lsst.meas.deblender.plugins Namespace Reference

Classes
class	DeblenderPlugin

Functions
def	clipFootprintToNonzeroImpl (foot, image)
def	fitPsfs (debResult, log, psfChisqCut1=1.5, psfChisqCut2=1.5, psfChisqCut2b=1.5, tinyFootprintSize=2)
def	buildSymmetricTemplates (debResult, log, patchEdges=False, setOrigTemplate=True)
def	rampFluxAtEdge (debResult, log, patchEdges=False)
def	medianSmoothTemplates (debResult, log, medianFilterHalfsize=2)
def	makeTemplatesMonotonic (debResult, log)
def	clipFootprintsToNonzero (debResult, log)
def	weightTemplates (debResult, log)
def	reconstructTemplates (debResult, log, maxTempDotProd=0.5)
def	apportionFlux (debResult, log, assignStrayFlux=True, strayFluxAssignment='r-to-peak', strayFluxToPointSources='necessary', clipStrayFluxFraction=0.001, getTemplateSum=False)

Function Documentation

apportionFlux()

def lsst.meas.deblender.plugins.apportionFlux	(		debResult,
			log,
			assignStrayFlux = True,
			strayFluxAssignment = 'r-to-peak',
			strayFluxToPointSources = 'necessary',
			clipStrayFluxFraction = 0.001,
			getTemplateSum = False
	)

Apportion flux to all of the peak templates in each filter

Divide the ``maskedImage`` flux amongst all of the templates based
on the fraction of flux assigned to each ``template``.
Leftover "stray flux" is assigned to peaks based on the other parameters.

Parameters
----------
debResult: `lsst.meas.deblender.baseline.DeblenderResult`
    Container for the final deblender results.
log: `log.Log`
    LSST logger for logging purposes.
assignStrayFlux: `bool`, optional
    If True then flux in the parent footprint that is not covered by any
    of the template footprints is assigned to templates based on
    their 1/(1+r^2) distance.
    How the flux is apportioned is determined by ``strayFluxAssignment``.
strayFluxAssignment: `string`, optional
    Determines how stray flux is apportioned.

    * ``trim``: Trim stray flux and do not include in any footprints
    * ``r-to-peak`` (default): Stray flux is assigned based on
      (1/(1+r^2) from the peaks
    * ``r-to-footprint``: Stray flux is distributed to the footprints
      based on 1/(1+r^2) of the minimum distance from the stray flux
      to footprint
    * ``nearest-footprint``: Stray flux is assigned to the footprint
      with lowest L-1 (Manhattan) distance to the stray flux

strayFluxToPointSources: `string`, optional
    Determines how stray flux is apportioned to point sources

    * ``never``: never apportion stray flux to point sources
    * ``necessary`` (default): point sources are included only if there
      are no extended sources nearby
    * ``always``: point sources are always included in
      the 1/(1+r^2) splitting

clipStrayFluxFraction: `float`, optional
    Minimum stray-flux portion.
    Any stray-flux portion less than ``clipStrayFluxFraction`` is
    clipped to zero.
getTemplateSum: `bool`, optional
    As part of the flux calculation, the sum of the templates is
    calculated. If ``getTemplateSum==True`` then the sum of the
    templates is stored in the result (a `DeblendedFootprint`).

Returns
-------
modified: `bool`
    Apportion flux always modifies the templates, so ``modified`` is
    always ``True``. However, this should likely be the final step and
    it is unlikely that any deblender plugins will be re-run.

Definition at line 1250 of file plugins.py.

                  getTemplateSum=False):
    """Apportion flux to all of the peak templates in each filter
 
    Divide the ``maskedImage`` flux amongst all of the templates based
    on the fraction of flux assigned to each ``template``.
    Leftover "stray flux" is assigned to peaks based on the other parameters.
 
    Parameters
    ----------
    debResult: `lsst.meas.deblender.baseline.DeblenderResult`
        Container for the final deblender results.
    log: `log.Log`
        LSST logger for logging purposes.
    assignStrayFlux: `bool`, optional
        If True then flux in the parent footprint that is not covered by any
        of the template footprints is assigned to templates based on
        their 1/(1+r^2) distance.
        How the flux is apportioned is determined by ``strayFluxAssignment``.
    strayFluxAssignment: `string`, optional
        Determines how stray flux is apportioned.
 
