def getTanSipWcs(self, order=3, skyToleranceArcSec=0.001, pixelTolerance=0.01):
"""
Take an afw Detector and approximate its pixel-to-(Ra,Dec) transformation
with a TAN-SIP WCs.
Definition of the TAN-SIP WCS can be found in Shupe and Hook (2008)
http://fits.gsfc.nasa.gov/registry/sip/SIP_distortion_v1_0.pdf
@param order The order of the SIP polynomials to be fit to the
optical distortions [default: 3]
@param skyToleranceArcSec The maximum allowed error in the fitted world coordinates (in
arcseconds). [default: 0.001]
@param pixelTolerance The maximum allowed error in the fitted pixel coordinates.
[default: 0.02]
@returns tanSipWcs, an instantiation of lsst.afw.image's TanWcs class representing the WCS
of the detector with optical distortions parametrized by the SIP polynomials.
"""
bbox = self._detector.getBBox()
tanWcs = self.getTanWcs()
mockExposure = afwImage.ExposureF(bbox.getMaxX(), bbox.getMaxY())
mockExposure.setWcs(tanWcs)
mockExposure.setDetector(self._detector)
distortedWcs = afwImageUtils.getDistortedWcs(mockExposure.getInfo())
tanSipWcs = measAstrom.approximateWcs(
distortedWcs, bbox, order=order,
skyTolerance=skyToleranceArcSec*afwGeom.arcseconds,
pixelTolerance=pixelTolerance)
return tanSipWcs
def tanSipWcsFromDetector(detector_name,
camera_wrapper,
obs_metadata,
epoch,
order=3,
skyToleranceArcSec=0.001,
pixelTolerance=0.01):
"""
Take an afw Detector and approximate its pixel-to-(Ra,Dec) transformation
with a TAN-SIP WCs.
Definition of the TAN-SIP WCS can be found in Shupe and Hook (2008)
http://fits.gsfc.nasa.gov/registry/sip/SIP_distortion_v1_0.pdf
@param [in] detector_name is the name of the detector as stored
by afw
@param [in] camera_wrapper is an instantionat of a GalSimCameraWrapper
@param [in] obs_metadata is an instantiation of ObservationMetaData
characterizing the telescope's current pointing
@param [in] epoch is the epoch in Julian years of the equinox against
which RA and Dec are measured
@param [in] order is the order of the SIP polynomials to be fit to the
optical distortions (default 3)
@param [in] skyToleranceArcSec is the maximum allowed error in the fitted
world coordinates (in arcseconds). Default 0.001
@param [in] pixelTolerance is the maximum allowed error in the fitted
pixel coordinates. Default 0.02
@param [out] tanSipWcs is an instantiation of afw.image's TanWcs class
representing the WCS of the detector with optical distortions parametrized
by the SIP polynomials.
"""
bbox = camera_wrapper.getBBox(detector_name)
tanWcs = tanWcsFromDetector(detector_name, camera_wrapper, obs_metadata,
epoch)
mockExposure = afwImage.ExposureF(bbox.getMaxX(), bbox.getMaxY())
mockExposure.setWcs(tanWcs)
mockExposure.setDetector(camera_wrapper.camera[detector_name])
distortedWcs = afwImageUtils.getDistortedWcs(mockExposure.getInfo())
tanSipWcs = approximateWcs(distortedWcs,
order=order,
skyTolerance=skyToleranceArcSec *
afwGeom.arcseconds,
pixelTolerance=pixelTolerance,
detector_name=detector_name,
camera_wrapper=camera_wrapper,
obs_metadata=obs_metadata)
return tanSipWcs
def tanSipWcsFromDetector(afwDetector, afwCamera, obs_metadata, epoch,
order=3,
skyToleranceArcSec=0.001,
pixelTolerance=0.01):
"""
Take an afw Detector and approximate its pixel-to-(Ra,Dec) transformation
with a TAN-SIP WCs.
