PhotonTransferCurveExtractTask¶
PhotonTransferCurveExtractTask
constructs a photon transfer curve (PTC) dataset from a single pair of flat field exposures.
Processing summary¶
PhotonTransferCurveExtractTask
runs these operations:
Pairs exposures together by either exposure time (the default) or by exposure id (in the case where the exposure time does not track with the observed flux).
Measures the mean, variances, and covariances from the difference of the pair of exposures.
Persists these results in a set of partial PTC datasets.
Python API summary¶
from lsst.cp.pipe.ptc.cpPtcExtract import PhotonTransferCurveExtractTask
-
class
PhotonTransferCurveExtractTask
(*, config=None, log=None, initInputs=None, **kwargs) Task to measure covariances from flat fields
...
- attributeconfig
Access configuration fields and retargetable subtasks.
-
method
run
(inputExp, inputDims, inputPhotodiodeData=None) Measure covariances from difference of flat pairs
...
See also
See the PhotonTransferCurveExtractTask
API reference for complete details.
Retargetable subtasks¶
No subtasks.
Configuration fields¶
auxiliaryHeaderKeys¶
Auxiliary header keys to store with the PTC dataset.
binSize¶
Bin the image by this factor in both dimensions.
connections¶
- Data type
lsst.pipe.base.config.PhotonTransferCurveExtractConfigConnections
- Field type
Configurations describing the connections of the PipelineTask to datatypes
detectorMeasurementRegion¶
- Default
'AMP'
- Field type
str
ChoiceField
(optional)- Choices
'AMP'
Amplifier of the detector.
'FULL'
Full image.
None
Field is optional
Region of each exposure where to perform the calculations (amplifier or full image).
doExtractPhotodiodeData¶
Extract photodiode data?
doGain¶
Calculate a gain per input flat pair.
doKsHistMeasurement¶
Do the Ks test of gaussianity? If False, kspValue will be filled with all 1.0s.
doVignetteFunctionRegionSelection¶
Use vignette function to select PTC region?
edgeMaskLevel¶
- Default
'DETECTOR'
- Field type
str
ChoiceField
(optional)- Choices
'DETECTOR'
Mask only the edges of the full detector.
'AMP'
Mask edges of each amplifier.
None
Field is optional
Mask edge pixels in which coordinate frame: DETECTOR or AMP?
efdPhotodiodeSeries¶
EFD series to use to get photodiode values.
efdSalIndex¶
EFD SAL Index to select electrometer. This is 101 for mainTel, 201 for auxTel.
gainCorrectionType¶
- Default
'FULL'
- Field type
str
ChoiceField
(optional)- Choices
'NONE'
No correction.
'SIMPLE'
First order correction.
'FULL'
Second order correction.
None
Field is optional
Correction type for the gain.
ksHistLimitMultiplier¶
Number of sigma (as predicted from the mean value) to compute KS test histogram.
ksHistMinDataValues¶
Minimum number of good data values to compute KS test histogram.
ksHistNBins¶
Number of bins for the KS test histogram.
maskNameList¶
Mask list to exclude from statistics calculations.
matchExposuresByFluxKeyword¶
Header keyword for flux if matchExposuresType is FLUX.
matchExposuresType¶
- Default
'TIME'
- Field type
str
ChoiceField
(optional)- Choices
'TIME'
Match exposures by reported exposure time. Entries that are within 5e-3 seconds.
'FLUX'
Match exposures by target flux. Use header keyword in matchExposuresByFluxKeyword to find the flux.
'EXPID'
Match exposures by exposure ID.
None
Field is optional
Match input exposures by time, flux, or expId
maximumRangeCovariancesAstier¶
Maximum range of covariances as in Astier+19
minNumberGoodPixelsForCovariance¶
Minimum number of acceptable good pixels per amp to calculate the covariances (via FFT or direclty).
nIterSigmaClipPtc¶
Number of sigma-clipping iterations for afwMath.StatisticsControl()
nSigmaClipPtc¶
Sigma cut for afwMath.StatisticsControl()
numEdgeSuspect¶
Number of edge pixels to be flagged as untrustworthy.
photodiodeCurrentScale¶
Scale factor to apply to photodiode current values for the CHARGE_SUM
, TRIMMED_SUM
, and MEAN
integration methods.
photodiodeIntegrationMethod¶
- Default
'TRIMMED_SUM'
- Field type
str
ChoiceField
(optional)- Choices
'DIRECT_SUM'
Use numpy’s trapezoid integrator on all photodiode readout entries
'TRIMMED_SUM'
Use numpy’s trapezoid integrator, clipping the leading and trailing entries, which are nominally at zero baseline level.
'CHARGE_SUM'
Treat the current values as integrated charge over the sampling interval and simply sum the values, after subtracting a baseline level.
'MEAN'
{‘Take the average of the photodiode measurements and multiply by the exposure time.’}
None
Field is optional
Integration method for photodiode monitoring data.
saveLogOutput¶
Flag to enable/disable saving of log output for a task, enabled by default.
thresholdDiffAfwVarVsCov00¶
If the absolute fractional differece between afwMath.VARIANCECLIP and Cov00 for a region of a difference image is greater than this threshold (percentage), a warning will be issued.
useEfdPhotodiodeData¶
Extract photodiode values from EFD?
vignetteFunctionPolynomialCoeffs¶
Polynomial terms for radial vignetting function. This is used with vig = np.polyval(coeffs, radius), where radius is in meters. This must be set if doVignetteFunctionRegionSelection is True.
vignetteFunctionRegionSelectionMinimumPixels¶
Minumum number of pixels to select for vignette function region selection.
vignetteFunctionRegionSelectionPercent¶
Vignetting function variation over the focal plane that is determined to be satisfactory. If this does not yield vignetteFunctionRegionSelectionMinimumPixels then this will be increased until vignetteFunctionRegionSelectionMinimumPixels is reached.