        * ``trim``: Trim stray flux and do not include in any footprints
        * ``r-to-peak`` (default): Stray flux is assigned based on
          (1/(1+r^2) from the peaks
        * ``r-to-footprint``: Stray flux is distributed to the footprints
          based on 1/(1+r^2) of the minimum distance from the stray flux
          to footprint
        * ``nearest-footprint``: Stray flux is assigned to the footprint
          with lowest L-1 (Manhattan) distance to the stray flux
 
    strayFluxToPointSources: `string`, optional
        Determines how stray flux is apportioned to point sources
 
        * ``never``: never apportion stray flux to point sources
        * ``necessary`` (default): point sources are included only if there
          are no extended sources nearby
        * ``always``: point sources are always included in
          the 1/(1+r^2) splitting
 
    clipStrayFluxFraction: `float`, optional
        Minimum stray-flux portion.
        Any stray-flux portion less than ``clipStrayFluxFraction`` is
        clipped to zero.
    getTemplateSum: `bool`, optional
        As part of the flux calculation, the sum of the templates is
        calculated. If ``getTemplateSum==True`` then the sum of the
        templates is stored in the result (a `DeblendedFootprint`).
 
    Returns
    -------
    modified: `bool`
        Apportion flux always modifies the templates, so ``modified`` is
        always ``True``. However, this should likely be the final step and
        it is unlikely that any deblender plugins will be re-run.
    """
    validStrayPtSrc = ['never', 'necessary', 'always']
    validStrayAssign = ['r-to-peak', 'r-to-footprint', 'nearest-footprint', 'trim']
    if strayFluxToPointSources not in validStrayPtSrc:
        raise ValueError((('strayFluxToPointSources: value \"%s\" not in the set of allowed values: ') %
                          strayFluxToPointSources) + str(validStrayPtSrc))
    if strayFluxAssignment not in validStrayAssign:
        raise ValueError((('strayFluxAssignment: value \"%s\" not in the set of allowed values: ') %
                          strayFluxAssignment) + str(validStrayAssign))
 
    for fidx in debResult.filters:
        dp = debResult.deblendedParents[fidx]
        # Prepare inputs to "apportionFlux" call.
        # template maskedImages
        tmimgs = []
        # template footprints
        tfoots = []
        # deblended as psf
        dpsf = []
        # peak x,y
        pkx = []
        pky = []
        # indices of valid templates
        ibi = []
        bb = dp.fp.getBBox()
 
        for peaki, pkres in enumerate(dp.peaks):
            if pkres.skip:
                continue
            tmimgs.append(pkres.templateImage)
            tfoots.append(pkres.templateFootprint)
            # for stray flux...
            dpsf.append(pkres.deblendedAsPsf)
            pk = pkres.peak
            pkx.append(pk.getIx())
            pky.append(pk.getIy())
            ibi.append(pkres.pki)
 
        # Now apportion flux according to the templates
        log.trace('Apportioning flux among %i templates', len(tmimgs))
        sumimg = afwImage.ImageF(bb)
        # .getDimensions())
        # sumimg.setXY0(bb.getMinX(), bb.getMinY())
 
        strayopts = 0
        if strayFluxAssignment == 'trim':
            assignStrayFlux = False
            strayopts |= bUtils.STRAYFLUX_TRIM
        if assignStrayFlux:
            strayopts |= bUtils.ASSIGN_STRAYFLUX
            if strayFluxToPointSources == 'necessary':
                strayopts |= bUtils.STRAYFLUX_TO_POINT_SOURCES_WHEN_NECESSARY
            elif strayFluxToPointSources == 'always':
                strayopts |= bUtils.STRAYFLUX_TO_POINT_SOURCES_ALWAYS
 
            if strayFluxAssignment == 'r-to-peak':
                # this is the default
                pass
            elif strayFluxAssignment == 'r-to-footprint':
                strayopts |= bUtils.STRAYFLUX_R_TO_FOOTPRINT
            elif strayFluxAssignment == 'nearest-footprint':
                strayopts |= bUtils.STRAYFLUX_NEAREST_FOOTPRINT
 
        portions, strayflux = bUtils.apportionFlux(dp.maskedImage, dp.fp, tmimgs, tfoots, sumimg, dpsf,
                                                   pkx, pky, strayopts, clipStrayFluxFraction)
 
        # Shrink parent to union of children
        if strayFluxAssignment == 'trim':
            finalSpanSet = afwGeom.SpanSet()
            for foot in tfoots:
                finalSpanSet = finalSpanSet.union(foot.spans)
            dp.fp.setSpans(finalSpanSet)
 
        # Store the template sum in the deblender result
        if getTemplateSum:
            debResult.setTemplateSums(sumimg, fidx)
 
        # Save the apportioned fluxes
        ii = 0
        for j, (pk, pkres) in enumerate(zip(dp.fp.getPeaks(), dp.peaks)):
            if pkres.skip:
                continue
            pkres.setFluxPortion(portions[ii])
 
            if assignStrayFlux:
                # NOTE that due to a swig bug (https://github.com/swig/swig/issues/59)
                # we CANNOT iterate over "strayflux", but must index into it.
                stray = strayflux[ii]
            else:
                stray = None
            ii += 1
 
            pkres.setStrayFlux(stray)
 
