Inheritance diagram for lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask:

Public Member Functions
	__init__ (self, **kwargs)

	runQuantum (self, butlerQC, inputRefs, outputRefs)

	run (self, template, science, sources, visitSummary=None)

	chooseConvolutionMethod (self, template, science)

	runMakeKernel (self, template, science, sources=None, convolveTemplate=True, runSourceDetection=False)

	runKernelSourceDetection (self, template, science)

	runConvolveTemplate (self, template, science, psfMatchingKernel, backgroundModel=None)

	runConvolveScience (self, template, science, psfMatchingKernel, backgroundModel=None)

	finalize (self, template, science, difference, kernel, templateMatched=True, preConvMode=False, preConvKernel=None, spatiallyVarying=False)

	updateMasks (self, template, science)

Public Attributes
	convolutionControl = lsst.afw.math.ConvolutionControl()

	templatePsfSize

	log

	sciencePsfSize = getPsfFwhm(science.psf)

Static Public Attributes
	ConfigClass = AlardLuptonSubtractConfig

Protected Member Functions
	_applyExternalCalibrations (self, exposure, visitSummary)

	_calculateMagLim (self, exposure, nsigma=5.0, fallbackPsfSize=None)

	_convolveExposure (self, exposure, kernel, convolutionControl, bbox=None, psf=None, photoCalib=None, interpolateBadMaskPlanes=False)

	_sourceSelector (self, template, science, sources, fallback=False, preconvolved=False)

	_prepareInputs (self, template, science, visitSummary=None)

	_clearMask (self, mask, clearMaskPlanes=None)

Static Protected Member Functions
	_validateExposures (template, science)

	_renameMaskPlanes (mask, maskPlane, newMaskPlane)

Static Protected Attributes
str	_DefaultName = "alardLuptonSubtract"

Detailed Description

Compute the image difference of a science and template image using
the Alard & Lupton (1998) algorithm.

Definition at line 343 of file subtractImages.py.

Constructor & Destructor Documentation

◆ init()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.__init__	(		self,
		**	kwargs )

Definition at line 350 of file subtractImages.py.

Member Function Documentation

◆ _applyExternalCalibrations()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._applyExternalCalibrations	(	self,
		exposure,
		visitSummary )

protected

Replace calibrations (psf, and ApCorrMap) on this exposure with
external ones.".

Parameters
----------
exposure : `lsst.afw.image.exposure.Exposure`
    Input exposure to adjust calibrations.
visitSummary : `lsst.afw.table.ExposureCatalog`
    Exposure catalog with external calibrations to be applied. Catalog
    uses the detector id for the catalog id, sorted on id for fast
    lookup.

Returns
-------
exposure : `lsst.afw.image.exposure.Exposure`
    Exposure with adjusted calibrations.

Definition at line 365 of file subtractImages.py.

◆ _calculateMagLim()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._calculateMagLim	(	self,
		exposure,
		nsigma = 5.0,
		fallbackPsfSize = None )

protected

Calculate an exposure's limiting magnitude.

This method uses the photometric zeropoint together with the
PSF size from the average position of the exposure.

Parameters
----------
exposure : `lsst.afw.image.Exposure`
    The target exposure to calculate the limiting magnitude for.
nsigma : `float`, optional
    The detection threshold in sigma.
fallbackPsfSize : `float`, optional
    PSF FWHM to use in the event the exposure PSF cannot be retrieved.

Returns
-------
maglim : `astropy.units.Quantity`
    The limiting magnitude of the exposure, or np.nan.

Definition at line 788 of file subtractImages.py.

◆ _clearMask()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._clearMask	(	self,
		mask,
		clearMaskPlanes = None )

protected

Clear the mask plane of an exposure.

Parameters
----------
mask : `lsst.afw.image.Mask`
    The mask plane to erase, which will be modified in place.
clearMaskPlanes : `list` of `str`, optional
    Erase the specified mask planes.
    If not supplied, the entire mask will be erased.

Definition at line 1154 of file subtractImages.py.

◆ _convolveExposure()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._convolveExposure	(	self,
		exposure,
		kernel,
		convolutionControl,
		bbox = None,
		psf = None,
		photoCalib = None,
		interpolateBadMaskPlanes = False )

protected

Convolve an exposure with the given kernel.

