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| __init__ (self, modelImages, effectiveWavelength, bandwidth, filterLabel=None, psf=None, bbox=None, wcs=None, mask=None, variance=None, photoCalib=None) |
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| fromImage (cls, maskedImage, dcrNumSubfilters, effectiveWavelength, bandwidth, wcs=None, filterLabel=None, psf=None, photoCalib=None) |
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| fromQuantum (cls, availableCoaddRefs, effectiveWavelength, bandwidth, numSubfilters) |
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| __len__ (self) |
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| __getitem__ (self, subfilter) |
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| __setitem__ (self, subfilter, maskedImage) |
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| effectiveWavelength (self) |
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| filter (self) |
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| bandwidth (self) |
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| psf (self) |
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| bbox (self) |
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| wcs (self) |
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| mask (self) |
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| variance (self) |
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| getReferenceImage (self, bbox=None) |
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| assign (self, dcrSubModel, bbox=None) |
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| buildMatchedTemplate (self, exposure=None, order=3, visitInfo=None, bbox=None, mask=None, splitSubfilters=True, splitThreshold=0., amplifyModel=1.) |
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| buildMatchedExposure (self, exposure=None, visitInfo=None, bbox=None, mask=None) |
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| conditionDcrModel (self, modelImages, bbox, gain=1.) |
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| regularizeModelIter (self, subfilter, newModel, bbox, regularizationFactor, regularizationWidth=2) |
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| regularizeModelFreq (self, modelImages, bbox, statsCtrl, regularizationFactor, regularizationWidth=2, mask=None, convergenceMaskPlanes="DETECTED") |
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| calculateNoiseCutoff (self, image, statsCtrl, bufferSize, convergenceMaskPlanes="DETECTED", mask=None, bbox=None) |
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| applyImageThresholds (self, image, highThreshold=None, lowThreshold=None, regularizationWidth=2) |
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A model of the true sky after correcting chromatic effects.
Attributes
----------
dcrNumSubfilters : `int`
Number of sub-filters used to model chromatic effects within a band.
modelImages : `list` of `lsst.afw.image.Image`
A list of masked images, each containing the model for one subfilter
Notes
-----
The ``DcrModel`` contains an estimate of the true sky, at a higher
wavelength resolution than the input observations. It can be forward-
modeled to produce Differential Chromatic Refraction (DCR) matched
templates for a given ``Exposure``, and provides utilities for conditioning
the model in ``dcrAssembleCoadd`` to avoid oscillating solutions between
iterations of forward modeling or between the subfilters of the model.
Definition at line 32 of file dcrModel.py.
lsst.ip.diffim.dcrModel.DcrModel.applyImageThresholds |
( |
| self, |
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| image, |
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| highThreshold = None, |
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| lowThreshold = None, |
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| regularizationWidth = 2 ) |
Restrict image values to be between upper and lower limits.
This method flags all pixels in an image that are outside of the given
threshold values. The threshold values are taken from a reference
image, so noisy pixels are likely to get flagged. In order to exclude
those noisy pixels, the array of flags is eroded and dilated, which
removes isolated pixels outside of the thresholds from the list of
pixels to be modified. Pixels that remain flagged after this operation
have their values set to the appropriate upper or lower threshold
value.
Parameters
----------
image : `numpy.ndarray`
The image to apply the thresholds to.
The values will be modified in place.
highThreshold : `numpy.ndarray`, optional
Array of upper limit values for each pixel of ``image``.
lowThreshold : `numpy.ndarray`, optional
Array of lower limit values for each pixel of ``image``.
regularizationWidth : `int`, optional
Minimum radius of a region to include in regularization, in pixels.
Definition at line 623 of file dcrModel.py.
lsst.ip.diffim.dcrModel.DcrModel.buildMatchedExposure |
( |
| self, |
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| exposure = None, |
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| visitInfo = None, |
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| bbox = None, |
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| mask = None ) |
Wrapper to create an exposure from a template image.
Parameters
----------
exposure : `lsst.afw.image.Exposure`, optional
The input exposure to build a matched template for.
May be omitted if all of the metadata is supplied separately
visitInfo : `lsst.afw.image.VisitInfo`, optional
Metadata for the exposure. Ignored if ``exposure`` is set.
bbox : `lsst.afw.geom.Box2I`, optional
Sub-region of the coadd, or use the entire coadd if not supplied.
mask : `lsst.afw.image.Mask`, optional
reference mask to use for the template image.
Returns
-------
templateExposure : `lsst.afw.image.exposureF`
The DCR-matched template
Raises
------
RuntimeError
If no `photcCalib` is set.
Definition at line 426 of file dcrModel.py.
lsst.ip.diffim.dcrModel.DcrModel.buildMatchedTemplate |
( |
| self, |
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| exposure = None, |
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| order = 3, |
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| visitInfo = None, |
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| bbox = None, |
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| mask = None, |
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| splitSubfilters = True, |
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| splitThreshold = 0., |
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| amplifyModel = 1. ) |
Create a DCR-matched template image for an exposure.