        # Set child footprints to contain the right number of peaks.
        for j, (pk, pkres) in enumerate(zip(dp.fp.getPeaks(), dp.peaks)):
            if pkres.skip:
                continue
 
            for foot, add in [(pkres.templateFootprint, True), (pkres.origFootprint, True),
                              (pkres.strayFlux, False)]:
                if foot is None:
                    continue
                pks = foot.getPeaks()
                pks.clear()
                if add:
                    pks.append(pk)
    return True

buildSymmetricTemplates()

def lsst.meas.deblender.plugins.buildSymmetricTemplates	(		debResult,
			log,
			patchEdges = False,
			setOrigTemplate = True
	)

Build a symmetric template for each peak in each filter

Given ``maskedImageF``, ``footprint``, and a ``DebldendedPeak``, creates
a symmetric template (``templateImage`` and ``templateFootprint``) around
the peak for all peaks not flagged as ``skip`` or ``deblendedAsPsf``.

Parameters
----------
debResult: `lsst.meas.deblender.baseline.DeblenderResult`
    Container for the final deblender results.
log: `log.Log`
    LSST logger for logging purposes.
patchEdges: `bool`, optional
    If True and if the parent Footprint touches pixels with the
    ``EDGE`` bit set, then grow the parent Footprint to include
    all symmetric templates.

Returns
-------
modified: `bool`
    If any peaks are not skipped or marked as point sources,
    ``modified`` is ``True. Otherwise ``modified`` is ``False``.

Definition at line 708 of file plugins.py.

def buildSymmetricTemplates(debResult, log, patchEdges=False, setOrigTemplate=True):
    """Build a symmetric template for each peak in each filter
 
    Given ``maskedImageF``, ``footprint``, and a ``DebldendedPeak``, creates
    a symmetric template (``templateImage`` and ``templateFootprint``) around
    the peak for all peaks not flagged as ``skip`` or ``deblendedAsPsf``.
 
    Parameters
    ----------
    debResult: `lsst.meas.deblender.baseline.DeblenderResult`
        Container for the final deblender results.
    log: `log.Log`
        LSST logger for logging purposes.
    patchEdges: `bool`, optional
        If True and if the parent Footprint touches pixels with the
        ``EDGE`` bit set, then grow the parent Footprint to include
        all symmetric templates.
 
    Returns
    -------
    modified: `bool`
        If any peaks are not skipped or marked as point sources,
        ``modified`` is ``True. Otherwise ``modified`` is ``False``.
    """
    modified = False
    # Create the Templates for each peak in each filter
    for fidx in debResult.filters:
        dp = debResult.deblendedParents[fidx]
        imbb = dp.img.getBBox()
        log.trace('Creating templates for footprint at x0,y0,W,H = %i, %i, %i, %i)', dp.x0, dp.y0, dp.W, dp.H)
 
        for peaki, pkres in enumerate(dp.peaks):
            log.trace('Deblending peak %i of %i', peaki, len(dp.peaks))
            # TODO: Check debResult to see if the peak is deblended as a point source
            # when comparing all bands, not just a single band
            if pkres.skip or pkres.deblendedAsPsf:
                continue
            modified = True
            pk = pkres.peak
            cx, cy = pk.getIx(), pk.getIy()
            if not imbb.contains(geom.Point2I(cx, cy)):
                log.trace('Peak center is not inside image; skipping %i', pkres.pki)
                pkres.setOutOfBounds()
                continue
            log.trace('computing template for peak %i at (%i, %i)', pkres.pki, cx, cy)
            timg, tfoot, patched = bUtils.buildSymmetricTemplate(dp.maskedImage, dp.fp, pk, dp.avgNoise,
                                                                 True, patchEdges)
            if timg is None:
                log.trace('Peak %i at (%i, %i): failed to build symmetric template', pkres.pki, cx, cy)
                pkres.setFailedSymmetricTemplate()
                continue
 
            if patched:
                pkres.setPatched()
 
            # possibly save the original symmetric template
            if setOrigTemplate:
                pkres.setOrigTemplate(timg, tfoot)
            pkres.setTemplate(timg, tfoot)
    return modified
 
 

clipFootprintsToNonzero()

def lsst.meas.deblender.plugins.clipFootprintsToNonzero	(		debResult,
			log
	)

Clip non-zero spans in the template footprints for every peak in each filter.

Peak ``Footprint``\ s are clipped to the region in the image containing
non-zero values by dropping spans that are completely zero and moving
endpoints to non-zero pixels (but does not split spans that have
internal zeros).

