BrighterFatterKernelSolveTask

BrighterFatterKernelSolveTask inverts the covariance matrix from a photon transfer curve dataset to produce a brighter-fatter kernel.

Processing summary

BrighterFatterKernelSolveTask runs these operations:

  1. Scale and normalize the covariance matrix.
  2. Tile the covariance matrix to produce the cross-correlation in all four quadrants.
  3. Invert cross-correlation through successive over relaxation process.
  4. Optionally average the per-amplifier kernels into a per-detector kernel.

Python API summary

from lsst.cp.pipe.makeBrighterFatterKernel import BrighterFatterKernelSolveTask
classBrighterFatterKernelSolveTask(*, config: Optional[PipelineTaskConfig] = None, log: Optional[Union[logging.Logger, LsstLogAdapter]] = None, initInputs: Optional[Dict[str, Any]] = None, **kwargs)

Measure appropriate Brighter-Fatter Kernel from the PTC dataset...

attributeconfig

Access configuration fields and retargetable subtasks.

methodrun(inputPtc, dummy, camera, inputDims)

Combine covariance information from PTC into brighter-fatter kernels...

See also

See the BrighterFatterKernelSolveTask API reference for complete details.

Retargetable subtasks

No subtasks.

Configuration fields

connections

Data type
lsst.pipe.base.config.Connections
Field type
ConfigField
Configurations describing the connections of the PipelineTask to datatypes

correlationModelRadius

Default
100
Field type
int Field
Build a model of the correlation coefficients for radii larger than this value in pixels?

correlationModelSlope

Default
-1.35
Field type
float Field
Slope of the correlation model for radii larger than correlationModelRadius

correlationQuadraticFit

Default
False
Field type
bool Field
Use a quadratic fit to find the correlations instead of simple averaging?

eLevelSuccessiveOverRelaxation

Default
5e-14
Field type
float Field
The target residual error for the successive over-relaxation method

forceZeroSum

Default
False
Field type
bool Field
Force the correlation matrix to have zero sum by adjusting the (0,0) value?

ignoreAmpsForAveraging

Default
[]
Field type
str ListField
List of amp names to ignore when averaging the amplifier kernels into the detector kernel. Only relevant for level = DETECTOR

level

Default
'AMP'
Field type
str ChoiceField (optional)
Choices
'AMP'
Every amplifier treated separately
'DETECTOR'
One kernel per detector
None
Field is optional
The level at which to calculate the brighter-fatter kernels

maxIterSuccessiveOverRelaxation

Default
10000
Field type
int Field
The maximum number of iterations allowed for the successive over-relaxation method

nSigmaClip

Default
5
Field type
float Field
Number of sigma to clip when calculating means for the cross-correlation

saveLogOutput

Default
True
Field type
bool Field
Flag to enable/disable saving of log output for a task, enabled by default.

saveMetadata

Default
True
Field type
bool Field
Flag to enable/disable metadata saving for a task, enabled by default.

useAmatrix

Default
False
Field type
bool Field
Use the PTC ‘a’ matrix (Astier et al. 2019 equation 20) instead of the average of measured covariances?

xcorrCheckRejectLevel

Default
2.0
Field type
float Field
Rejection level for the sum of the input cross-correlations. Arrays which sum to greater than this are discarded before the clipped mean is calculated.