lsst.ip.diffim.utils.DipoleTestImage Class Reference

Public Member Functions
	__init__ (self, w=101, h=101, xcenPos=[27.], ycenPos=[25.], xcenNeg=[23.], ycenNeg=[25.], psfSigma=2., flux=[30000.], fluxNeg=None, noise=10., gradientParams=None)
	fitDipoleSource (self, source, **kwds)
	detectDipoleSources (self, doMerge=True, diffim=None, detectSigma=5.5, grow=3, minBinSize=32)

Public Attributes
	w
	h
	xcenPos
	ycenPos
	xcenNeg
	ycenNeg
	psfSigma
	flux
	fluxNeg
	noise
	gradientParams
	diffim
	posImage
	posCatalog
	negImage

Protected Member Functions
	_makeDipoleImage (self)
	_makeStarImage (self, xc=[15.3], yc=[18.6], flux=[2500], schema=None, randomSeed=None)

Detailed Description

Utility class for dipole measurement testing.

Generate an image with simulated dipoles and noise; store the original
"pre-subtraction" images and catalogs as well.
Used to generate test data for DMTN-007 (http://dmtn-007.lsst.io).

Definition at line 709 of file utils.py.

Constructor & Destructor Documentation

__init__()

lsst.ip.diffim.utils.DipoleTestImage.__init__	(		self,
			w = 101,
			h = 101,
			xcenPos = [27.],
			ycenPos = [25.],
			xcenNeg = [23.],
			ycenNeg = [25.],
			psfSigma = 2.,
			flux = [30000.],
			fluxNeg = None,
			noise = 10.,
			gradientParams = None )

Definition at line 717 of file utils.py.

                 psfSigma=2., flux=[30000.], fluxNeg=None, noise=10., gradientParams=None):
        self.w = w
        self.h = h
        self.xcenPos = xcenPos
        self.ycenPos = ycenPos
        self.xcenNeg = xcenNeg
        self.ycenNeg = ycenNeg
        self.psfSigma = psfSigma
        self.flux = flux
        self.fluxNeg = fluxNeg
        if fluxNeg is None:
            self.fluxNeg = self.flux
        self.noise = noise
        self.gradientParams = gradientParams
        self._makeDipoleImage()
 

Member Function Documentation

_makeDipoleImage()

lsst.ip.diffim.utils.DipoleTestImage._makeDipoleImage ( self )

protected

Generate an exposure and catalog with the given dipole source(s).

Definition at line 734 of file utils.py.

    def _makeDipoleImage(self):
        """Generate an exposure and catalog with the given dipole source(s).
        """
        # Must seed the pos/neg images with different values to ensure they get different noise realizations
        posImage, posCatalog = self._makeStarImage(
            xc=self.xcenPos, yc=self.ycenPos, flux=self.flux, randomSeed=111)
 
        negImage, negCatalog = self._makeStarImage(
            xc=self.xcenNeg, yc=self.ycenNeg, flux=self.fluxNeg, randomSeed=222)
 
        dipole = posImage.clone()
        di = dipole.getMaskedImage()
        di -= negImage.getMaskedImage()
 
        self.diffim, self.posImage, self.posCatalog, self.negImage, self.negCatalog \
            = dipole, posImage, posCatalog, negImage, negCatalog
 

_makeStarImage()

lsst.ip.diffim.utils.DipoleTestImage._makeStarImage ( self, xc = [15.3], yc = [18.6], flux = [2500], schema = None, randomSeed = None )

protected

Generate an exposure and catalog with the given stellar source(s).

