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#
# LSST Data Management System
# Copyright 2008-2013 LSST Corporation.
#
# This product includes software developed by the
# LSST Project (http://www.lsst.org/).
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the LSST License Statement and
# the GNU General Public License along with this program. If not,
# see <http://www.lsstcorp.org/LegalNotices/>.
#
"""
This module contains a Task to register (align) multiple images.
"""
__all__ = ["RegisterTask", "RegisterConfig"]
import math
import numpy
from lsst.pex.config import Config, Field, ConfigField
from lsst.pipe.base import Task, Struct
from lsst.meas.astrom.sip import makeCreateWcsWithSip
from lsst.afw.math import Warper
import lsst.afw.geom as afwGeom
import lsst.afw.table as afwTable
class RegisterConfig(Config):
"""Configuration for RegisterTask"""
matchRadius = Field(dtype=float, default=1.0, doc="Matching radius (arcsec)", check=lambda x: x > 0)
sipOrder = Field(dtype=int, default=4, doc="Order for SIP WCS", check=lambda x: x > 1)
sipIter = Field(dtype=int, default=3, doc="Rejection iterations for SIP WCS", check=lambda x: x > 0)
sipRej = Field(dtype=float, default=3.0, doc="Rejection threshold for SIP WCS", check=lambda x: x > 0)
warper = ConfigField(dtype=Warper.ConfigClass, doc="Configuration for warping")
class RegisterTask(Task):
"""
Task to register (align) multiple images.
The 'run' method provides a revised Wcs from matches and fitting sources.
Additional methods are provided as a convenience to warp an exposure
('warpExposure') and sources ('warpSources') with the new Wcs.
"""
ConfigClass = RegisterConfig
def run(self, inputSources, inputWcs, inputBBox, templateSources):
"""Register (align) an input exposure to the template
The sources must have RA,Dec set, and accurate to within the
'matchRadius' of the configuration in order to facilitate source
matching. We fit a new Wcs, but do NOT set it in the input exposure.
@param inputSources: Sources from input exposure
@param inputWcs: Wcs of input exposure
@param inputBBox: Bounding box of input exposure
@param templateSources: Sources from template exposure
@return Struct(matches: Matches between sources,
wcs: Wcs for input in frame of template,
)
"""
matches = self.matchSources(inputSources, templateSources)
wcs = self.fitWcs(matches, inputWcs, inputBBox)
return Struct(matches=matches, wcs=wcs)
def matchSources(self, inputSources, templateSources):
"""Match sources between the input and template
The order of the input arguments matters (because the later Wcs
fitting assumes a particular order).
@param inputSources: Source catalog of the input frame
@param templateSources: Source of the target frame
@return Match list
"""
matches = afwTable.matchRaDec(templateSources, inputSources,
self.config.matchRadius*afwGeom.arcseconds)
self.log.info("Matching within %.1f arcsec: %d matches" % (self.config.matchRadius, len(matches)))
self.metadata.set("MATCH_NUM", len(matches))
92 ↛ 93line 92 didn't jump to line 93, because the condition on line 92 was never true if len(matches) == 0:
raise RuntimeError("Unable to match source catalogs")
return matches
def fitWcs(self, matches, inputWcs, inputBBox):
"""Fit Wcs to matches
The fitting includes iterative sigma-clipping.
@param matches: List of matches (first is target, second is input)
@param inputWcs: Original input Wcs
@param inputBBox: Bounding box of input image
@return Wcs
"""
copyMatches = type(matches)(matches)
refCoordKey = copyMatches[0].first.getTable().getCoordKey()
inCentroidKey = copyMatches[0].second.getTable().getCentroidKey()
109 ↛ 128line 109 didn't jump to line 128, because the loop on line 109 didn't complete for i in range(self.config.sipIter):
sipFit = makeCreateWcsWithSip(copyMatches, inputWcs, self.config.sipOrder, inputBBox)
self.log.debug("Registration WCS RMS iteration %d: %f pixels",
i, sipFit.getScatterInPixels())
wcs = sipFit.getNewWcs()
dr = [m.first.get(refCoordKey).separation(
wcs.pixelToSky(m.second.get(inCentroidKey))).asArcseconds() for
m in copyMatches]
dr = numpy.array(dr)
rms = math.sqrt((dr*dr).mean()) # RMS from zero
rms = max(rms, 1.0e-9) # Don't believe any RMS smaller than this
self.log.debug("Registration iteration %d: rms=%f", i, rms)
good = numpy.where(dr < self.config.sipRej*rms)[0]
numBad = len(copyMatches) - len(good)
self.log.debug("Registration iteration %d: rejected %d", i, numBad)
if numBad == 0:
break
copyMatches = type(matches)(copyMatches[i] for i in good)
sipFit = makeCreateWcsWithSip(copyMatches, inputWcs, self.config.sipOrder, inputBBox)
self.log.info("Registration WCS: final WCS RMS=%f pixels from %d matches" %
(sipFit.getScatterInPixels(), len(copyMatches)))
self.metadata.set("SIP_RMS", sipFit.getScatterInPixels())
self.metadata.set("SIP_GOOD", len(copyMatches))
self.metadata.set("SIP_REJECTED", len(matches) - len(copyMatches))
wcs = sipFit.getNewWcs()
return wcs
def warpExposure(self, inputExp, newWcs, templateWcs, templateBBox):
"""Warp input exposure to template frame
There are a variety of data attached to the exposure (e.g., PSF, Calib
and other metadata), but we do not attempt to warp these to the template
frame.
@param inputExp: Input exposure, to be warped
@param newWcs: Revised Wcs for input exposure
@param templateWcs: Target Wcs
@param templateBBox: Target bounding box
@return Warped exposure
"""
warper = Warper.fromConfig(self.config.warper)
copyExp = inputExp.Factory(inputExp.getMaskedImage(), newWcs)
alignedExp = warper.warpExposure(templateWcs, copyExp, destBBox=templateBBox)
return alignedExp
def warpSources(self, inputSources, newWcs, templateWcs, templateBBox):
"""Warp sources to the new frame
It would be difficult to transform all possible quantities of potential
interest between the two frames. We therefore update only the sky and
pixel coordinates.
@param inputSources: Sources on input exposure, to be warped
@param newWcs: Revised Wcs for input exposure
@param templateWcs: Target Wcs
@param templateBBox: Target bounding box
@return Warped sources
"""
alignedSources = inputSources.copy(True)
169 ↛ 172line 169 didn't jump to line 172, because the condition on line 169 was never false if not isinstance(templateBBox, afwGeom.Box2D):
# There is no method Box2I::contains(Point2D)
templateBBox = afwGeom.Box2D(templateBBox)
table = alignedSources.getTable()
coordKey = table.getCoordKey()
centroidKey = table.getCentroidKey()
deleteList = []
for i, s in enumerate(alignedSources):
oldCentroid = s.get(centroidKey)
newCoord = newWcs.pixelToSky(oldCentroid)
newCentroid = templateWcs.skyToPixel(newCoord)
180 ↛ 181line 180 didn't jump to line 181, because the condition on line 180 was never true if not templateBBox.contains(newCentroid):
deleteList.append(i)
continue
s.set(coordKey, newCoord)
s.set(centroidKey, newCentroid)
186 ↛ 187line 186 didn't jump to line 187, because the loop on line 186 never started for i in reversed(deleteList): # Delete from back so we don't change indices
del alignedSources[i]
return alignedSources
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