LinearitySolveTask¶
LinearitySolveTask constructs a linearity correction model (a Linearizer) based on the results stored in the input photon transfer curve (PTC) dataset.
Processing summary¶
LinearitySolveTask runs these operations:
Convert the input exposure time/photodiode flux measurement to a proxy flux by fitting the low-flux end with a linear fit.
Perform fit against using the observed flux and this linear proxy flux (using either a spline or a polynomial).
Store the correction, such that the corrected flux is equal to the uncorrected flux + the linearity correction as a function of the uncorrected flux.
Python API summary¶
from lsst.cp.pipe.cpLinearitySolve import LinearitySolveTask
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class
LinearitySolveTask(*, config=None, log=None, initInputs=None, **kwargs) Fit the linearity from the PTC dataset
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- attributeconfig
Access configuration fields and retargetable subtasks.
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method
run(inputPtc, dummy, camera, inputDims, inputPhotodiodeCorrection=None) Fit non-linearity to PTC data, returning the correct Linearizer object
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See also
See the LinearitySolveTask API reference for complete details.
Retargetable subtasks¶
No subtasks.
Configuration fields¶
applyPhotodiodeCorrection¶
Calculate and apply a correction to the photodiode readings?
connections¶
- Data type
lsst.pipe.base.config.LinearitySolveConfigConnections- Field type
Configurations describing the connections of the PipelineTask to datatypes
doSplineFitOffset¶
Fit a scattered light offset in the spline fit.
doSplineFitTemperature¶
Fit temperature coefficient in spline fit?
doSplineFitWeights¶
Fit linearity weight parameters in the spline fit.
ignorePtcMask¶
Ignore the expIdMask set by the PTC solver?
linearityType¶
- Default
'Squared'- Field type
strChoiceField(optional)- Choices
'LookupTable'Create a lookup table solution.
'Polynomial'Create an arbitrary polynomial solution.
'Squared'Create a single order squared solution.
'Spline'Create a spline based solution.
'None'Create a dummy solution.
NoneField is optional
Type of linearizer to construct.
maxLinearAdu¶
Maximum DN value to use to estimate linear term.
maxLookupTableAdu¶
Maximum DN value for a LookupTable linearizer.
minLinearAdu¶
Minimum DN value to use to estimate linear term.
minPhotodiodeCurrent¶
Minimum value to trust photodiode signals.
nSigmaClipLinear¶
Maximum deviation from linear solution for Poissonian noise.
polynomialOrder¶
- Default
3- Field type
- Range
[2,inf)
Degree of polynomial to fit. Must be at least 2.
saveLogOutput¶
Flag to enable/disable saving of log output for a task, enabled by default.
splineFitMaxIter¶
Maximum number of iterations for spline fit.
splineFitMaxRejectionPerIteration¶
Maximum number of rejections per iteration for spline fit.
splineFitMinIter¶
Minimum number of iterations for spline fit.
splineFitTemperatureColumn¶
Name of the temperature column to use when fitting temperature coefficients in spline fit; this must not be None if doSplineFitTemperature is True.
splineFitWeightParsStart¶
Starting parameters for weight fit, if doSplineFitWeights=True. Parameters are such that sigma = sqrt(par[0]**2. + par[1]**2./mu).If doSplineFitWeights=False then these are used as-is; otherwise they are used as the initial values for fitting these parameters.
splineGroupingColumn¶
Column to use for grouping together points for Spline mode, to allow for different proportionality constants. If not set, no grouping will be done.
splineGroupingMinPoints¶
Minimum number of linearity points to allow grouping together points for Spline mode with splineGroupingColumn. This configuration is here to prevent misuse of the Spline code to avoid over-fitting.
splineKnots¶
Number of spline knots to use in fit.
trimmedState¶
Will this linearizer be used on trimmed data?
usePhotodiode¶
Use the photodiode info instead of the raw expTimes?