Parameters
----------
exposure : `lsst.afw.image.Exposure`, optional
The input exposure to build a matched template for.
May be omitted if all of the metadata is supplied separately
order : `int`, optional
Interpolation order of the DCR shift.
visitInfo : `lsst.afw.image.VisitInfo`, optional
Metadata for the exposure. Ignored if ``exposure`` is set.
bbox : `lsst.afw.geom.Box2I`, optional
Sub-region of the coadd, or use the entire coadd if not supplied.
mask : `lsst.afw.image.Mask`, optional
reference mask to use for the template image.
splitSubfilters : `bool`, optional
Calculate DCR for two evenly-spaced wavelengths in each subfilter,
instead of at the midpoint. Default: True
splitThreshold : `float`, optional
Minimum DCR difference within a subfilter required to use
``splitSubfilters``
amplifyModel : `float`, optional
Multiplication factor to amplify differences between model planes.
Used to speed convergence of iterative forward modeling.
Returns
-------
templateImage : `lsst.afw.image.ImageF`
The DCR-matched template
Raises
------
ValueError
If neither ``exposure`` or ``visitInfo`` are set.
Definition at line 358 of file dcrModel.py.
lsst.ip.diffim.dcrModel.DcrModel.fromImage |
( |
| cls, |
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| maskedImage, |
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| dcrNumSubfilters, |
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| effectiveWavelength, |
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| bandwidth, |
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| wcs = None, |
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| filterLabel = None, |
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| psf = None, |
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| photoCalib = None ) |
Initialize a DcrModel by dividing a coadd between the subfilters.
Parameters
----------
maskedImage : `lsst.afw.image.MaskedImage`
Input coadded image to divide equally between the subfilters.
dcrNumSubfilters : `int`
Number of sub-filters used to model chromatic effects within a
band.
effectiveWavelength : `float`
The effective wavelengths of the current filter, in nanometers.
bandwidth : `float`
The bandwidth of the current filter, in nanometers.
wcs : `lsst.afw.geom.SkyWcs`
Coordinate system definition (wcs) for the exposure.
filterLabel : `lsst.afw.image.FilterLabel`, optional
The filter label, set in the current instruments' obs package.
Required for any calculation of DCR, including making matched
templates.
psf : `lsst.afw.detection.Psf`, optional
Point spread function (PSF) of the model.
Required if the ``DcrModel`` will be persisted.
photoCalib : `lsst.afw.image.PhotoCalib`, optional
Calibration to convert instrumental flux and
flux error to nanoJansky.
Returns
-------
dcrModel : `lsst.pipe.tasks.DcrModel`
Best fit model of the true sky after correcting chromatic effects.
Definition at line 67 of file dcrModel.py.
lsst.ip.diffim.dcrModel.DcrModel.fromQuantum |
( |
| cls, |
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| availableCoaddRefs, |
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| effectiveWavelength, |
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| bandwidth, |
|
|
| numSubfilters ) |
Load an existing DcrModel from a Gen 3 repository.
Parameters
----------
availableCoaddRefs : `dict` [`int`, `lsst.daf.butler.DeferredDatasetHandle`]
Dictionary of spatially relevant retrieved coadd patches,
indexed by their sequential patch number.
effectiveWavelength : `float`
The effective wavelengths of the current filter, in nanometers.
bandwidth : `float`
The bandwidth of the current filter, in nanometers.
numSubfilters : `int`
Number of subfilters in the DcrCoadd.
Returns
-------
dcrModel : `lsst.pipe.tasks.DcrModel`
Best fit model of the true sky after correcting chromatic effects.
Definition at line 121 of file dcrModel.py.
lsst.ip.diffim.dcrModel.DcrModel.regularizeModelFreq |
( |
| self, |
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| modelImages, |
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| bbox, |
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| statsCtrl, |
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| regularizationFactor, |
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|
| regularizationWidth = 2, |
|
|
| mask = None, |
|
|
| convergenceMaskPlanes = "DETECTED" ) |
Restrict large variations in the model between subfilters.
Parameters
----------
modelImages : `list` of `lsst.afw.image.Image`
The new DCR model images from the current iteration.
The values will be modified in place.
bbox : `lsst.afw.geom.Box2I`
Sub-region to coadd
statsCtrl : `lsst.afw.math.StatisticsControl`
Statistics control object for coaddition.
regularizationFactor : `float`
Maximum relative change of the model allowed between subfilters.
regularizationWidth : `int`, optional
Minimum radius of a region to include in regularization, in pixels.
mask : `lsst.afw.image.Mask`, optional
Optional alternate mask
convergenceMaskPlanes : `list` of `str`, or `str`, optional
Mask planes to use to calculate convergence.
Notes
-----
This implementation of frequency regularization restricts each
subfilter image to be a smoothly-varying function times a reference
image.
Definition at line 520 of file dcrModel.py.