Definition of the TAN-SIP WCS can be found in Shupe and Hook (2008)
http://fits.gsfc.nasa.gov/registry/sip/SIP_distortion_v1_0.pdf
@param [in] afwDetector is an instantiation of afw.cameraGeom's Detector
class which characterizes the detector for which you wish to return th
WCS
@param [in] afwCamera is an instantiation of afw.cameraGeom's Camera
class which characterizes the camera containing afwDetector
@param [in] obs_metadata is an instantiation of ObservationMetaData
characterizing the telescope's current pointing
@param [in] epoch is the epoch in Julian years of the equinox against
which RA and Dec are measured
@param [in] order is the order of the SIP polynomials to be fit to the
optical distortions (default 3)
@param [in] skyToleranceArcSec is the maximum allowed error in the fitted
world coordinates (in arcseconds). Default 0.001
@param [in] pixelTolerance is the maximum allowed error in the fitted
pixel coordinates. Default 0.02
@param [out] tanSipWcs is an instantiation of afw.image's TanWcs class
representing the WCS of the detector with optical distortions parametrized
by the SIP polynomials.
"""
bbox = afwDetector.getBBox()
tanWcs = tanWcsFromDetector(afwDetector, afwCamera, obs_metadata, epoch)
mockExposure = afwImage.ExposureF(bbox.getMaxX(), bbox.getMaxY())
mockExposure.setWcs(tanWcs)
mockExposure.setDetector(afwDetector)
distortedWcs = afwImageUtils.getDistortedWcs(mockExposure.getInfo())
tanSipWcs = approximateWcs(distortedWcs, bbox,
order=order,
skyTolerance=skyToleranceArcSec*afwGeom.arcseconds,
pixelTolerance=pixelTolerance,
detector=afwDetector,
camera=afwCamera,
obs_metadata=obs_metadata)
return tanSipWcs
def createMatchMetadata(exposure, border=0):
"""Create metadata required for unpersisting a match list
@param[in] exposure exposure for which to create metadata
@param[in] border number of pixels by which to grow the bbox in all directions
@return metadata about the field (a daf_base PropertyList)
"""
bboxd = Box2D(exposure.getBBox())
bboxd.grow(border)
wcs = getDistortedWcs(exposure.getInfo())
ctrCoord = wcs.pixelToSky(bboxd.getCenter()).toIcrs()
approxRadius = max(
ctrCoord.angularSeparation(wcs.pixelToSky(pp).toIcrs())
for pp in bboxd.getCorners())
return MatchMetadata(ctrCoord, approxRadius,
exposure.getFilter().getName())
def _getExposureMetadata(self, exposure):
"""!Extract metadata from an exposure
@return an lsst.pipe.base.Struct containing the following exposure metadata:
- bbox: parent bounding box
- wcs: WCS (an lsst.afw.image.Wcs)
- calib calibration (an lsst.afw.image.Calib), or None if unknown
- filterName: name of filter, or None if unknown
"""
exposureInfo = exposure.getInfo()
filterName = exposureInfo.getFilter().getName() or None
if filterName == "_unknown_":
filterName = None
return pipeBase.Struct(
bbox=exposure.getBBox(),
wcs=getDistortedWcs(exposureInfo, log=self.log),
calib=exposureInfo.getCalib() if exposureInfo.hasCalib() else None,
filterName=filterName,
)
def getTanSipWcs(self,
order=3,
skyToleranceArcSec=0.001,
pixelTolerance=0.01):
"""
Take an afw Detector and approximate its pixel-to-(Ra,Dec) transformation
with a TAN-SIP WCs.
Definition of the TAN-SIP WCS can be found in Shupe and Hook (2008)
http://fits.gsfc.nasa.gov/registry/sip/SIP_distortion_v1_0.pdf
@param order The order of the SIP polynomials to be fit to the
optical distortions [default: 3]
@param skyToleranceArcSec The maximum allowed error in the fitted world coordinates (in
arcseconds). [default: 0.001]
@param pixelTolerance The maximum allowed error in the fitted pixel coordinates.
