CharacterizeImageTask¶
- class lsst.pipe.tasks.characterizeImage.CharacterizeImageTask(schema=None, **kwargs)¶
Bases:
PipelineTask
Measure bright sources and use this to estimate background and PSF of an exposure.
Given an exposure with defects repaired (masked and interpolated over, e.g. as output by
IsrTask
): - detect and measure bright sources - repair cosmic rays - detect and mask streaks - measure and subtract background - measure PSF- Parameters:
- schema
lsst.afw.table.Schema
, optional Initial schema for icSrc catalog.
- **kwargs
Additional keyword arguments.
- schema
Notes
Debugging: CharacterizeImageTask has a debug dictionary with the following keys:
- frame
int: if specified, the frame of first debug image displayed (defaults to 1)
- repair_iter
bool; if True display image after each repair in the measure PSF loop
- background_iter
bool; if True display image after each background subtraction in the measure PSF loop
- measure_iter
bool; if True display image and sources at the end of each iteration of the measure PSF loop See
displayAstrometry
for the meaning of the various symbols.- psf
bool; if True display image and sources after PSF is measured; this will be identical to the final image displayed by measure_iter if measure_iter is true
- repair
bool; if True display image and sources after final repair
- measure
bool; if True display image and sources after final measurement
Attributes Summary
Methods Summary
detectMeasureAndEstimatePsf
(exposure, ...)Perform one iteration of detect, measure, and estimate PSF.
display
(itemName, exposure[, sourceCat])Display exposure and sources on next frame (for debugging).
Empty (clear) the metadata for this Task and all sub-Tasks.
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
(exposure[, background, idGenerator])Characterize a science image.
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
Methods Documentation
- detectMeasureAndEstimatePsf(exposure, idGenerator, background)¶
Perform one iteration of detect, measure, and estimate PSF.
Performs the following operations:
if config.doMeasurePsf or not exposure.hasPsf():
install a simple PSF model (replacing the existing one, if need be)
interpolate over cosmic rays with keepCRs=True
estimate background and subtract it from the exposure
detect, deblend and measure sources, and subtract a refined background model;
- if config.doMeasurePsf:
measure PSF
- Parameters:
- exposure
lsst.afw.image.ExposureF
Exposure to characterize.
- idGenerator
lsst.meas.base.IdGenerator
Object that generates source IDs and provides RNG seeds.
- background
lsst.afw.math.BackgroundList
, optional Initial model of background already subtracted from exposure.
- exposure
- Returns:
- result
lsst.pipe.base.Struct
Results as a struct with attributes:
exposure
Characterized exposure (
lsst.afw.image.ExposureF
).sourceCat
Detected sources (
lsst.afw.table.SourceCatalog
).background
Model of subtracted background (
lsst.afw.math.BackgroundList
).psfCellSet
Spatial cells of PSF candidates (
lsst.afw.math.SpatialCellSet
).
- result
- Raises:
- LengthError
Raised if there are too many CR pixels.
- display(itemName, exposure, sourceCat=None)¶
Display exposure and sources on next frame (for debugging).
- Parameters:
- itemName
str
Name of item in
debugInfo
.- exposure
lsst.afw.image.ExposureF
Exposure to display.
- sourceCat
lsst.afw.table.SourceCatalog
, optional Catalog of sources detected on the exposure.
- itemName
- 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(exposure, background=None, idGenerator=None)¶
Characterize a science image.
Peforms the following operations: - Iterate the following config.psfIterations times, or once if config.doMeasurePsf false:
detect and measure sources and estimate PSF (see detectMeasureAndEstimatePsf for details)
interpolate over cosmic rays
perform final measurement
- Parameters:
- exposure
lsst.afw.image.ExposureF
Exposure to characterize.
- background
lsst.afw.math.BackgroundList
, optional Initial model of background already subtracted from exposure.
- idGenerator
lsst.meas.base.IdGenerator
, optional Object that generates source IDs and provides RNG seeds.
- exposure
- Returns:
- result
lsst.pipe.base.Struct
Results as a struct with attributes:
exposure
Characterized exposure (
lsst.afw.image.ExposureF
).sourceCat
Detected sources (
lsst.afw.table.SourceCatalog
).background
Model of subtracted background (
lsst.afw.math.BackgroundList
).psfCellSet
Spatial cells of PSF candidates (
lsst.afw.math.SpatialCellSet
).characterized
Another reference to
exposure
for compatibility.backgroundModel
Another reference to
background
for compatibility.
- result
- Raises:
- RuntimeError
Raised if PSF sigma is NaN.
- 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