Parameters
----------
debResult: `lsst.meas.deblender.baseline.DeblenderResult`
    Container for the final deblender results.
log: `log.Log`
    LSST logger for logging purposes.

Returns
-------
modified: `bool`
    Whether or not any templates were modified.
    This will be ``True`` as long as there is at least one source that
    is not flagged as a PSF.

Definition at line 1041 of file plugins.py.

def clipFootprintsToNonzero(debResult, log):
    r"""Clip non-zero spans in the template footprints for every peak in each filter.
 
    Peak ``Footprint``\ s are clipped to the region in the image containing
    non-zero values by dropping spans that are completely zero and moving
    endpoints to non-zero pixels (but does not split spans that have
    internal zeros).
 
    Parameters
    ----------
    debResult: `lsst.meas.deblender.baseline.DeblenderResult`
        Container for the final deblender results.
    log: `log.Log`
        LSST logger for logging purposes.
 
    Returns
    -------
    modified: `bool`
        Whether or not any templates were modified.
        This will be ``True`` as long as there is at least one source that
        is not flagged as a PSF.
    """
    # Loop over all filters
    for fidx in debResult.filters:
        dp = debResult.deblendedParents[fidx]
        for peaki, pkres in enumerate(dp.peaks):
            if pkres.skip or pkres.deblendedAsPsf:
                continue
            timg, tfoot = pkres.templateImage, pkres.templateFootprint
            clipFootprintToNonzeroImpl(tfoot, timg)
            if not tfoot.getBBox().isEmpty() and tfoot.getBBox() != timg.getBBox(afwImage.PARENT):
                timg = timg.Factory(timg, tfoot.getBBox(), afwImage.PARENT, True)
            pkres.setTemplate(timg, tfoot)
    return False
 
 

clipFootprintToNonzeroImpl()

def lsst.meas.deblender.plugins.clipFootprintToNonzeroImpl	(		foot,
			image
	)

Clips the given *Footprint* to the region in the *Image*
containing non-zero values.

The clipping drops spans that are
totally zero, and moves endpoints to non-zero; it does not
split spans that have internal zeros.

Definition at line 38 of file plugins.py.

def clipFootprintToNonzeroImpl(foot, image):
    """Clips the given *Footprint* to the region in the *Image*
    containing non-zero values.
 
    The clipping drops spans that are
    totally zero, and moves endpoints to non-zero; it does not
    split spans that have internal zeros.
    """
    x0 = image.getX0()
    y0 = image.getY0()
    xImMax = x0 + image.getDimensions().getX()
    yImMax = y0 + image.getDimensions().getY()
    newSpans = []
    arr = image.getArray()
    for span in foot.spans:
        y = span.getY()
        if y < y0 or y > yImMax:
            continue
        spanX0 = span.getX0()
        spanX1 = span.getX1()
        xMin = spanX0 if spanX0 >= x0 else x0
        xMax = spanX1 if spanX1 <= xImMax else xImMax
        xarray = np.arange(xMin, xMax+1)[arr[y-y0, xMin-x0:xMax-x0+1] != 0]
        if len(xarray) > 0:
            newSpans.append(afwGeom.Span(y, xarray[0], xarray[-1]))
    # Time to update the SpanSet
    foot.setSpans(afwGeom.SpanSet(newSpans, normalize=False))
    foot.removeOrphanPeaks()
 
 

fitPsfs()

def lsst.meas.deblender.plugins.fitPsfs	(		debResult,
			log,
			psfChisqCut1 = 1.5,
			psfChisqCut2 = 1.5,
			psfChisqCut2b = 1.5,
			tinyFootprintSize = 2
	)

Fit a PSF + smooth background model (linear) to a small region
around each peak.

This function will iterate over all filters in deblender result but does
not compare results across filters.
DeblendedPeaks that pass the cuts have their templates modified to the
PSF + background model and their ``deblendedAsPsf`` property set
to ``True``.

This will likely be replaced in the future with a function that compares
the psf chi-squared cuts so that peaks flagged as point sources will be
considered point sources in all bands.