Definition at line 751 of file utils.py.

    def _makeStarImage(self, xc=[15.3], yc=[18.6], flux=[2500], schema=None, randomSeed=None):
        """Generate an exposure and catalog with the given stellar source(s).
        """
        from lsst.meas.base.tests import TestDataset
        bbox = geom.Box2I(geom.Point2I(0, 0), geom.Point2I(self.w - 1, self.h - 1))
        dataset = TestDataset(bbox, psfSigma=self.psfSigma, threshold=1.)
 
        for i in range(len(xc)):
            dataset.addSource(instFlux=flux[i], centroid=geom.Point2D(xc[i], yc[i]))
 
        if schema is None:
            schema = TestDataset.makeMinimalSchema()
        exposure, catalog = dataset.realize(noise=self.noise, schema=schema, randomSeed=randomSeed)
 
        if self.gradientParams is not None:
            y, x = np.mgrid[:self.w, :self.h]
            gp = self.gradientParams
            gradient = gp[0] + gp[1]*x + gp[2]*y
            if len(self.gradientParams) > 3:  # it includes a set of 2nd-order polynomial params
                gradient += gp[3]*x*y + gp[4]*x*x + gp[5]*y*y
            imgArr = exposure.image.array
            imgArr += gradient
 
        return exposure, catalog
 

detectDipoleSources()

lsst.ip.diffim.utils.DipoleTestImage.detectDipoleSources	(		self,
			doMerge = True,
			diffim = None,
			detectSigma = 5.5,
			grow = 3,
			minBinSize = 32 )

Utility function for detecting dipoles.

Detect pos/neg sources in the diffim, then merge them. A
bigger "grow" parameter leads to a larger footprint which
helps with dipole measurement for faint dipoles.

Parameters
----------
doMerge : `bool`
   Whether to merge the positive and negagive detections into a single
   source table.
diffim : `lsst.afw.image.exposure.exposure.ExposureF`
   Difference image on which to perform detection.
detectSigma : `float`
   Threshold for object detection.
grow : `int`
   Number of pixels to grow the footprints before merging.
minBinSize : `int`
   Minimum bin size for the background (re)estimation (only applies if
   the default leads to min(nBinX, nBinY) < fit order so the default
   config parameter needs to be decreased, but not to a value smaller
   than ``minBinSize``, in which case the fitting algorithm will take
   over and decrease the fit order appropriately.)

Returns
-------
sources : `lsst.afw.table.SourceCatalog`
   If doMerge=True, the merged source catalog is returned OR
detectTask : `lsst.meas.algorithms.SourceDetectionTask`
schema : `lsst.afw.table.Schema`
   If doMerge=False, the source detection task and its schema are
   returned.

Definition at line 781 of file utils.py.

    def detectDipoleSources(self, doMerge=True, diffim=None, detectSigma=5.5, grow=3, minBinSize=32):
        """Utility function for detecting dipoles.
 
        Detect pos/neg sources in the diffim, then merge them. A
        bigger "grow" parameter leads to a larger footprint which
        helps with dipole measurement for faint dipoles.
 
        Parameters
        ----------
        doMerge : `bool`
           Whether to merge the positive and negagive detections into a single
           source table.
        diffim : `lsst.afw.image.exposure.exposure.ExposureF`
           Difference image on which to perform detection.
        detectSigma : `float`
           Threshold for object detection.
        grow : `int`
           Number of pixels to grow the footprints before merging.
        minBinSize : `int`
           Minimum bin size for the background (re)estimation (only applies if
           the default leads to min(nBinX, nBinY) < fit order so the default
           config parameter needs to be decreased, but not to a value smaller
           than ``minBinSize``, in which case the fitting algorithm will take
           over and decrease the fit order appropriately.)
 
