ProcessCcdWithFakesTask¶

class lsst.pipe.tasks.processCcdWithFakes.ProcessCcdWithFakesTask(schema=None, butler=None, **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.

Attributes Summary

canMultiprocess

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
`emptyMetadata`()	Empty (clear) the metadata for this Task and all sub-Tasks.
`getFullMetadata`()	Get metadata for all tasks.
`getFullName`()	Get the task name as a hierarchical name including parent task names.
`getName`()	Get the name of the task.
`getResourceConfig`()	Return resource configuration for this task.
`getTaskDict`()	Get a dictionary of all tasks as a shallow copy.
`getVisitMatchedFakeCat`(fakeCat, exposure)	Trim the fakeCat to select particular visit
`makeField`(doc)	Make a `lsst.pex.config.ConfigurableField` for this task.
`makeSubtask`(name, **keyArgs)	Create a subtask as a new instance as the `name` attribute of this task.
`run`(fakeCats, exposure, skyMap[, wcs, ...])	Add fake sources to a calexp and then run detection, deblending and measurement.
`runQuantum`(butlerQC, inputRefs, outputRefs)	Method to do butler IO and or transforms to provide in memory objects for tasks run method
`timer`(name[, logLevel])	Context manager to log performance data for an arbitrary block of code.

Attributes Documentation

canMultiprocess: ClassVar[bool] = True¶

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.

emptyMetadata() → None¶: Empty (clear) the metadata for this Task and all sub-Tasks.

getFullMetadata() → TaskMetadata¶

Get metadata for all tasks.

Returns:

metadataTaskMetadata: The keys are the full task name. Values are metadata for the top-level task and all subtasks, sub-subtasks, etc.

Notes

The returned metadata includes timing information (if @timer.timeMethod is used) and any metadata set by the task. The name of each item consists of the full task name with . replaced by :, followed by . and the name of the item, e.g.:

topLevelTaskName:subtaskName:subsubtaskName.itemName

using : in the full task name disambiguates the rare situation that a task has a subtask and a metadata item with the same name.

getFullName() → str¶

Get the task name as a hierarchical name including parent task names.

Returns:

fullNamestr

The full name consists of the name of the parent task and each subtask separated by periods. For example:

The full name of top-level task “top” is simply “top”.
The full name of subtask “sub” of top-level task “top” is “top.sub”.
The full name of subtask “sub2” of subtask “sub” of top-level task “top” is “top.sub.sub2”.

getName() → str¶

Get the name of the task.

Returns:

taskNamestr: Name of the task.

See also

getFullName

getResourceConfig() → ResourceConfig | None¶

Return resource configuration for this task.

Returns:

Object of type ResourceConfig or None if resource
configuration is not defined for this task.

getTaskDict() → Dict[str, ReferenceType[Task]]¶

Get a dictionary of all tasks as a shallow copy.

Returns:

taskDictdict: Dictionary containing full task name: task object for the top-level task and all subtasks, sub-subtasks, etc.

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

classmethod makeField(doc: str) → ConfigurableField¶

Make a lsst.pex.config.ConfigurableField for this task.

Parameters:

docstr: Help text for the field.

Returns:

configurableFieldlsst.pex.config.ConfigurableField: A ConfigurableField for this task.

Examples

Provides a convenient way to specify this task is a subtask of another task.

Here is an example of use:

class OtherTaskConfig(lsst.pex.config.Config):
    aSubtask = ATaskClass.makeField("brief description of task")

makeSubtask(name: str, **keyArgs: Any) → None¶

Create a subtask as a new instance as the name attribute of this task.

Parameters:

namestr

Brief name of the subtask.

keyArgs

Extra keyword arguments used to construct the task. The following arguments are automatically provided and cannot be overridden:

“config”.
“parentTask”.

Notes

The subtask must be defined by Task.config.name, an instance of ConfigurableField or RegistryField.

run(fakeCats, exposure, skyMap, wcs=None, photoCalib=None, exposureIdInfo=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.
exposureIdInfolsst.obs.base.ExposureIdInfo, optional: Object that carries ID information for this image/catalog. Deprecated in favor of idGenerator.
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)¶

Method to do butler IO and or transforms to provide in memory objects for tasks run method

Parameters:

butlerQCButlerQuantumContext: 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.

timer(name: str, logLevel: int = 10) → Iterator[None]¶

Context manager to log performance data for an arbitrary block of code.

Parameters:

namestr: Name of code being timed; data will be logged using item name: Start and End.
logLevel: A logging level constant.

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ProcessCcdWithFakesTask¶