Parameters
----------
debResult: `lsst.meas.deblender.baseline.DeblenderResult`
    Container for the final deblender results.
log: `log.Log`
    LSST logger for logging purposes.
psfChisqCut*: `float`, optional
    ``psfChisqCut1`` is the maximum chi-squared-per-degree-of-freedom
    allowed for a peak to be considered a PSF match without recentering.
    A fit is also made that includes terms to recenter the PSF.
    ``psfChisqCut2`` is the same as ``psfChisqCut1`` except it
    determines the restriction on the fit that includes
    recentering terms.
    If the peak is a match for a re-centered PSF, the PSF is
    repositioned at the new center and
    the peak footprint is fit again, this time to the new PSF.
    If the resulting chi-squared-per-degree-of-freedom is less than
    ``psfChisqCut2b`` then it passes the re-centering algorithm.
    If the peak passes both the re-centered and fixed position cuts,
    the better of the two is accepted, but parameters for all three psf
    fits are stored in the ``DebldendedPeak``.
    The default for ``psfChisqCut1``, ``psfChisqCut2``, and
    ``psfChisqCut2b`` is ``1.5``.
tinyFootprintSize: `float`, optional
    The PSF model is shrunk to the size that contains the original
    footprint. If the bbox of the clipped PSF model for a peak is
    smaller than ``max(tinyFootprintSize,2)`` then ``tinyFootprint`` for
    the peak is set to ``True`` and the peak is not fit. The default is 2.

Returns
-------
modified: `bool`
    If any templates have been assigned to PSF point sources then
    ``modified`` is ``True``, otherwise it is ``False``.

Definition at line 164 of file plugins.py.

def fitPsfs(debResult, log, psfChisqCut1=1.5, psfChisqCut2=1.5, psfChisqCut2b=1.5, tinyFootprintSize=2):
    """Fit a PSF + smooth background model (linear) to a small region
    around each peak.
 
    This function will iterate over all filters in deblender result but does
    not compare results across filters.
    DeblendedPeaks that pass the cuts have their templates modified to the
    PSF + background model and their ``deblendedAsPsf`` property set
    to ``True``.
 
    This will likely be replaced in the future with a function that compares
    the psf chi-squared cuts so that peaks flagged as point sources will be
    considered point sources in all bands.
 
    Parameters
    ----------
    debResult: `lsst.meas.deblender.baseline.DeblenderResult`
        Container for the final deblender results.
    log: `log.Log`
        LSST logger for logging purposes.
    psfChisqCut*: `float`, optional
        ``psfChisqCut1`` is the maximum chi-squared-per-degree-of-freedom
        allowed for a peak to be considered a PSF match without recentering.
        A fit is also made that includes terms to recenter the PSF.
        ``psfChisqCut2`` is the same as ``psfChisqCut1`` except it
        determines the restriction on the fit that includes
        recentering terms.
        If the peak is a match for a re-centered PSF, the PSF is
        repositioned at the new center and
        the peak footprint is fit again, this time to the new PSF.
        If the resulting chi-squared-per-degree-of-freedom is less than
        ``psfChisqCut2b`` then it passes the re-centering algorithm.
        If the peak passes both the re-centered and fixed position cuts,
        the better of the two is accepted, but parameters for all three psf
        fits are stored in the ``DebldendedPeak``.
        The default for ``psfChisqCut1``, ``psfChisqCut2``, and
        ``psfChisqCut2b`` is ``1.5``.
    tinyFootprintSize: `float`, optional
        The PSF model is shrunk to the size that contains the original
        footprint. If the bbox of the clipped PSF model for a peak is
        smaller than ``max(tinyFootprintSize,2)`` then ``tinyFootprint`` for
        the peak is set to ``True`` and the peak is not fit. The default is 2.
 
    Returns
    -------
    modified: `bool`
        If any templates have been assigned to PSF point sources then
        ``modified`` is ``True``, otherwise it is ``False``.
    """
    from .baseline import CachingPsf
    modified = False
    # Loop over all of the filters to build the PSF
    for fidx in debResult.filters:
        dp = debResult.deblendedParents[fidx]
        peaks = dp.fp.getPeaks()
        cpsf = CachingPsf(dp.psf)
 
        # create mask image for pixels within the footprint
        fmask = afwImage.Mask(dp.bb)
        fmask.setXY0(dp.bb.getMinX(), dp.bb.getMinY())
        dp.fp.spans.setMask(fmask, 1)
 
        # pk.getF() -- retrieving the floating-point location of the peak
        # -- actually shows up in the profile if we do it in the loop, so
        # grab them all here.
        peakF = [pk.getF() for pk in peaks]
 
        for pki, (pk, pkres, pkF) in enumerate(zip(peaks, dp.peaks, peakF)):
            log.trace('Filter %s, Peak %i', fidx, pki)
            ispsf = _fitPsf(dp.fp, fmask, pk, pkF, pkres, dp.bb, peaks, peakF, log, cpsf, dp.psffwhm,
                            dp.img, dp.varimg, psfChisqCut1, psfChisqCut2, psfChisqCut2b, tinyFootprintSize)
            modified = modified or ispsf
    return modified
 
 

makeTemplatesMonotonic()

def lsst.meas.deblender.plugins.makeTemplatesMonotonic	(		debResult,
			log
	)

Make the templates monotonic.