        Returns
        -------
        sources : `lsst.afw.table.SourceCatalog`
           If doMerge=True, the merged source catalog is returned OR
        detectTask : `lsst.meas.algorithms.SourceDetectionTask`
        schema : `lsst.afw.table.Schema`
           If doMerge=False, the source detection task and its schema are
           returned.
        """
        if diffim is None:
            diffim = self.diffim
 
        # Start with a minimal schema - only the fields all SourceCatalogs need
        schema = afwTable.SourceTable.makeMinimalSchema()
 
        # Customize the detection task a bit (optional)
        detectConfig = measAlg.SourceDetectionConfig()
        detectConfig.returnOriginalFootprints = False  # should be the default
 
        # code from imageDifference.py:
        detectConfig.thresholdPolarity = "both"
        detectConfig.thresholdValue = detectSigma
        # detectConfig.nSigmaToGrow = psfSigma
        detectConfig.reEstimateBackground = True  # if False, will fail often for faint sources on gradients?
        detectConfig.thresholdType = "pixel_stdev"
        detectConfig.excludeMaskPlanes = ["EDGE"]
        # Test images are often quite small, so may need to adjust background binSize
        while ((min(diffim.getWidth(), diffim.getHeight()))//detectConfig.background.binSize
               < detectConfig.background.approxOrderX and detectConfig.background.binSize > minBinSize):
            detectConfig.background.binSize = max(minBinSize, detectConfig.background.binSize//2)
 
        # Create the detection task. We pass the schema so the task can declare a few flag fields
        detectTask = measAlg.SourceDetectionTask(schema, config=detectConfig)
 
        table = afwTable.SourceTable.make(schema)
        catalog = detectTask.run(table, diffim)
 
        # Now do the merge.
        if doMerge:
            fpSet = catalog.positive
            fpSet.merge(catalog.negative, grow, grow, False)
            sources = afwTable.SourceCatalog(table)
            fpSet.makeSources(sources)
 
            return sources
 
        else:
            return detectTask, schema
 
 

fitDipoleSource()

lsst.ip.diffim.utils.DipoleTestImage.fitDipoleSource	(		self,
			source,
		**	kwds )

Definition at line 776 of file utils.py.

    def fitDipoleSource(self, source, **kwds):
        alg = DipoleFitAlgorithm(self.diffim, self.posImage, self.negImage)
        fitResult = alg.fitDipole(source, **kwds)
        return fitResult
 

Member Data Documentation

diffim

lsst.ip.diffim.utils.DipoleTestImage.diffim

Definition at line 748 of file utils.py.

flux

lsst.ip.diffim.utils.DipoleTestImage.flux

Definition at line 726 of file utils.py.

fluxNeg

lsst.ip.diffim.utils.DipoleTestImage.fluxNeg

Definition at line 727 of file utils.py.

gradientParams

lsst.ip.diffim.utils.DipoleTestImage.gradientParams

Definition at line 731 of file utils.py.

h

lsst.ip.diffim.utils.DipoleTestImage.h

Definition at line 720 of file utils.py.

negImage

lsst.ip.diffim.utils.DipoleTestImage.negImage

Definition at line 748 of file utils.py.

noise

lsst.ip.diffim.utils.DipoleTestImage.noise

Definition at line 730 of file utils.py.

posCatalog

lsst.ip.diffim.utils.DipoleTestImage.posCatalog

Definition at line 748 of file utils.py.

posImage

lsst.ip.diffim.utils.DipoleTestImage.posImage

Definition at line 748 of file utils.py.

psfSigma

lsst.ip.diffim.utils.DipoleTestImage.psfSigma

Definition at line 725 of file utils.py.

w

lsst.ip.diffim.utils.DipoleTestImage.w

Definition at line 719 of file utils.py.

xcenNeg

lsst.ip.diffim.utils.DipoleTestImage.xcenNeg

Definition at line 723 of file utils.py.

xcenPos

lsst.ip.diffim.utils.DipoleTestImage.xcenPos

Definition at line 721 of file utils.py.

ycenNeg

lsst.ip.diffim.utils.DipoleTestImage.ycenNeg

Definition at line 724 of file utils.py.

ycenPos

lsst.ip.diffim.utils.DipoleTestImage.ycenPos

Definition at line 722 of file utils.py.

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The documentation for this class was generated from the following file:

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-8.0.0/Linux64/ip_diffim/g1470d8bcf6+190ad2ba91/python/lsst/ip/diffim/utils.py