SubtractBackgroundTask¶
- class lsst.meas.algorithms.SubtractBackgroundTask(config: Config | None = None, name: str | None = None, parentTask: Task | None = None, log: logging.Logger | lsst.utils.logging.LsstLogAdapter | None = None)¶
Bases:
Task
Subtract the background from an exposure
Methods Summary
Empty (clear) the metadata for this Task and all sub-Tasks.
fitBackground
(maskedImage[, nx, ny, algorithm])Estimate the background of a masked image
Get schema catalogs for all tasks in the hierarchy, combining the results into a single dict.
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 the schemas generated by this 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
(exposure[, background, stats, statsKeys])Fit and subtract the background of an exposure.
timer
(name[, logLevel])Context manager to log performance data for an arbitrary block of code.
Methods Documentation
- fitBackground(maskedImage, nx=0, ny=0, algorithm=None)¶
Estimate the background of a masked image
- Parameters:
- maskedImage
lsst.afw.image.maskedImage
Masked image whose background is to be computed
- nx‘int`
Number of x bands; if 0 compute from width and
self.config.binSizeX
- ny
int
Number of y bands; if 0 compute from height and
self.config.binSizeY
- algorithm
str
Name of interpolation algorithm; if None use
self.config.algorithm
- maskedImage
- Returns:
- bg
lsst.afw.math.Background
A fit background
- bg
- Raises:
- RuntimeError
Raised if lsst.afw.math.makeBackground returns None, an indicator of failure.
- getAllSchemaCatalogs() Dict[str, Any] ¶
Get schema catalogs for all tasks in the hierarchy, combining the results into a single dict.
- Returns:
- schemacatalogs
dict
Keys are butler dataset type, values are a empty catalog (an instance of the appropriate
lsst.afw.table
Catalog type) for all tasks in the hierarchy, from the top-level task down through all subtasks.
- schemacatalogs
Notes
This method may be called on any task in the hierarchy; it will return the same answer, regardless.
The default implementation should always suffice. If your subtask uses schemas the override
Task.getSchemaCatalogs
, not this method.
- 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
- getSchemaCatalogs() Dict[str, Any] ¶
Get the schemas generated by this task.
- Returns:
- schemaCatalogs
dict
Keys are butler dataset type, values are an empty catalog (an instance of the appropriate
lsst.afw.table
Catalog type) for this task.
- schemaCatalogs
See also
Task.getAllSchemaCatalogs
Notes
Warning
Subclasses that use schemas must override this method. The default implementation returns an empty dict.
This method may be called at any time after the Task is constructed, which means that all task schemas should be computed at construction time, not when data is actually processed. This reflects the philosophy that the schema should not depend on the data.
Returning catalogs rather than just schemas allows us to save e.g. slots for SourceCatalog as well.
- getTaskDict() Dict[str, ReferenceType[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(exposure, background=None, stats=True, statsKeys=None)¶
Fit and subtract the background of an exposure.
- Parameters:
- exposure
lsst.afw.image.Exposure
Exposure whose background is to be subtracted.
- background
lsst.afw.math.BackgroundList
Initial background model already subtracted. May be None if no background has been subtracted.
- stats
bool
If True then measure the mean and variance of the full background model and record the results in the exposure’s metadata.
- statsKeys
tuple
Key names used to store the mean and variance of the background in the exposure’s metadata (another tuple); if None then use (“BGMEAN”, “BGVAR”); ignored if stats is false.
- exposure
- Returns:
- background
lsst.afw.math.BackgroundLst
Full background model (initial model with changes), contained in an
lsst.pipe.base.Struct
.
- background