCat, fieldsToCopy)

Match sources in calibCat and sourceCat and copy the specified fields

Parameters

calibCatlsst.afw.table.SourceCatalog

Catalog from which to copy fields.

sourceCatlsst.afw.table.SourceCatalog

Catalog to which to copy fields.

fieldsToCopylsst.pex.config.listField.List

Fields to copy from calibCat to SoourceCat.

Returns

newCatlsst.afw.table.SourceCatalog

Catalog which includes the copied fields.

The fields copied are those specified by fieldsToCopy that actually exist in the schema of calibCat.

This version was based on and adapted from the one in calibrateTask.

getVisitMatchedFakeCat(fakeCat, exposure)

Trim the fakeCat to select particular visit

Parameters

fakeCatpandas.core.frame.DataFrame

The catalog of fake sources to add to the exposure

exposurelsst.afw.image.exposure.exposure.ExposureF

The exposure to add the fake sources to

Returns

movingFakeCatpandas.DataFrame

All fakes that belong to the visit

run(fakeCats, exposure, skyMap, wcs=None, photoCalib=None, icSourceCat=None, sfdSourceCat=None, externalSkyWcsGlobalCatalog=None, externalSkyWcsTractCatalog=None, externalPhotoCalibGlobalCatalog=None, externalPhotoCalibTractCatalog=None, idGenerator=None)

Add fake sources to a calexp and then run detection, deblending and measurement.

Parameters

fakeCatslist of lsst.daf.butler.DeferredDatasetHandle

Set of tract level fake catalogs that potentially cover this detectorVisit.

exposurelsst.afw.image.exposure.exposure.ExposureF

The exposure to add the fake sources to.

skyMaplsst.skymap.SkyMap

SkyMap defining the tracts and patches the fakes are stored over.

wcslsst.afw.geom.SkyWcs, optional

WCS to use to add fake sources.

photoCaliblsst.afw.image.photoCalib.PhotoCalib, optional

Photometric calibration to be used to calibrate the fake sources.

icSourceCatlsst.afw.table.SourceCatalog, optional

Catalog to take the information about which sources were used for calibration from.

sfdSourceCatlsst.afw.table.SourceCatalog, optional

Catalog produced by singleFrameDriver, needed to copy some calibration flags from.

externalSkyWcsGlobalCataloglsst.afw.table.ExposureCatalog, optional

Exposure catalog with external skyWcs to be applied per config.

externalSkyWcsTractCataloglsst.afw.table.ExposureCatalog, optional

Exposure catalog with external skyWcs to be applied per config.

externalPhotoCalibGlobalCataloglsst.afw.table.ExposureCatalog, optional

Exposure catalog with external photoCalib to be applied per config

externalPhotoCalibTractCataloglsst.afw.table.ExposureCatalog, optional

Exposure catalog with external photoCalib to be applied per config.

idGeneratorlsst.meas.base.IdGenerator, optional

Object that generates Source IDs and random seeds.

Returns

resultStructlsst.pipe.base.struct.Struct

Result struct containing:

• outputExposure: lsst.afw.image.exposure.exposure.ExposureF

• outputCat: lsst.afw.table.source.source.SourceCatalog

Notes

Adds pixel coordinates for each source to the fakeCat and removes objects with bulge or disk half light radius = 0 (if config.cleanCat = True). These columns are called x and y and are in pixels.

Adds the Fake mask plane to the exposure which is then set by addFakeSources to mark where fake sources have been added. Uses the information in the fakeCat to make fake galaxies (using galsim) and fake stars, using the PSF models from the PSF information for the calexp. These are then added to the calexp and the calexp with fakes included returned.

The galsim galaxies are made using a double sersic profile, one for the bulge and one for the disk, this is then convolved with the PSF at that point.

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.