AlardLuptonSubtractTask¶
- class lsst.ip.diffim.AlardLuptonSubtractTask(**kwargs)¶
Bases:
PipelineTask
Compute the image difference of a science and template image using the Alard & Lupton (1998) algorithm.
Attributes Summary
Methods Summary
Empty (clear) the metadata for this Task and all sub-Tasks.
finalize
(template, science, difference, kernel)Decorrelate the difference image to undo the noise correlations caused by convolution.
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
(template, science, sources[, ...])PSF match, subtract, and decorrelate two images.
runConvolveScience
(template, science, ...)Convolve the science image with a PSF-matching kernel and subtract the template image.
runConvolveTemplate
(template, science, ...)Convolve the template image with a PSF-matching kernel and subtract from the 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.
updateMasks
(template, science)Update the science and template mask planes before differencing.
Attributes Documentation
Methods Documentation
- finalize(template, science, difference, kernel, templateMatched=True, preConvMode=False, preConvKernel=None, spatiallyVarying=False)¶
Decorrelate the difference image to undo the noise correlations caused by convolution.
- Parameters:
- template
lsst.afw.image.ExposureF
Template exposure, warped to match the science exposure.
- science
lsst.afw.image.ExposureF
Science exposure to subtract from the template.
- difference
lsst.afw.image.ExposureF
Result of subtracting template and science.
- kernel
lsst.afw.math.Kernel
An (optionally spatially-varying) PSF matching kernel
- templateMatched
bool
, optional Was the template PSF-matched to the science image?
- preConvMode
bool
, optional Was the science image preconvolved with its own PSF before PSF matching the template?
- preConvKernel
lsst.afw.detection.Psf
, optional If not
None
, then the science image was pre-convolved with (the reflection of) this kernel. Must be normalized to sum to 1.- spatiallyVarying
bool
, optional Compute the decorrelation kernel spatially varying across the image?
- template
- Returns:
- correctedExposure
lsst.afw.image.ExposureF
The decorrelated image difference.
- correctedExposure
- 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(template, science, sources, finalizedPsfApCorrCatalog=None, visitSummary=None)¶
PSF match, subtract, and decorrelate two images.
- Parameters:
- template
lsst.afw.image.ExposureF
Template exposure, warped to match the science exposure.
- science
lsst.afw.image.ExposureF
Science exposure to subtract from the template.
- sources
lsst.afw.table.SourceCatalog
Identified sources on the science exposure. This catalog is used to select sources in order to perform the AL PSF matching on stamp images around them.
- finalizedPsfApCorrCatalog
lsst.afw.table.ExposureCatalog
, optional Exposure catalog with finalized psf models and aperture correction maps to be applied. Catalog uses the detector id for the catalog id, sorted on id for fast lookup. Deprecated in favor of
visitSummary
, and will be removed after v26.- visitSummary
lsst.afw.table.ExposureCatalog
, optional Exposure catalog with external calibrations to be applied. Catalog uses the detector id for the catalog id, sorted on id for fast lookup. Ignored (for temporary backwards compatibility) if
finalizedPsfApCorrCatalog
is provided.
- template
- Returns:
- results
lsst.pipe.base.Struct
difference
lsst.afw.image.ExposureF
Result of subtracting template and science.
matchedTemplate
lsst.afw.image.ExposureF
Warped and PSF-matched template exposure.
backgroundModel
lsst.afw.math.Function2D
Background model that was fit while solving for the PSF-matching kernel
psfMatchingKernel
lsst.afw.math.Kernel
Kernel used to PSF-match the convolved image.
- results
- Raises:
- RuntimeError
If an unsupported convolution mode is supplied.
- RuntimeError
If there are too few sources to calculate the PSF matching kernel.
- lsst.pipe.base.NoWorkFound
Raised if fraction of good pixels, defined as not having NO_DATA set, is less then the configured requiredTemplateFraction
- runConvolveScience(template, science, selectSources)¶
Convolve the science image with a PSF-matching kernel and subtract the template image.
- Parameters:
- template
lsst.afw.image.ExposureF
Template exposure, warped to match the science exposure.
- science
lsst.afw.image.ExposureF
Science exposure to subtract from the template.
- selectSources
lsst.afw.table.SourceCatalog
Identified sources on the science exposure. This catalog is used to select sources in order to perform the AL PSF matching on stamp images around them.
- template
- Returns:
- results
lsst.pipe.base.Struct
difference
lsst.afw.image.ExposureF
Result of subtracting template and science.
matchedTemplate
lsst.afw.image.ExposureF
Warped template exposure. Note that in this case, the template is not PSF-matched to the science image.
backgroundModel
lsst.afw.math.Function2D
Background model that was fit while solving for the PSF-matching kernel
psfMatchingKernel
lsst.afw.math.Kernel
Kernel used to PSF-match the science image to the template.
- results
- runConvolveTemplate(template, science, selectSources)¶
Convolve the template image with a PSF-matching kernel and subtract from the science image.
- Parameters:
- template
lsst.afw.image.ExposureF
Template exposure, warped to match the science exposure.
- science
lsst.afw.image.ExposureF
Science exposure to subtract from the template.
- selectSources
lsst.afw.table.SourceCatalog
Identified sources on the science exposure. This catalog is used to select sources in order to perform the AL PSF matching on stamp images around them.
- template
- Returns:
- results
lsst.pipe.base.Struct
difference
lsst.afw.image.ExposureF
Result of subtracting template and science.
matchedTemplate
lsst.afw.image.ExposureF
Warped and PSF-matched template exposure.
backgroundModel
lsst.afw.math.Function2D
Background model that was fit while solving for the PSF-matching kernel
psfMatchingKernel
lsst.afw.math.Kernel
Kernel used to PSF-match the template to the science image.
- results
- runQuantum(butlerQC: QuantumContext, inputRefs: InputQuantizedConnection, outputRefs: OutputQuantizedConnection) None ¶
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
- 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
- updateMasks(template, science)¶
Update the science and template mask planes before differencing.
- Parameters:
- template
lsst.afw.image.Exposure
Template exposure, warped to match the science exposure. The template mask planes will be erased, except for a few specified in the task config.
- science
lsst.afw.image.Exposure
Science exposure to subtract from the template. The DETECTED and DETECTED_NEGATIVE mask planes of the science image will be erased.
- template