The pixels in the templates are modified such that pixels further
from the peak will have values smaller than those closer to the peak.

Parameters
----------
debResult: `lsst.meas.deblender.baseline.DeblenderResult`
    Container for the final deblender results.
log: `log.Log`
    LSST logger for logging purposes.

Returns
-------
modified: `bool`
    Whether or not any templates were modified.
    This will be ``True`` as long as there is at least one source that
    is not flagged as a PSF.

Definition at line 1005 of file plugins.py.

def makeTemplatesMonotonic(debResult, log):
    """Make the templates monotonic.
 
    The pixels in the templates are modified such that pixels further
    from the peak will have values smaller than those closer to the peak.
 
    Parameters
    ----------
    debResult: `lsst.meas.deblender.baseline.DeblenderResult`
        Container for the final deblender results.
    log: `log.Log`
        LSST logger for logging purposes.
 
    Returns
    -------
    modified: `bool`
        Whether or not any templates were modified.
        This will be ``True`` as long as there is at least one source that
        is not flagged as a PSF.
    """
    modified = False
    # Loop over all filters
    for fidx in debResult.filters:
        dp = debResult.deblendedParents[fidx]
        for peaki, pkres in enumerate(dp.peaks):
            if pkres.skip or pkres.deblendedAsPsf:
                continue
            modified = True
            timg, tfoot = pkres.templateImage, pkres.templateFootprint
            pk = pkres.peak
            log.trace('Making template %i monotonic', pkres.pki)
            bUtils.makeMonotonic(timg, pk)
            pkres.setTemplate(timg, tfoot)
    return modified
 
 

medianSmoothTemplates()

def lsst.meas.deblender.plugins.medianSmoothTemplates	(		debResult,
			log,
			medianFilterHalfsize = 2
	)

Applying median smoothing filter to the template images for every
peak in every filter.

Parameters
----------
debResult: `lsst.meas.deblender.baseline.DeblenderResult`
    Container for the final deblender results.
log: `log.Log`
    LSST logger for logging purposes.
medianFilterHalfSize: `int`, optional
    Half the box size of the median filter, i.e. a
    ``medianFilterHalfSize`` of 50 means that each output pixel will
    be the median of  the pixels in a 101 x 101-pixel box in the input
    image. This parameter is only used when
    ``medianSmoothTemplate==True``, otherwise it is ignored.

Returns
-------
modified: `bool`
    Whether or not any templates were modified.
    This will be ``True`` as long as there is at least one source that
    is not flagged as a PSF.

Definition at line 956 of file plugins.py.

def medianSmoothTemplates(debResult, log, medianFilterHalfsize=2):
    """Applying median smoothing filter to the template images for every
    peak in every filter.
 
    Parameters
    ----------
    debResult: `lsst.meas.deblender.baseline.DeblenderResult`
        Container for the final deblender results.
    log: `log.Log`
        LSST logger for logging purposes.
    medianFilterHalfSize: `int`, optional
        Half the box size of the median filter, i.e. a
        ``medianFilterHalfSize`` of 50 means that each output pixel will
        be the median of  the pixels in a 101 x 101-pixel box in the input
        image. This parameter is only used when
        ``medianSmoothTemplate==True``, otherwise it is ignored.
 
    Returns
    -------
    modified: `bool`
        Whether or not any templates were modified.
        This will be ``True`` as long as there is at least one source that
        is not flagged as a PSF.
    """
    modified = False
    # Loop over all filters
    for fidx in debResult.filters:
        dp = debResult.deblendedParents[fidx]
        for peaki, pkres in enumerate(dp.peaks):
            if pkres.skip or pkres.deblendedAsPsf:
                continue
            modified = True
            timg, tfoot = pkres.templateImage, pkres.templateFootprint
            filtsize = medianFilterHalfsize*2 + 1
            if timg.getWidth() >= filtsize and timg.getHeight() >= filtsize:
                log.trace('Median filtering template %i', pkres.pki)
                # We want the output to go in "t1", so copy it into
                # "inimg" for input
                inimg = timg.Factory(timg, True)
                bUtils.medianFilter(inimg, timg, medianFilterHalfsize)
                # possible save this median-filtered template
                pkres.setMedianFilteredTemplate(timg, tfoot)
            else:
                log.trace('Not median-filtering template %i: size %i x %i smaller than required %i x %i',
                          pkres.pki, timg.getWidth(), timg.getHeight(), filtsize, filtsize)
            pkres.setTemplate(timg, tfoot)
    return modified
 
 

rampFluxAtEdge()

def lsst.meas.deblender.plugins.rampFluxAtEdge	(		debResult,
			log,
			patchEdges = False
	)

Adjust flux on the edges of the template footprints.

