CalibrateTask¶

class lsst.pipe.tasks.calibrate.CalibrateTask(astromRefObjLoader=None, photoRefObjLoader=None, icSourceSchema=None, initInputs=None, **kwargs)¶

Bases: PipelineTask

Calibrate an exposure: measure sources and perform astrometric and photometric calibration.

Given an exposure with a good PSF model and aperture correction map(e.g. as provided by CharacterizeImageTask), perform the following operations: - Run detection and measurement - Run astrometry subtask to fit an improved WCS - Run photoCal subtask to fit the exposure’s photometric zero-point

Parameters:

butlerNone: Compatibility parameter. Should always be None.
astromRefObjLoaderlsst.meas.algorithms.ReferenceObjectLoader, optional: Unused in gen3: must be None.
photoRefObjLoaderlsst.meas.algorithms.ReferenceObjectLoader, optional: Unused in gen3: must be None.
icSourceSchemalsst.afw.table.Schema, optional: Schema for the icSource catalog.
initInputsdict, optional: Dictionary that can contain a key icSourceSchema containing the input schema. If present will override the value of icSourceSchema.

Raises:

RuntimeError: Raised if any of the following occur: - isSourceCat is missing fields specified in icSourceFieldsToCopy. - PipelineTask form of this task is initialized with reference object

loaders.

Notes

Quantities set in exposure Metadata:

MAGZERO_RMS: MAGZERO’s RMS == sigma reported by photoCal task
MAGZERO_NOBJ: Number of stars used == ngood reported by photoCal task
COLORTERM1: ?? (always 0.0)
COLORTERM2: ?? (always 0.0)
COLORTERM3: ?? (always 0.0)

Debugging: CalibrateTask has a debug dictionary containing one key:

calibrate: frame (an int; <= 0 to not display) in which to display the exposure, sources and matches. See @ref lsst.meas.astrom.displayAstrometry for the meaning of the various symbols.

Attributes Summary

canMultiprocess

Whether this task can be run by an executor that uses subprocesses for parallelism.

Methods Summary

`copyCalibSourceFields`(calibType, ...)	Match sources in a calibrationCat and a sourceCat and copy 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.
`getTaskDict`()	Get a dictionary of all tasks as a shallow copy.
`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.
`recordMaskedPixelFractions`(exposure)	Record the fraction of all the pixels in an exposure that are masked with a given flag.
`run`(exposure[, background, icSourceCat, ...])	Calibrate an exposure.
`runQuantum`(butlerQC, inputRefs, outputRefs)	Do butler IO and transform to provide in memory objects for tasks `run` method.
`setMetadata`(exposure[, photoRes])	Set task and exposure metadata.
`timer`(name[, logLevel])	Context manager to log performance data for an arbitrary block of code.

Attributes Documentation

canMultiprocess: ClassVar[bool] = True¶: Whether this task can be run by an executor that uses subprocesses for parallelism.

Methods Documentation

copyCalibSourceFields(calibType, schemaMapper, calibCat, sourceCat, fieldsToCopy)¶

Match sources in a calibrationCat and a sourceCat and copy fields.

The fields copied are those specified by config.icSourceFieldsToCopy if calibType is icSource or config.astromFieldsToCopy if calibType is astrometry.

Parameters:

calibTypestr: The type of calibration: either icSource or astrometry.
calibCatlsst.afw.table.SourceCatalog: Catalog from which to copy fields.
sourceCatlsst.afw.table.SourceCatalog: Catalog to which to copy fields.

Raises:

RuntimeError: Raised if any of the following occur: - calibSchema and calibSourceKeys are not specified. - calibCat and sourceCat are not specified. - calibFieldsToCopy is empty.

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: Get the full name of the task.

getTaskDict() → dict[str, weakref.ReferenceType[lsst.pipe.base.task.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.

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.

recordMaskedPixelFractions(exposure)¶

Record the fraction of all the pixels in an exposure that are masked with a given flag. Each fraction is recorded in the task metadata. One record per flag type.

Parameters:

exposurelsst.afw.image.ExposureF: The target exposure to calculate masked pixel fractions for.

run(exposure, background=None, icSourceCat=None, idGenerator=None)¶

Calibrate an exposure.

Parameters:

exposurelsst.afw.image.ExposureF: Exposure to calibrate.
backgroundlsst.afw.math.BackgroundList, optional: Initial model of background already subtracted from exposure.
icSourceCatlsst.afw.image.SourceCatalog, optional: SourceCatalog from CharacterizeImageTask from which we can copy some fields.
idGeneratorlsst.meas.base.IdGenerator, optional: Object that generates source IDs and provides RNG seeds.

Returns:

resultlsst.pipe.base.Struct

Results as a struct with attributes:

exposure: Characterized exposure (lsst.afw.image.ExposureF).
sourceCat: Detected sources (lsst.afw.table.SourceCatalog).
outputBackground: Model of subtracted background (lsst.afw.math.BackgroundList).
astromMatches: List of source/ref matches from astrometry solver.
matchMeta: Metadata from astrometry matches.
outputExposure: Another reference to exposure for compatibility.
outputCat: Another reference to sourceCat for compatibility.

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.

setMetadata(exposure, photoRes=None)¶

Set task and exposure metadata.

Logs a warning continues if needed data is missing.

Parameters:

exposurelsst.afw.image.ExposureF: Exposure to set metadata on.
photoReslsst.pipe.base.Struct, optional: Result of running photoCal task.

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.
logLevelint: A logging level constant.

Navigation

CalibrateTask¶