lsst.ip.diffim ga085b1478a+1393071258
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Public Member Functions | Public Attributes | Static Public Attributes | Protected Member Functions | Static Protected Member Functions | Static Protected Attributes | List of all members
lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask Class Reference
Inheritance diagram for lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask:
lsst.ip.diffim.subtractImages.AlardLuptonPreconvolveSubtractTask

Public Member Functions

def __init__ (self, **kwargs)
 
def run (self, template, science, sources, finalizedPsfApCorrCatalog=None)
 
def runConvolveTemplate (self, template, science, selectSources)
 
def runConvolveScience (self, template, science, selectSources)
 
def finalize (self, template, science, difference, kernel, templateMatched=True, preConvMode=False, preConvKernel=None, spatiallyVarying=False)
 

Public Attributes

 convolutionControl
 

Static Public Attributes

AlardLuptonSubtractConfig ConfigClass = AlardLuptonSubtractConfig
 

Protected Member Functions

def _applyExternalCalibrations (self, exposure, finalizedPsfApCorrCatalog)
 
def _sourceSelector (self, sources, mask)
 
def _prepareInputs (self, template, science, finalizedPsfApCorrCatalog=None)
 

Static Protected Member Functions

def _validateExposures (template, science)
 
def _convolveExposure (exposure, kernel, convolutionControl, bbox=None, psf=None, photoCalib=None)
 
def _checkMask (mask, sources, badMaskPlanes)
 

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 191 of file subtractImages.py.

Constructor & Destructor Documentation

◆ __init__()

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

Definition at line 198 of file subtractImages.py.

Member Function Documentation

◆ _applyExternalCalibrations()

def lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._applyExternalCalibrations (   self,
  exposure,
  finalizedPsfApCorrCatalog 
)
protected
Replace calibrations (psf, and ApCorrMap) on this exposure with external ones.".

Parameters
----------
exposure : `lsst.afw.image.exposure.Exposure`
    Input exposure to adjust calibrations.
finalizedPsfApCorrCatalog : `lsst.afw.table.ExposureCatalog`
    Exposure catalog with finalized psf models and aperture correction
    maps to be applied if config.doApplyFinalizedPsf=True.  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 211 of file subtractImages.py.

◆ _checkMask()

def lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._checkMask (   mask,
  sources,
  badMaskPlanes 
)
staticprotected
Exclude sources that are located on masked pixels.

Parameters
----------
mask : `lsst.afw.image.Mask`
    The image mask plane to use to reject sources
    based on the location of their centroid on the ccd.
sources : `lsst.afw.table.SourceCatalog`
    The source catalog to evaluate.
badMaskPlanes : `list` of `str`
    List of the names of the mask planes to exclude.

Returns
-------
flags : `numpy.ndarray` of `bool`
    Array indicating whether each source in the catalog should be
    kept (True) or rejected (False) based on the value of the
    mask plane at its location.

Definition at line 633 of file subtractImages.py.

◆ _convolveExposure()

def lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._convolveExposure (   exposure,
  kernel,
  convolutionControl,
  bbox = None,
  psf = None,
  photoCalib = None 
)
staticprotected
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.

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

Definition at line 550 of file subtractImages.py.

◆ _prepareInputs()

def lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._prepareInputs (   self,
  template,
  science,
  finalizedPsfApCorrCatalog = 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.
finalizedPsfApCorrCatalog : `lsst.afw.table.ExposureCatalog`, optional
    Exposure catalog with finalized psf models and aperture correction
    maps to be applied if config.doApplyFinalizedPsf=True.  Catalog uses
    the detector id for the catalog id, sorted on id for fast lookup.

Definition at line 661 of file subtractImages.py.

◆ _sourceSelector()

def lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._sourceSelector (   self,
  sources,
  mask 
)
protected
Select sources from a catalog that meet the selection criteria.

Parameters
----------
sources : `lsst.afw.table.SourceCatalog`
    Input source catalog to select sources from.
mask : `lsst.afw.image.Mask`
    The image mask plane to use to reject sources
    based on their location on the ccd.

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

Raises
------
RuntimeError
    If there are too few sources to compute the PSF matching kernel
    remaining after source selection.

Definition at line 589 of file subtractImages.py.

◆ _validateExposures()

def lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask._validateExposures (   template,
  science 
)
staticprotected
Check that the WCS of the two Exposures match, and the template bbox
contains the science bbox.

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,
    or if the science image is not fully contained in the template
    bounding box.

Definition at line 523 of file subtractImages.py.

◆ finalize()

def 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 471 of file subtractImages.py.

◆ run()

def lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.run (   self,
  template,
  science,
  sources,
  finalizedPsfApCorrCatalog = 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 if config.doApplyFinalizedPsf=True.  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.

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

Reimplemented in lsst.ip.diffim.subtractImages.AlardLuptonPreconvolveSubtractTask.

Definition at line 252 of file subtractImages.py.

◆ runConvolveScience()

def lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.runConvolveScience (   self,
  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.

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 406 of file subtractImages.py.

◆ runConvolveTemplate()

def lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.runConvolveTemplate (   self,
  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.

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 353 of file subtractImages.py.

Member Data Documentation

◆ _DefaultName

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

Definition at line 196 of file subtractImages.py.

◆ ConfigClass

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

Definition at line 195 of file subtractImages.py.

◆ convolutionControl

lsst.ip.diffim.subtractImages.AlardLuptonSubtractTask.convolutionControl

Definition at line 205 of file subtractImages.py.


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