Using the PSF, a peak ``~afw.detection.Footprint`` with pixels on the edge
of ``footprint`` is grown by the ``psffwhm*1.5`` and filled in
with ramped pixels. The result is a new symmetric footprint
template for the peaks near the edge.

Parameters
----------
debResult: `lsst.meas.deblender.baseline.DeblenderResult`
    Container for the final deblender results.
log: `log.Log`
    LSST logger for logging purposes.
patchEdges: `bool`, optional
    If True and if the parent Footprint touches pixels with the
    ``EDGE`` bit set, then grow the parent Footprint to include
    all symmetric templates.

Returns
-------
modified: `bool`
    If any peaks have their templates modified to include flux at the
    edges, ``modified`` is ``True``.

Definition at line 770 of file plugins.py.

def rampFluxAtEdge(debResult, log, patchEdges=False):
    r"""Adjust flux on the edges of the template footprints.
 
    Using the PSF, a peak ``~afw.detection.Footprint`` with pixels on the edge
    of ``footprint`` is grown by the ``psffwhm*1.5`` and filled in
    with ramped pixels. The result is a new symmetric footprint
    template for the peaks near the edge.
 
    Parameters
    ----------
    debResult: `lsst.meas.deblender.baseline.DeblenderResult`
        Container for the final deblender results.
    log: `log.Log`
        LSST logger for logging purposes.
    patchEdges: `bool`, optional
        If True and if the parent Footprint touches pixels with the
        ``EDGE`` bit set, then grow the parent Footprint to include
        all symmetric templates.
 
    Returns
    -------
    modified: `bool`
        If any peaks have their templates modified to include flux at the
        edges, ``modified`` is ``True``.
    """
    modified = False
    # Loop over all filters
    for fidx in debResult.filters:
        dp = debResult.deblendedParents[fidx]
        log.trace('Checking for significant flux at edge: sigma1=%g', dp.avgNoise)
 
        for peaki, pkres in enumerate(dp.peaks):
            if pkres.skip or pkres.deblendedAsPsf:
                continue
            timg, tfoot = pkres.templateImage, pkres.templateFootprint
            if bUtils.hasSignificantFluxAtEdge(timg, tfoot, 3*dp.avgNoise):
                log.trace("Template %i has significant flux at edge: ramping", pkres.pki)
                try:
                    (timg2, tfoot2, patched) = _handle_flux_at_edge(log, dp.psffwhm, timg, tfoot, dp.fp,
                                                                    dp.maskedImage, dp.x0, dp.x1,
                                                                    dp.y0, dp.y1, dp.psf, pkres.peak,
                                                                    dp.avgNoise, patchEdges)
                except lsst.pex.exceptions.Exception as exc:
                    if (isinstance(exc, lsst.pex.exceptions.InvalidParameterError)
                            and "CoaddPsf" in str(exc)):
                        pkres.setOutOfBounds()
                        continue
                    raise
                pkres.setRampedTemplate(timg2, tfoot2)
                if patched:
                    pkres.setPatched()
                pkres.setTemplate(timg2, tfoot2)
                modified = True
    return modified
 
 

reconstructTemplates()

def lsst.meas.deblender.plugins.reconstructTemplates	(		debResult,
			log,
			maxTempDotProd = 0.5
	)

Remove "degenerate templates"

If galaxies have substructure, such as face-on spirals, the process of
identifying peaks can "shred" the galaxy into many pieces. The templates
of shredded galaxies are typically quite similar because they represent
the same galaxy, so we try to identify these "degenerate" peaks
by looking at the inner product (in pixel space) of pairs of templates.
If they are nearly parallel, we only keep one of the peaks and reject
the other. If only one of the peaks is a PSF template, the other template
is used, otherwise the one with the maximum template value is kept.

Parameters
----------
debResult: `lsst.meas.deblender.baseline.DeblenderResult`
    Container for the final deblender results.
log: `log.Log`
    LSST logger for logging purposes.
maxTempDotProd: `float`, optional
    All dot products between templates greater than ``maxTempDotProd``
    will result in one of the templates removed.

Returns
-------
modified: `bool`
    If any degenerate templates are found, ``modified`` is ``True``.

Definition at line 1149 of file plugins.py.

def reconstructTemplates(debResult, log, maxTempDotProd=0.5):
    """Remove "degenerate templates"
 
    If galaxies have substructure, such as face-on spirals, the process of
    identifying peaks can "shred" the galaxy into many pieces. The templates
    of shredded galaxies are typically quite similar because they represent
    the same galaxy, so we try to identify these "degenerate" peaks
    by looking at the inner product (in pixel space) of pairs of templates.
    If they are nearly parallel, we only keep one of the peaks and reject
    the other. If only one of the peaks is a PSF template, the other template
    is used, otherwise the one with the maximum template value is kept.
 
