ImageDifferenceTask¶
Python API summary¶
from lsst.pipe.tasks.imageDifference import ImageDifferenceTask
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class
ImageDifferenceTask Subtract an image from a template and measure the result
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attribute
config Access configuration fields and retargetable subtasks.
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method
runDataRef Subtract an image from a template coadd and measure the result
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See also
See the ImageDifferenceTask API reference for complete details.
Retargetable subtasks¶
astrometer¶
- Default
lsst.meas.astrom.astrometry.AstrometryTask- Field type
astrometry task; used to match sources to reference objects, but not to fit a WCS
decorrelate¶
- Default
lsst.ip.diffim.imageDecorrelation.DecorrelateALKernelSpatialTask- Field type
Decorrelate effects of A&L kernel convolution on image difference, only if doSubtract is True. If this option is enabled, then detection.thresholdValue should be set to 5.0 (rather than the default of 5.5).
detection¶
- Default
lsst.meas.algorithms.detection.SourceDetectionTask- Field type
Low-threshold detection for final measurement
evalLocCalib¶
- Default
lsst.meas.base.evaluateLocalCalibration.EvaluateLocalCalibrationTask- Field type
Task to strip calibrations from an exposure and store their local values in the output DiaSource catalog.
getTemplate¶
- Default
lsst.ip.diffim.getTemplate.GetCoaddAsTemplateTask- Field type
Subtask to retrieve template exposure and sources
measurement¶
- Default
lsst.ip.diffim.dipoleFitTask.DipoleFitTask- Field type
Enable updated dipole fitting method
refObjLoader¶
- Default
lsst.meas.algorithms.loadIndexedReferenceObjects.LoadIndexedReferenceObjectsTask- Field type
reference object loader
scaleVariance¶
- Default
- Field type
Subtask to rescale the variance of the template to the statistically expected level
sourceSelector¶
- Default
lsst.meas.algorithms.objectSizeStarSelector.ObjectSizeStarSelectorTask- Field type
Source selection algorithm
subtract¶
- Default
'al'- Field type
Single-selection
RegistryField- Choices
'al'lsst.ip.diffim.imagePsfMatch.ImagePsfMatchTask'zogy'lsst.ip.diffim.zogy.ZogyImagePsfMatchTask
Subtraction Algorithm
Configuration fields¶
controlStepSize¶
What step size (every Nth one) to select a control sample from the kernelSources
diaSourceMatchRadius¶
Match radius (in arcseconds) for DiaSource to Source association
doAddCalexpBackground¶
Add background to calexp before processing it. Useful as ipDiffim does background matching.
doAddMetrics¶
Add columns to the source table to hold analysis metrics?
doDecorrelation¶
Perform diffim decorrelation to undo pixel correlation due to A&L kernel convolution? If True, also update the diffim PSF.
doEvalLocCalibration¶
Store calibration products (local wcs and photoCalib) in the output DiaSource catalog.
doMatchSources¶
Match diaSources with input calexp sources and ref catalog sources
doMerge¶
Merge positive and negative diaSources with grow radius set by growFootprint
doPreConvolve¶
Convolve science image by its PSF before PSF-matching?
doScaleTemplateVariance¶
Scale variance of the template before PSF matching
doSelectDcrCatalog¶
Select stars of extreme color as part of the control sample
doSelectVariableCatalog¶
Select stars that are variable to be part of the control sample
doSpatiallyVarying¶
If using Zogy or A&L decorrelation, perform these on a grid across the image in order to allow for spatial variations
doUseRegister¶
Use image-to-image registration to align template with science image
doWriteMatchedExp¶
Write warped and PSF-matched template coadd exposure?
growFootprint¶
Grow positive and negative footprints by this amount before merging
kernelSourcesFromRef¶
Select sources to measure kernel from reference catalog if True, template if false
templateSipOrder¶
Sip Order for fitting the Template Wcs (default is too high, overfitting)