[default: 0.02]
@returns tanSipWcs, an instantiation of lsst.afw.image's TanWcs class representing the WCS
of the detector with optical distortions parametrized by the SIP polynomials.
"""
bbox = self._detector.getBBox()
tanWcs = self.getTanWcs()
mockExposure = afwImage.ExposureF(bbox.getMaxX(), bbox.getMaxY())
mockExposure.setWcs(tanWcs)
mockExposure.setDetector(self._detector)
distortedWcs = afwImageUtils.getDistortedWcs(mockExposure.getInfo())
tanSipWcs = measAstrom.approximateWcs(distortedWcs,
bbox,
order=order,
skyTolerance=skyToleranceArcSec *
afwGeom.arcseconds,
pixelTolerance=pixelTolerance)
return tanSipWcs
def createMatchMetadata(exposure):
"""Create metadata required for unpersisting a match list
@param[in] exposure exposure for which to create metadata
@return metadata about the field (a daf_base PropertyList)
"""
matchMeta = PropertyList()
bboxd = Box2D(exposure.getBBox())
ctrPos = bboxd.getCenter()
wcs = getDistortedWcs(exposure.getInfo())
ctrCoord = wcs.pixelToSky(ctrPos).toIcrs()
llCoord = wcs.pixelToSky(bboxd.getMin())
approxRadius = ctrCoord.angularSeparation(llCoord)
matchMeta.add('RA', ctrCoord.getRa().asDegrees(), 'field center in degrees')
matchMeta.add('DEC', ctrCoord.getDec().asDegrees(), 'field center in degrees')
matchMeta.add('RADIUS', approxRadius.asDegrees(), 'field radius in degrees, approximate')
matchMeta.add('SMATCHV', 1, 'SourceMatchVector version number')
filterName = exposure.getFilter().getName() or None
if filterName is not None and filterName not in ("_unknmown_", ""):
matchMeta.add('FILTER', filterName, 'filter name for tagalong data')
return matchMeta
def testGetDistortedWcs(self):
"""Test utils.getDistortedWcs
"""
dw = DetectorWrapper()
detector = dw.detector
# the standard case: the exposure's WCS is pure TAN WCS and distortion information is available;
# return a DistortedTanWcs
exposure = afwImage.ExposureF(10, 10)
exposure.setDetector(detector)
exposure.setWcs(self.tanWcs)
self.assertFalse(self.tanWcs.hasDistortion())
outWcs = getDistortedWcs(exposure.getInfo())
self.assertTrue(outWcs.hasDistortion())
self.assertIsInstance(outWcs, afwImage.DistortedTanWcs)
del exposure # avoid accidental reuse
del outWcs
# return the original WCS if the exposure's WCS has distortion
pixelsToTanPixels = afwGeom.RadialXYTransform([0, 1.001, 0.00003])
distortedWcs = afwImage.DistortedTanWcs(self.tanWcs, pixelsToTanPixels)
self.assertTrue(distortedWcs.hasDistortion())
exposure = afwImage.ExposureF(10, 10)
exposure.setWcs(distortedWcs)
exposure.setDetector(detector)
outWcs = getDistortedWcs(exposure.getInfo())
self.assertTrue(outWcs.hasDistortion())
self.assertIsInstance(outWcs, afwImage.DistortedTanWcs)
del exposure
del distortedWcs
del outWcs
# raise an exception if exposure has no WCS
exposure = afwImage.ExposureF(10, 10)
exposure.setDetector(detector)
with self.assertRaises(Exception):
getDistortedWcs(exposure.getInfo())
del exposure
# return the original pure TAN WCS if the exposure has no detector
exposure = afwImage.ExposureF(10, 10)
exposure.setWcs(self.tanWcs)
outWcs = getDistortedWcs(exposure.getInfo())
