MatchBackgroundsTask¶

class lsst.pipe.tasks.matchBackgrounds.MatchBackgroundsTask(*args, **kwargs)¶

Bases: PipelineTask

Match the backgrounds of a list of warped exposures to a reference

Attributes:

configMatchBackgroundsConfig: Configuration for this task.
statsCtrlStatisticsControl: Statistics control object.

Notes

This task is a part of the background subtraction pipeline. It matches the backgrounds of a list of warped science exposures to that of a reference image.

Attributes Summary

canMultiprocess

Methods Summary

`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.
`matchBackgrounds`(warps, skyMap, refVisitId)	Match science visit's background level to that of reference visit
`run`(warps, skyMap)	Match the backgrounds of a list of warped exposures to the same patches in a reference visit
`runQuantum`(butlerQC, inputRefs, outputRefs)	Do butler IO and transform 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

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.

matchBackgrounds(warps, skyMap, refVisitId)¶

Match science visit’s background level to that of reference visit

Process creates binned images of the full focal plane (in tract coordinates) for all visit IDs, subtracts each from a similarly binned FFP reference image, then generates TractBackground objects.

The TractBackground objects representing the difference image backgrounds are then used to generate ‘offset’ images for each warp comprising the full science exposure visit, which are then added to each warp to match the background to that of the reference visit at the warp’s location within the tract.

Best practice uses psf_matched_warp images without the detections mask plane set. When using direct_warp, sources may bias the difference image background estimation. Mask planes are set in TractBackgroundConfig.

Fit diagnostics are also calculated and returned.

Parameters:

warpslist`[`~lsst.daf.butler.DeferredDatasetHandle]: List of warped exposures (of type ExposureF). This is ordered by patch ID, then by visit ID
skyMaplsst.skyMap.SkyMap: SkyMap for deriving the patch/tract dimensions.
refVisitIdint: Chosen reference visit ID to match to.

Returns:

backgroundInfoListlist`[`TractBackground]: List of all difference image backgrounds used to match to reference visit warps, in nanojanskies.
matchedImageListlist`[`~lsst.afw.image.ExposureF]: List of all background-matched warps, in nanojanskies.

run(warps, skyMap)¶

Match the backgrounds of a list of warped exposures to the same patches in a reference visit

A reference visit ID will be chosen automatically if none is supplied.

Parameters:

warpslist`[`~lsst.afw.image.Exposure]: List of warped science exposures to be background-matched.
skyMaplsst.skyMap.SkyMap: SkyMap for deriving the patch/tract dimensions.

Returns:

resultBackgroundList, Exposure: Differential background models and associated background-matched images.

runQuantum(butlerQC: QuantumContext, inputRefs: InputQuantizedConnection, outputRefs: OutputQuantizedConnection) → None¶

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.

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

MatchBackgroundsTask¶