DecorrelateALKernelSpatialTask

Pipe-task that removes the neighboring-pixel covariance in an image difference that are added when the template image is convolved with the Alard-Lupton PSF matching kernel.

Description

This task is a simple wrapper around DecorrelateALKernelTask, which takes a spatiallyVarying parameter in its run method. If it is False, then it simply calls the run method of DecorrelateALKernelTask. If it is True, then it uses the ImageMapReduceTask framework to break the exposures into subExposures on a grid, and performs the run method of DecorrelateALKernelTask on each subExposure. This enables it to account for spatially-varying PSFs and noise in the exposures when performing the decorrelation.

This task has no standalone example, however it is applied as a subtask of ImageDifferenceTask. There is also an example of its use in tests/testImageDecorrelation.py.

Python API summary

from lsst.ip.diffim.imageDecorrelation import DecorrelateALKernelSpatialTask
classDecorrelateALKernelSpatialTask(*args, **kwargs)

Decorrelate the effect of convolution by Alard-Lupton matching kernel in image difference...

attributeconfig

Access configuration fields and retargetable subtasks.

methodrun(scienceExposure, templateExposure, subtractedExposure, psfMatchingKernel, spatiallyVarying=True, preConvKernel=None, templateMatched=True, preConvMode=False)

Perform decorrelation of an image difference exposure...

See also

See the DecorrelateALKernelSpatialTask API reference for complete details.

Retargetable subtasks

No subtasks.

Configuration fields

decorrelateConfig

Data type

lsst.ip.diffim.imageDecorrelation.DecorrelateALKernelConfig

Field type

ConfigField

DecorrelateALKernel config to use when running on complete exposure (non spatially-varying)

decorrelateMapReduceConfig

Data type

lsst.ip.diffim.imageDecorrelation.DecorrelateALKernelMapReduceConfig

Field type

ConfigField

DecorrelateALKernelMapReduce config to use when running on each sub-image (spatially-varying)

ignoreMaskPlanes

Default
('INTRP', 'EDGE', 'DETECTED', 'SAT', 'CR', 'BAD', 'NO_DATA', 'DETECTED_NEGATIVE')
Field type

str ListField

Mask planes to ignore for sigma-clipped statistics