LSSTApplications  18.1.0
LSSTDataManagementBasePackage
makePsfCandidates.py
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23 __all__ = ["MakePsfCandidatesConfig", "MakePsfCandidatesTask"]
24 
25 import numpy as np
26 
27 from lsst.afw.table import SourceCatalog
28 import lsst.afw.math as afwMath
29 import lsst.pex.config as pexConfig
31 import lsst.pipe.base as pipeBase
32 from . import makePsfCandidate
33 
34 
35 class MakePsfCandidatesConfig(pexConfig.Config):
36  kernelSize = pexConfig.Field(
37  doc="size of the kernel to create",
38  dtype=int,
39  default=21,
40  )
41  borderWidth = pexConfig.Field(
42  doc="number of pixels to ignore around the edge of PSF candidate postage stamps",
43  dtype=int,
44  default=0,
45  )
46 
47 
48 class MakePsfCandidatesTask(pipeBase.Task):
49  """Create PSF candidates given an input catalog.
50  """
51  ConfigClass = MakePsfCandidatesConfig
52  _DefaultName = "makePsfCandidates"
53 
54  def __init__(self, **kwds):
55  pipeBase.Task.__init__(self, **kwds)
56 
57  def run(self, starCat, exposure, psfCandidateField=None):
58  """Make a list of PSF candidates from a star catalog.
59 
60  Parameters
61  ----------
62  starCat : `lsst.afw.table.SourceCatalog`
63  Catalog of stars, as returned by
64  ``lsst.meas.algorithms.starSelector.run()``.
65  exposure : `lsst.afw.image.Exposure`
66  The exposure containing the sources.
67  psfCandidateField : `str` or None
68  Name of flag field to set True for PSF candidates, or None to not
69  set a field; the field is left unchanged for non-candidates.
70 
71  Returns
72  -------
73  struct : `lsst.pipe.base.Struct`
74  Results struct containing:
75 
76  - ``psfCandidates`` : List of PSF candidates
77  (`list` of `lsst.meas.algorithms.PsfCandidate`).
78  - ``goodStarCat`` : Subset of ``starCat`` that was successfully made
79  into PSF candidates (`lsst.afw.table.SourceCatalog`).
80 
81  """
82  psfResult = self.makePsfCandidates(starCat, exposure)
83 
84  if psfCandidateField is not None:
85  isStarKey = starCat.schema[psfCandidateField].asKey()
86  for star in psfResult.goodStarCat:
87  star.set(isStarKey, True)
88 
89  return psfResult
90 
91  def makePsfCandidates(self, starCat, exposure):
92  """Make a list of PSF candidates from a star catalog.
93 
94  Parameters
95  ----------
96  starCat : `lsst.afw.table.SourceCatalog`
97  Catalog of stars, as returned by
98  ``lsst.meas.algorithms.starSelector.run()``.
99  exposure : `lsst.afw.image.Exposure`
100  The exposure containing the sources.
101 
102  Returns
103  -------
104  struct : `lsst.pipe.base.Struct`
105  Results struct containing:
106 
107  - ``psfCandidates`` : List of PSF candidates
108  (`list` of `lsst.meas.algorithms.PsfCandidate`).
109  - ``goodStarCat`` : Subset of ``starCat`` that was successfully made
110  into PSF candidates (`lsst.afw.table.SourceCatalog`).
111  """
112  goodStarCat = SourceCatalog(starCat.schema)
113 
114  psfCandidateList = []
115  didSetSize = False
116  for star in starCat:
117  try:
118  psfCandidate = makePsfCandidate(star, exposure)
119 
120  # The setXXX methods are class static, but it's convenient to call them on
121  # an instance as we don't know exposures's pixel type
122  # (and hence psfCandidate's exact type)
123  if not didSetSize:
124  psfCandidate.setBorderWidth(self.config.borderWidth)
125  psfCandidate.setWidth(self.config.kernelSize + 2*self.config.borderWidth)
126  psfCandidate.setHeight(self.config.kernelSize + 2*self.config.borderWidth)
127  didSetSize = True
128 
129  im = psfCandidate.getMaskedImage().getImage()
130  except lsst.pex.exceptions.Exception as err:
131  self.log.warn("Failed to make a psfCandidate from star %d: %s", star.getId(), err)
132  continue
133 
134  vmax = afwMath.makeStatistics(im, afwMath.MAX).getValue()
135  if not np.isfinite(vmax):
136  continue
137  psfCandidateList.append(psfCandidate)
138  goodStarCat.append(star)
139 
140  return pipeBase.Struct(
141  psfCandidates=psfCandidateList,
142  goodStarCat=goodStarCat,
143  )
Provides consistent interface for LSST exceptions.
Definition: Exception.h:107
Statistics makeStatistics(lsst::afw::math::MaskedVector< EntryT > const &mv, std::vector< WeightPixel > const &vweights, int const flags, StatisticsControl const &sctrl=StatisticsControl())
The makeStatistics() overload to handle lsst::afw::math::MaskedVector<>
Definition: Statistics.h:520
std::shared_ptr< PsfCandidate< PixelT > > makePsfCandidate(boost::shared_ptr< afw::table::SourceRecord > const &source, boost::shared_ptr< afw::image::Exposure< PixelT > > image)
Return a PsfCandidate of the right sort.
Definition: PsfCandidate.h:178
def run(self, starCat, exposure, psfCandidateField=None)