lsst.ip.diffim
13.0-26-g703d095+11
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Base class for Psf Matching; should not be called directly. More...
Public Member Functions | |
def | __init__ |
Create the psf-matching Task. More... | |
Public Attributes | |
kConfig | |
useRegularization | |
hMat | |
Static Public Attributes | |
ConfigClass = PsfMatchConfig | |
Private Member Functions | |
def | _diagnostic |
Provide logging diagnostics on quality of spatial kernel fit. More... | |
def | _displayDebug |
Provide visualization of the inputs and ouputs to the Psf-matching code. More... | |
def | _createPcaBasis |
Create Principal Component basis. More... | |
def | _buildCellSet |
Fill a SpatialCellSet with KernelCandidates for the Psf-matching process; override in derived classes. More... | |
def | _solve |
Solve for the PSF matching kernel. More... | |
Static Private Attributes | |
string | _DefaultName = "psfMatch" |
Base class for Psf Matching; should not be called directly.
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PsfMatchTask is a base class that implements the core functionality for matching the Psfs of two images using a spatially varying Psf-matching lsst.afw.math.LinearCombinationKernel. The Task requires the user to provide an instance of an lsst.afw.math.SpatialCellSet, filled with lsst.ip.diffim.KernelCandidate instances, and a list of lsst.afw.math.Kernels of basis shapes that will be used for the decomposition. If requested, the Task also performs background matching and returns the differential background model as an lsst.afw.math.Kernel.SpatialFunction.
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Create the psf-matching Task.
*args | arguments to be passed to lsst.pipe.base.task.Task.__init__ |
**kwargs | keyword arguments to be passed to lsst.pipe.base.task.Task.__init__ |
The initialization sets the Psf-matching kernel configuration using the value of self.config.kernel.active. If the kernel is requested with regularization to moderate the bias/variance tradeoff, currently only used when a delta function kernel basis is provided, it creates a regularization matrix stored as member variable self.hMat.
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As a base class, this Task is not directly invoked. However, run() methods that are implemented on derived classes will make use of the core _solve() functionality, which defines a sequence of lsst.afw.math.CandidateVisitor classes that iterate through the KernelCandidates, first building up a per-candidate solution and then building up a spatial model from the ensemble of candidates. Sigma clipping is performed using the mean and standard deviation of all kernel sums (to reject variable objects), on the per-candidate substamp diffim residuals (to indicate a bad choice of kernel basis shapes for that particular object), and on the substamp diffim residuals using the spatial kernel fit (to indicate a bad choice of spatial kernel order, or poor constraints on the spatial model). The _diagnostic() method logs information on the quality of the spatial fit, and also modifies the Task metadata.
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See PsfMatchConfig, PsfMatchConfigAL, PsfMatchConfigDF, and DetectionConfig.
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Kernel sum (10^{-0.4 * Δ zeropoint}) of the spatial Psf-matching kernel; via PsfMatchTask._diagnostic
If using sum-of-Gaussian basis, the kernel size; via generateAlardLuptonBasisList
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The command line task interface supports a flag -d/–debug
to import debug.py from your PYTHONPATH
. The relevant contents of debug.py for this Task include:
Note that if you want addional logging info, you may add to your scripts:
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As a base class, there is no example code for PsfMatchTask. However, see ImagePsfMatchTask, SnapPsfMatchTask, and ModelPsfMatchTask.
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Definition at line 528 of file psfMatch.py.
def lsst.ip.diffim.psfMatch.PsfMatchTask.__init__ | ( | self, | |
args, | |||
kwargs | |||
) |
Create the psf-matching Task.
*args | arguments to be passed to lsst.pipe.base.task.Task.__init__ |
**kwargs | keyword arguments to be passed to lsst.pipe.base.task.Task.__init__ |
The initialization sets the Psf-matching kernel configuration using the value of self.config.kernel.active. If the kernel is requested with regularization to moderate the bias/variance tradeoff, currently only used when a delta function kernel basis is provided, it creates a regularization matrix stored as member variable self.hMat.
Definition at line 679 of file psfMatch.py.
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private |
Fill a SpatialCellSet with KernelCandidates for the Psf-matching process; override in derived classes.
Definition at line 888 of file psfMatch.py.
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private |
Create Principal Component basis.
If a principal component analysis is requested, typically when using a delta function basis, perform the PCA here and return a new basis list containing the new principal components.
kernelCellSet,: | a SpatialCellSet containing KernelCandidates, from which components are derived |
nStarPerCell,: | the number of stars per cell to visit when doing the PCA |
policy,: | input policy controlling the single kernel visitor |
Definition at line 834 of file psfMatch.py.
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private |
Provide logging diagnostics on quality of spatial kernel fit.
kernelCellSet,: | Cellset that contains the KernelCandidates used in the fitting |
spatialSolution,: | KernelSolution of best-fit |
spatialKernel,: | Best-fit spatial Kernel model |
spatialBg,: | Best-fit spatial background model |
Definition at line 703 of file psfMatch.py.
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private |
Provide visualization of the inputs and ouputs to the Psf-matching code.
kernelCellSet,: | the SpatialCellSet used in determining the matching kernel and background |
spatialKernel,: | spatially varying Psf-matching kernel |
spatialBackground,: | spatially varying background-matching function |
Definition at line 788 of file psfMatch.py.
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private |
Solve for the PSF matching kernel.
kernelCellSet,: | a SpatialCellSet to use in determining the matching kernel (typically as provided by _buildCellSet) |
basisList,: | list of Kernels to be used in the decomposition of the spatially varying kernel (typically as provided by makeKernelBasisList) |
returnOnExcept,: | if True then return (None, None) if an error occurs, else raise the exception |
Raise Exception if unable to determine PSF matching kernel and returnOnExcept False
Definition at line 894 of file psfMatch.py.
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staticprivate |
Definition at line 677 of file psfMatch.py.
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static |
Definition at line 676 of file psfMatch.py.
lsst.ip.diffim.psfMatch.PsfMatchTask.hMat |
Definition at line 701 of file psfMatch.py.
lsst.ip.diffim.psfMatch.PsfMatchTask.kConfig |
Definition at line 692 of file psfMatch.py.
lsst.ip.diffim.psfMatch.PsfMatchTask.useRegularization |
Definition at line 696 of file psfMatch.py.