self.assertFalse(outWcs.hasDistortion())
self.assertIsInstance(outWcs, afwImage.TanWcs)
self.assertNotIsInstance(outWcs, afwImage.DistortedTanWcs)
del exposure
del outWcs
# return the original pure TAN WCS if the exposure's detector has no
# TAN_PIXELS transform
def removeTanPixels(detectorWrapper):
tanPixSys = detector.makeCameraSys(TAN_PIXELS)
detectorWrapper.transMap.pop(tanPixSys)
detectorNoTanPix = DetectorWrapper(modFunc=removeTanPixels).detector
exposure = afwImage.ExposureF(10, 10)
exposure.setWcs(self.tanWcs)
exposure.setDetector(detectorNoTanPix)
outWcs = getDistortedWcs(exposure.getInfo())
self.assertFalse(outWcs.hasDistortion())
self.assertIsInstance(outWcs, afwImage.TanWcs)
self.assertNotIsInstance(outWcs, afwImage.DistortedTanWcs)
del exposure
del outWcs
def testGetDistortedWcs(self):
"""Test utils.getDistortedWcs
"""
dw = DetectorWrapper()
detector = dw.detector
# the standard case: the exposure's WCS is pure TAN WCS and distortion information is available;
# return a DistortedTanWcs
exposure = afwImage.ExposureF(10, 10)
exposure.setDetector(detector)
exposure.setWcs(self.tanWcs)
self.assertFalse(self.tanWcs.hasDistortion())
outWcs = getDistortedWcs(exposure.getInfo())
self.assertTrue(outWcs.hasDistortion())
self.assertTrue(afwImage.DistortedTanWcs.cast(outWcs) is not None)
del exposure # avoid accidental reuse
del outWcs
# return the original WCS if the exposure's WCS has distortion
pixelsToTanPixels = afwGeom.RadialXYTransform([0, 1.001, 0.00003])
distortedWcs = afwImage.DistortedTanWcs(self.tanWcs, pixelsToTanPixels)
self.assertTrue(distortedWcs.hasDistortion())
exposure = afwImage.ExposureF(10, 10)
exposure.setWcs(distortedWcs)
exposure.setDetector(detector)
outWcs = getDistortedWcs(exposure.getInfo())
self.assertTrue(outWcs.hasDistortion())
self.assertTrue(afwImage.DistortedTanWcs.cast(outWcs) is not None)
del exposure
del distortedWcs
del outWcs
# raise an exception if exposure has no WCS
exposure = afwImage.ExposureF(10, 10)
exposure.setDetector(detector)
self.assertRaises(Exception, getDistortedWcs, exposure.getInfo())
del exposure
# return the original pure TAN WCS if the exposure has no detector
exposure = afwImage.ExposureF(10, 10)
exposure.setWcs(self.tanWcs)
outWcs = getDistortedWcs(exposure.getInfo())
self.assertFalse(outWcs.hasDistortion())
self.assertTrue(afwImage.TanWcs.cast(outWcs) is not None)
self.assertTrue(afwImage.DistortedTanWcs.cast(outWcs) is None)
del exposure
del outWcs
# return the original pure TAN WCS if the exposure's detector has no TAN_PIXELS transform
def removeTanPixels(detectorWrapper):
tanPixSys = detector.makeCameraSys(TAN_PIXELS)
detectorWrapper.transMap.pop(tanPixSys)
detectorNoTanPix = DetectorWrapper(modFunc=removeTanPixels).detector
exposure = afwImage.ExposureF(10, 10)
exposure.setWcs(self.tanWcs)
exposure.setDetector(detectorNoTanPix)
outWcs = getDistortedWcs(exposure.getInfo())
self.assertFalse(outWcs.hasDistortion())
self.assertTrue(afwImage.TanWcs.cast(outWcs) is not None)
self.assertTrue(afwImage.DistortedTanWcs.cast(outWcs) is None)
del exposure
del outWcs
