LSSTApplications  18.1.0
LSSTDataManagementBasePackage
psfDeterminer.py
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23 
24 __all__ = ["BasePsfDeterminerConfig", "BasePsfDeterminerTask", "psfDeterminerRegistry"]
25 
26 import abc
27 
28 import lsst.pipe.base as pipeBase
29 import lsst.pex.config as pexConfig
30 
31 
32 class BasePsfDeterminerConfig(pexConfig.Config):
33  """Configuration that is likely to be shared by all PSF determiners
34 
35  This is fairly sparse; more fields can be moved here once it is clear they are universal.
36  """
37  kernelSize = pexConfig.Field(
38  doc="radius of the kernel to create, relative to the square root of the stellar quadrupole moments",
39  dtype=float,
40  default=10.0,
41  )
42  kernelSizeMin = pexConfig.Field(
43  doc="Minimum radius of the kernel",
44  dtype=int,
45  default=25,
46  )
47  kernelSizeMax = pexConfig.Field(
48  doc="Maximum radius of the kernel",
49  dtype=int,
50  default=45,
51  )
52 
53 
54 class BasePsfDeterminerTask(pipeBase.Task, metaclass=abc.ABCMeta):
55  """!Base class for PSF determiners
56 
57  Register all PSF determiners with the psfDeterminerRegistry using:
58  psfDeterminerRegistry.register(name, class)
59  """
60 
61  usesMatches = False # Does the PSF determiner use the "matches" argument in the "run method? Few do.
62  ConfigClass = BasePsfDeterminerConfig
63  _DefaultName = "psfDeterminer"
64 
65  def __init__(self, config, schema=None, **kwds):
66  """Construct a PSF Determiner
67 
68  @param[in] config an instance of pexConfig.Config that configures this algorithm
69  @param[in,out] schema an instance of afw.table.Schema used for sources; passing a
70  schema allows the determiner to reserve a flag field to mark stars
71  used in PSF measurement, but some PSF determiners ignore this argument
72  """
73  pipeBase.Task.__init__(self, config=config, **kwds)
74 
75  @abc.abstractmethod
76  def determinePsf(self, exposure, psfCandidateList, metadata=None):
77  """Determine a PSF model
78 
79  @param[in] exposure exposure containing the psf candidates (lsst.afw.image.Exposure)
80  @param[in] psfCandidateList: a sequence of PSF candidates (each an
81  lsst.meas.algorithms.PsfCandidate); typically obtained by
82  detecting sources and then running them through a star selector
83  @param[in,out] metadata a place to save interesting items
84 
85  @return
86  - psf: the fit PSF; a subclass of lsst.afw.detection.Psf
87  - cellSet: the spatial cell set used to determine the PSF (lsst.afw.math.SpatialCellSet)
88  """
89  raise NotImplementedError("BasePsfDeterminerTask is abstract, subclasses must override this method")
90 
91 
92 psfDeterminerRegistry = pexConfig.makeRegistry(
93  doc="A registry of PSF determiners (subclasses of BasePsfDeterminerTask)",
94 )
def determinePsf(self, exposure, psfCandidateList, metadata=None)