    Parameters
    ----------
    debResult: `lsst.meas.deblender.baseline.DeblenderResult`
        Container for the final deblender results.
    log: `log.Log`
        LSST logger for logging purposes.
    maxTempDotProd: `float`, optional
        All dot products between templates greater than ``maxTempDotProd``
        will result in one of the templates removed.
 
    Returns
    -------
    modified: `bool`
        If any degenerate templates are found, ``modified`` is ``True``.
    """
    log.trace('Looking for degnerate templates')
 
    foundReject = False
    for fidx in debResult.filters:
        dp = debResult.deblendedParents[fidx]
        nchild = np.sum([pkres.skip is False for pkres in dp.peaks])
        indexes = [pkres.pki for pkres in dp.peaks if pkres.skip is False]
 
        # We build a matrix that stores the dot product between templates.
        # We convert the template images to HeavyFootprints because they already have a method
        # to compute the dot product.
        A = np.zeros((nchild, nchild))
        maxTemplate = []
        heavies = []
        for pkres in dp.peaks:
            if pkres.skip:
                continue
            heavies.append(afwDet.makeHeavyFootprint(pkres.templateFootprint,
                                                     afwImage.MaskedImageF(pkres.templateImage)))
            maxTemplate.append(np.max(pkres.templateImage.getArray()))
 
        for i in range(nchild):
            for j in range(i + 1):
                A[i, j] = heavies[i].dot(heavies[j])
 
        # Normalize the dot products to get the cosine of the angle between templates
        for i in range(nchild):
            for j in range(i):
                norm = A[i, i]*A[j, j]
                if norm <= 0:
                    A[i, j] = 0
                else:
                    A[i, j] /= np.sqrt(norm)
 
        # Iterate over pairs of objects and find the maximum non-diagonal element of the matrix.
        # Exit the loop once we find a single degenerate pair greater than the threshold.
        rejectedIndex = -1
        for i in range(nchild):
            currentMax = 0.
            for j in range(i):
                if A[i, j] > currentMax:
                    currentMax = A[i, j]
                    if currentMax > maxTempDotProd:
                        foundReject = True
                        rejectedIndex = j
 
            if foundReject:
                break
 
        del A
 
        # If one of the objects is identified as a PSF keep the other one, otherwise keep the one
        # with the maximum template value
        if foundReject:
            keep = indexes[i]
            reject = indexes[rejectedIndex]
            if dp.peaks[keep].deblendedAsPsf and dp.peaks[reject].deblendedAsPsf is False:
                keep = indexes[rejectedIndex]
                reject = indexes[i]
            elif dp.peaks[keep].deblendedAsPsf is False and dp.peaks[reject].deblendedAsPsf:
                reject = indexes[rejectedIndex]
                keep = indexes[i]
            else:
                if maxTemplate[rejectedIndex] > maxTemplate[i]:
                    keep = indexes[rejectedIndex]
                    reject = indexes[i]
            log.trace('Removing object with index %d : %f.  Degenerate with %d',
                      reject, currentMax, keep)
            dp.peaks[reject].skip = True
            dp.peaks[reject].degenerate = True
 
    return foundReject
 
 

weightTemplates()

def lsst.meas.deblender.plugins.weightTemplates	(		debResult,
			log
	)

Weight the templates to best fit the observed image in each filter

This function re-weights the templates so that their linear combination
best represents the observed image in that filter.
In the future it may be useful to simultaneously weight all of the
filters together.

Parameters
----------
debResult: `lsst.meas.deblender.baseline.DeblenderResult`
    Container for the final deblender results.
log: `log.Log`
    LSST logger for logging purposes.

Returns
-------
modified: `bool`
    ``weightTemplates`` does not actually modify the ``Footprint``
    templates other than to add a weight to them, so ``modified``
    is always ``False``.

Definition at line 1077 of file plugins.py.

def weightTemplates(debResult, log):
    """Weight the templates to best fit the observed image in each filter
 
    This function re-weights the templates so that their linear combination
    best represents the observed image in that filter.
    In the future it may be useful to simultaneously weight all of the
    filters together.
 
    Parameters
    ----------
    debResult: `lsst.meas.deblender.baseline.DeblenderResult`
        Container for the final deblender results.
    log: `log.Log`
        LSST logger for logging purposes.
 
    Returns
    -------
    modified: `bool`
        ``weightTemplates`` does not actually modify the ``Footprint``
        templates other than to add a weight to them, so ``modified``
        is always ``False``.
    """
    # Weight the templates by doing a least-squares fit to the image
    log.trace('Weighting templates')
    for fidx in debResult.filters:
        _weightTemplates(debResult.deblendedParents[fidx])
    return False