ProcessBrightStarsTask¶
- class lsst.pipe.tasks.processBrightStars.ProcessBrightStarsTask(initInputs=None, *args, **kwargs)¶
Bases:
PipelineTask
Extract bright star cutouts; normalize and warp to the same pixel grid.
This task is used to extract, process, and store small image cut-outs (or “postage stamps”) around bright stars. It relies on three methods, called in succession:
extractStamps
Find bright stars within the exposure using a reference catalog and extract a stamp centered on each.
warpStamps
Shift and warp each stamp to remove optical distortions and sample all stars on the same pixel grid.
measureAndNormalize
Compute the flux of an object in an annulus and normalize it. This is required to normalize each bright star stamp as their central pixels are likely saturated and/or contain ghosts, and cannot be used.
Attributes Summary
Methods Summary
applySkyCorr
(calexp, skyCorr)Apply sky correction to the input exposure.
Empty (clear) the metadata for this Task and all sub-Tasks.
extractStamps
(inputExposure[, filterName, ...])Identify the positions of bright stars within an input exposure using a reference catalog and extract them.
Get metadata for all tasks.
Get the task name as a hierarchical name including parent task names.
getName
()Get the name of the task.
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.run
(inputExposure[, refObjLoader, dataId, ...])Identify bright stars within an exposure using a reference catalog, extract stamps around each, then preprocess them.
runQuantum
(butlerQC, inputRefs, outputRefs)Do butler IO and transform to provide in memory objects for tasks
run
method.Compute (model) stamp size depending on provided buffer value.
timer
(name[, logLevel])Context manager to log performance data for an arbitrary block of code.
warpStamps
(stamps, pixCenters)Warps and shifts all given stamps so they are sampled on the same pixel grid and centered on the central pixel.
Attributes Documentation
Methods Documentation
- applySkyCorr(calexp, skyCorr)¶
Apply sky correction to the input exposure.
Sky corrections can be generated using the
SkyCorrectionTask
. As the sky model generated via that task extends over the full focal plane, this should produce a more optimal sky subtraction solution.- Parameters:
- calexp
Exposure
orMaskedImage
Calibrated exposure to correct.
- skyCorr
BackgroundList
Full focal plane sky correction from
SkyCorrectionTask
.
- calexp
Notes
This method modifies the input
calexp
in-place.
- extractStamps(inputExposure, filterName='phot_g_mean', refObjLoader=None, inputBrightStarStamps=None)¶
Identify the positions of bright stars within an input exposure using a reference catalog and extract them.
- Parameters:
- inputExposure
ExposureF
The image to extract bright star stamps from.
- filterName
str
, optional Name of the camera filter to use for reference catalog filtering.
- refObjLoader
ReferenceObjectLoader
, optional Loader to find objects within a reference catalog.
- inputBrightStarStamps:
BrightStarStamps
, optional Provides information about the stars that have already been extracted from the inputExposure in other steps of the pipeline. For example, this is used in theSubtractBrightStarsTask
to avoid extracting stars that already have been extracted when runningProcessBrightStarsTask
to produce brightStarStamps.
- inputExposure
- Returns:
- getFullMetadata() TaskMetadata ¶
Get metadata for all tasks.
- Returns:
- metadata
TaskMetadata
The keys are the full task name. Values are metadata for the top-level task and all subtasks, sub-subtasks, etc.
- metadata
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:
- fullName
str
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”.
- fullName
- getName() str ¶
Get the name of the task.
- Returns:
- taskName
str
Name of the task.
- taskName
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:
- taskDict
dict
Dictionary containing full task name: task object for the top-level task and all subtasks, sub-subtasks, etc.
- taskDict
- classmethod makeField(doc: str) ConfigurableField ¶
Make a
lsst.pex.config.ConfigurableField
for this task.- Parameters:
- doc
str
Help text for the field.
- doc
- Returns:
- configurableField
lsst.pex.config.ConfigurableField
A
ConfigurableField
for this task.
- configurableField
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:
- name
str
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
.
- name
Notes
The subtask must be defined by
Task.config.name
, an instance ofConfigurableField
orRegistryField
.
- run(inputExposure, refObjLoader=None, dataId=None, skyCorr=None)¶
Identify bright stars within an exposure using a reference catalog, extract stamps around each, then preprocess them.
Bright star preprocessing steps are: shifting, warping and potentially rotating them to the same pixel grid; computing their annular flux, and; normalizing them.
- Parameters:
- inputExposure
ExposureF
The image from which bright star stamps should be extracted.
- refObjLoader
ReferenceObjectLoader
, optional Loader to find objects within a reference catalog.
- dataId
dict
orDataCoordinate
The dataId of the exposure (including detector) that bright stars should be extracted from.
- skyCorr
BackgroundList
, optional Full focal plane sky correction obtained by
SkyCorrectionTask
.
- inputExposure
- Returns:
- brightStarResults
Struct
Results as a struct with attributes:
brightStarStamps
- brightStarResults
- runQuantum(butlerQC, inputRefs, outputRefs)¶
Do butler IO and transform to provide in memory objects for tasks
run
method.- Parameters:
- butlerQC
QuantumContext
A butler which is specialized to operate in the context of a
lsst.daf.butler.Quantum
.- inputRefs
InputQuantizedConnection
Datastructure whose attribute names are the names that identify connections defined in corresponding
PipelineTaskConnections
class. The values of these attributes are thelsst.daf.butler.DatasetRef
objects associated with the defined input/prerequisite connections.- outputRefs
OutputQuantizedConnection
Datastructure whose attribute names are the names that identify connections defined in corresponding
PipelineTaskConnections
class. The values of these attributes are thelsst.daf.butler.DatasetRef
objects associated with the defined output connections.
- butlerQC
- setModelStamp()¶
Compute (model) stamp size depending on provided buffer value.
- timer(name: str, logLevel: int = 10) Iterator[None] ¶
Context manager to log performance data for an arbitrary block of code.
- Parameters:
See also
lsst.utils.timer.logInfo
Implementation function.
Examples
Creating a timer context:
with self.timer("someCodeToTime"): pass # code to time
- warpStamps(stamps, pixCenters)¶
Warps and shifts all given stamps so they are sampled on the same pixel grid and centered on the central pixel. This includes rotating the stamp depending on detector orientation.
- Parameters:
- stamps
Sequence
[ExposureF
] Image cutouts centered on a single object.
- pixCenters
Sequence
[Point2D
] Positions of each object’s center (from the refCat) in pixels.
- stamps
- Returns:
- result
Struct
Results as a struct with attributes:
warpedStars
- Stamps of warped stars.
(
list
[MaskedImage
])
warpTransforms
The corresponding Transform from the initial star stamp to the common model grid.
xy0s
Coordinates of the bottom-left pixels of each stamp, before rotation.
nb90Rots
The number of 90 degrees rotations required to compensate for detector orientation.
(
int
)
- result