BrighterFatterKernel

class lsst.ip.isr.BrighterFatterKernel(camera=None, level=None, **kwargs)

Bases: IsrCalib

Calibration of brighter-fatter kernels for an instrument.

ampKernels are the kernels for each amplifier in a detector, as generated by having level == 'AMP'.

detectorKernel is the kernel generated for a detector as a whole, as generated by having level == 'DETECTOR'.

makeDetectorKernelFromAmpwiseKernels is a method to generate the kernel for a detector, constructed by averaging together the ampwise kernels in the detector. The existing application code is only defined for kernels with level == 'DETECTOR', so this method is used if the supplied kernel was built with level == 'AMP'.

Parameters

cameralsst.afw.cameraGeom.Camera

Camera describing detector geometry.

levelstr

Level the kernels will be generated for.

loglogging.Logger, optional

Log to write messages to.

**kwargs :

Parameters to pass to parent constructor.

Notes

Version 1.1 adds the expIdMask property, and substitutes means and variances for rawMeans and rawVariances from the PTC dataset.

expIdMaskdict, [str,`numpy.ndarray`]

Dictionary keyed by amp names containing the mask produced after outlier rejection.

rawMeansdict, [str, numpy.ndarray]

Dictionary keyed by amp names containing the unmasked average of the means of the exposures in each flat pair.

rawVariancesdict, [str, numpy.ndarray]

Dictionary keyed by amp names containing the variance of the difference image of the exposures in each flat pair. Corresponds to rawVars of PTC.

rawXcorrsdict, [str, numpy.ndarray]

Dictionary keyed by amp names containing an array of measured covariances per mean flux. Corresponds to covariances of PTC.

badAmpslist

List of bad amplifiers names.

shapetuple

Tuple of the shape of the BFK kernels.

gaindict, [str,`float`]

Dictionary keyed by amp names containing the fitted gains.

noisedict, [str,`float`]

Dictionary keyed by amp names containing the fitted noise.

meanXcorrsdict, [str,`numpy.ndarray`]

Dictionary keyed by amp names containing the averaged cross-correlations.

validdict, [str,`bool`]

Dictionary keyed by amp names containing validity of data.

ampKernelsdict, [str, numpy.ndarray]

Dictionary keyed by amp names containing the BF kernels.

detKernelsdict

Dictionary keyed by detector names containing the BF kernels.

Methods Summary

fromDict(dictionary)	Construct a calibration from a dictionary of properties.
fromTable(tableList)	Construct calibration from a list of tables.
getLengths()	Return the set of lengths needed for reshaping components.
initFromCamera(camera[, detectorId])	Initialize kernel structure from camera.
makeDetectorKernelFromAmpwiseKernels(...[, ...])	Average the amplifier level kernels to create a detector level kernel.
repackCorrelations(amp, correlationShape)	If the correlations were masked, they need to be repacked into the correct shape.
replaceDetectorKernelWithAmpKernel(ampName, ...)
toDict()	Return a dictionary containing the calibration properties.
toTable()	Construct a list of tables containing the information in this calibration.
updateMetadata([setDate])	Update calibration metadata.

Methods Documentation

classmethod fromDict(dictionary)

Construct a calibration from a dictionary of properties.

Parameters

dictionarydict

Dictionary of properties.

Returns

caliblsst.ip.isr.BrighterFatterKernel

Constructed calibration.

Raises

RuntimeError

Raised if the supplied dictionary is for a different calibration. Raised if the version of the supplied dictionary is 1.0.

classmethod fromTable(tableList)

Construct calibration from a list of tables.

This method uses the fromDict method to create the calibration, after constructing an appropriate dictionary from the input tables.

Parameters

tableListlist [astropy.table.Table]

List of tables to use to construct the brighter-fatter calibration.

Returns

caliblsst.ip.isr.BrighterFatterKernel

The calibration defined in the tables.

getLengths()

Return the set of lengths needed for reshaping components.

Returns

kernelLengthint

Product of the elements of self.shape.

smallLengthint

Size of an untiled covariance.

nObsint

Number of observation pairs used in the kernel.

initFromCamera(camera, detectorId=None)

Initialize kernel structure from camera.

Parameters

cameralsst.afw.cameraGeom.Camera

Camera to use to define geometry.

detectorIdint, optional

Index of the detector to generate.

Returns

caliblsst.ip.isr.BrighterFatterKernel

The initialized calibration.

Raises

RuntimeError

Raised if no detectorId is supplied for a calibration with level='AMP'.

makeDetectorKernelFromAmpwiseKernels(detectorName, ampsToExclude=[])

Average the amplifier level kernels to create a detector level kernel. There is no change in index ordering/orientation from this averaging.

Parameters

detectorNamestr

Detector for which the averaged kernel will be used.

ampsToExcludelist [str], optional

Amps that should not be included in the average.

repackCorrelations(amp, correlationShape)

If the correlations were masked, they need to be repacked into the correct shape.

Parameters

ampstr

Amplifier needing repacked.

correlationShapetuple [int], (3, )

Shape the correlations are expected to take.

replaceDetectorKernelWithAmpKernel(ampName, detectorName)

toDict()

Return a dictionary containing the calibration properties.

The dictionary should be able to be round-tripped through fromDict.

Returns

dictionarydict

Dictionary of properties.

toTable()

Construct a list of tables containing the information in this calibration.

The list of tables should create an identical calibration after being passed to this class’s fromTable method.

Returns

tableListlist [lsst.afw.table.Table]

List of tables containing the crosstalk calibration information.

updateMetadata(setDate=False, **kwargs)

Update calibration metadata.

This calls the base class’s method after ensuring the required calibration keywords will be saved.

Parameters

setDatebool, optional

Update the CALIBDATE fields in the metadata to the current time. Defaults to False.

kwargs :

Other keyword parameters to set in the metadata.