Parameters
----------
exposure : `lsst.afw.Exposure`
    exposure to convolve.
kernel : `lsst.afw.math.LinearCombinationKernel`
    PSF matching kernel computed in the ``makeKernel`` subtask.
convolutionControl : `lsst.afw.math.ConvolutionControl`
    Configuration for convolve algorithm.
bbox : `lsst.geom.Box2I`, optional
    Bounding box to trim the convolved exposure to.
psf : `lsst.afw.detection.Psf`, optional
    Point spread function (PSF) to set for the convolved exposure.
photoCalib : `lsst.afw.image.PhotoCalib`, optional
    Photometric calibration of the convolved exposure.
interpolateBadMaskPlanes : `bool`, optional
    If set, interpolate over mask planes specified in
    ``config.badMaskPlanes`` before convolving the image.

Returns
-------
convolvedExp : `lsst.afw.Exposure`
    The convolved image.

Definition at line 864 of file subtractImages.py.

◆ _prepareInputs()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._prepareInputs	(	self,
		template,
		science,
		visitSummary = None )

protected

Perform preparatory calculations common to all Alard&Lupton Tasks.

Parameters
----------
template : `lsst.afw.image.ExposureF`
    Template exposure, warped to match the science exposure. The
    variance plane of the template image is modified in place.
science : `lsst.afw.image.ExposureF`
    Science exposure to subtract from the template. The variance plane
    of the science image is modified in place.
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.

Definition at line 995 of file subtractImages.py.

◆ _renameMaskPlanes()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._renameMaskPlanes	(	mask,
		maskPlane,
		newMaskPlane )

staticprotected

Rename a mask plane by adding the new name and copying the data.

Parameters
----------
mask : `lsst.afw.image.Mask`
    The mask image to update in place.
maskPlane : `str`
    The name of the existing mask plane to copy.
newMaskPlane : `str`
    The new name of the mask plane that will be added.
    If the mask plane already exists, it will be updated in place.

Definition at line 1136 of file subtractImages.py.

◆ _sourceSelector()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._sourceSelector	(	self,
		template,
		science,
		sources,
		fallback = False,
		preconvolved = False )

protected

Select sources from a catalog that meet the selection criteria.
The selection criteria include any configured parameters of the
`sourceSelector` subtask, as well as checking the science and template
mask planes.

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`
    Input source catalog to select sources from.
fallback : `bool`, optional
    Switch indicating the source selector is being called after
    running the fallback source detection subtask, which does not run a
    full set of measurement plugins and can't use the same settings for
    the source selector.
preconvolved : `bool`, optional
    If set, exclude a wider buffer around the edge of the image to
    account for an extra convolution.

Returns
-------
kernelSources : `lsst.afw.table.SourceCatalog`
    The input source catalog, with flagged and low signal-to-noise
    sources removed and footprints added.

Raises
------
InsufficientKernelSourcesError
    An AlgorithmError that is raised if there are not enough PSF
    candidates to construct the PSF matching kernel.

Definition at line 912 of file subtractImages.py.

◆ _validateExposures()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._validateExposures	(		template,
			science )

staticprotected

Check that the WCS of the two Exposures match, the template bbox
contains the science bbox, and that the bands match.

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.

Raises
------
AssertionError
    Raised if the WCS of the template is not equal to the science WCS,
    if the science image is not fully contained in the template
    bounding box, or if the bands do not match.

Definition at line 835 of file subtractImages.py.

◆ chooseConvolutionMethod()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.chooseConvolutionMethod	(	self,
		template,
		science )

Determine whether the template should be convolved with the PSF
matching kernel.

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.

Returns
-------
convolveTemplate : `bool`
    Convolve the template to match the two images?

Raises
------
RuntimeError
    If an unsupported convolution mode is supplied.

Definition at line 486 of file subtractImages.py.

◆ finalize()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.finalize	(	self,
		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?

Returns
-------
correctedExposure : `lsst.afw.image.ExposureF`
    The decorrelated image difference.

Definition at line 739 of file subtractImages.py.

◆ run()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.run	(	self,
		template,
		science,
		sources,
		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.
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.

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.
    ``kernelSources` : `lsst.afw.table.SourceCatalog`
        Sources from the input catalog that were used to construct the
        PSF-matching kernel.

Reimplemented in lsst.ip.diffim.subtractImages.AlardLuptonPreconvolveSubtractTask, and lsst.ip.diffim.subtractImages.SimplifiedSubtractTask.

Definition at line 419 of file subtractImages.py.

◆ runConvolveScience()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.runConvolveScience	(	self,
		template,
		science,
		psfMatchingKernel,
		backgroundModel = None )

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.
psfMatchingKernel : `lsst.afw.math.Kernel`
    Kernel to be used to PSF-match the science image to the template.
backgroundModel : `lsst.afw.math.Function2D`, optional
    Background model that was fit while solving for the PSF-matching
    kernel.

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.

Definition at line 676 of file subtractImages.py.

◆ runConvolveTemplate()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.runConvolveTemplate	(	self,
		template,
		science,
		psfMatchingKernel,
		backgroundModel = None )

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.
psfMatchingKernel : `lsst.afw.math.Kernel`
    Kernel to be used to PSF-match the science image to the template.
backgroundModel : `lsst.afw.math.Function2D`, optional
    Background model that was fit while solving for the PSF-matching
    kernel.

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.

Definition at line 628 of file subtractImages.py.

◆ runKernelSourceDetection()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.runKernelSourceDetection	(	self,
		template,
		science )

Run detection on the science image and use the template mask plane
to reject candidate sources.

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.

Returns
-------
kernelSources : `lsst.afw.table.SourceCatalog`
        Sources from the input catalog to use to construct the
        PSF-matching kernel.

Definition at line 597 of file subtractImages.py.

◆ runMakeKernel()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.runMakeKernel	(	self,
		template,
		science,
		sources = None,
		convolveTemplate = True,
		runSourceDetection = False )

Construct the PSF-matching kernel.

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.
    Not used if ``runSourceDetection`` is set.
convolveTemplate : `bool`, optional
    Construct the matching kernel to convolve the template?
runSourceDetection : `bool`, optional
    Run a minimal version of source detection to determine kernel
    candidates? If False, a source list to select kernel candidates
    from must be supplied.

Returns
-------
results : `lsst.pipe.base.Struct`
    ``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.
    ``kernelSources` : `lsst.afw.table.SourceCatalog`
        Sources from the input catalog that were used to construct the
        PSF-matching kernel.

Definition at line 530 of file subtractImages.py.

◆ runQuantum()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.runQuantum	(	self,
		butlerQC,
		inputRefs,
		outputRefs )

Definition at line 406 of file subtractImages.py.

◆ updateMasks()

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.updateMasks	(	self,
		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.

Definition at line 1091 of file subtractImages.py.

Member Data Documentation

◆ _DefaultName

str lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._DefaultName = "alardLuptonSubtract"

staticprotected

Definition at line 348 of file subtractImages.py.

◆ ConfigClass

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.ConfigClass = AlardLuptonSubtractConfig

static

Definition at line 347 of file subtractImages.py.

◆ convolutionControl

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.convolutionControl = lsst.afw.math.ConvolutionControl()

Definition at line 359 of file subtractImages.py.

◆ log

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.log

Definition at line 586 of file subtractImages.py.

◆ sciencePsfSize

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.sciencePsfSize = getPsfFwhm(science.psf)

Definition at line 1050 of file subtractImages.py.

◆ templatePsfSize

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.templatePsfSize

Definition at line 513 of file subtractImages.py.

The documentation for this class was generated from the following file:

python/lsst/ip/diffim/subtractImages.py

Public Member Functions

Public Attributes

Static Public Attributes

Protected Member Functions

Static Protected Member Functions

Static Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ __init__()

Member Function Documentation

◆ _applyExternalCalibrations()

◆ _calculateMagLim()

◆ _clearMask()

◆ _convolveExposure()

◆ _prepareInputs()

◆ _renameMaskPlanes()

◆ _sourceSelector()

◆ _validateExposures()

◆ chooseConvolutionMethod()

◆ finalize()

◆ run()

◆ runConvolveScience()

◆ runConvolveTemplate()

◆ runKernelSourceDetection()

◆ runMakeKernel()

◆ runQuantum()

◆ updateMasks()

Member Data Documentation

◆ _DefaultName

◆ ConfigClass

◆ convolutionControl

◆ log

◆ sciencePsfSize

◆ templatePsfSize

◆ init()