LSST Applications  21.0.0-172-gfb10e10a+18fedfabac,22.0.0+297cba6710,22.0.0+80564b0ff1,22.0.0+8d77f4f51a,22.0.0+a28f4c53b1,22.0.0+dcf3732eb2,22.0.1-1-g7d6de66+2a20fdde0d,22.0.1-1-g8e32f31+297cba6710,22.0.1-1-geca5380+7fa3b7d9b6,22.0.1-12-g44dc1dc+2a20fdde0d,22.0.1-15-g6a90155+515f58c32b,22.0.1-16-g9282f48+790f5f2caa,22.0.1-2-g92698f7+dcf3732eb2,22.0.1-2-ga9b0f51+7fa3b7d9b6,22.0.1-2-gd1925c9+bf4f0e694f,22.0.1-24-g1ad7a390+a9625a72a8,22.0.1-25-g5bf6245+3ad8ecd50b,22.0.1-25-gb120d7b+8b5510f75f,22.0.1-27-g97737f7+2a20fdde0d,22.0.1-32-gf62ce7b1+aa4237961e,22.0.1-4-g0b3f228+2a20fdde0d,22.0.1-4-g243d05b+871c1b8305,22.0.1-4-g3a563be+32dcf1063f,22.0.1-4-g44f2e3d+9e4ab0f4fa,22.0.1-42-gca6935d93+ba5e5ca3eb,22.0.1-5-g15c806e+85460ae5f3,22.0.1-5-g58711c4+611d128589,22.0.1-5-g75bb458+99c117b92f,22.0.1-6-g1c63a23+7fa3b7d9b6,22.0.1-6-g50866e6+84ff5a128b,22.0.1-6-g8d3140d+720564cf76,22.0.1-6-gd805d02+cc5644f571,22.0.1-8-ge5750ce+85460ae5f3,master-g6e05de7fdc+babf819c66,master-g99da0e417a+8d77f4f51a,w.2021.48
LSST Data Management Base Package
Public Member Functions | Public Attributes | List of all members
lsst.meas.algorithms.brightStarStamps.BrightStarStamp Class Reference
Inheritance diagram for lsst.meas.algorithms.brightStarStamps.BrightStarStamp:
lsst.meas.algorithms.stamps.AbstractStamp

Public Member Functions

def factory (cls, stamp_im, metadata, idx, archive_element=None)
 
def measureAndNormalize (self, annulus, statsControl=afwMath.StatisticsControl(), statsFlag=afwMath.stringToStatisticsProperty("MEAN"), badMaskPlanes=('BAD', 'SAT', 'NO_DATA'))
 

Public Attributes

 annularFlux
 

Detailed Description

Single stamp centered on a bright star, normalized by its
annularFlux.

Parameters
----------
stamp_im : `lsst.afw.image.MaskedImage`
    Pixel data for this postage stamp
position : `lsst.geom.Point2I`
    Origin of the stamps in its origin exposure (pixels)
gaiaGMag : `float`
    Gaia G magnitude for the object in this stamp
gaiaId : `int`
    Gaia object identifier
annularFlux : `Optional[float]`
    Flux in an annulus around the object

Definition at line 42 of file brightStarStamps.py.

Member Function Documentation

◆ factory()

def lsst.meas.algorithms.brightStarStamps.BrightStarStamp.factory (   cls,
  stamp_im,
  metadata,
  idx,
  archive_element = None 
)
This method is needed to service the FITS reader.
We need a standard interface to construct objects like this.
Parameters needed to construct this object are passed in via
a metadata dictionary and then passed to the constructor of
this class.  This particular factory method requires keys:
G_MAGS, GAIA_IDS, and ANNULAR_FLUXES.  They should each
point to lists of values.

Parameters
----------
stamp_im : `lsst.afw.image.MaskedImage`
    Pixel data to pass to the constructor
metadata : `dict`
    Dictionary containing the information
    needed by the constructor.
idx : `int`
    Index into the lists in ``metadata``
archive_element : `lsst.afwTable.io.Persistable`, optional
    Archive element (e.g. Transform or WCS) associated with this stamp.

Returns
-------
brightstarstamp : `BrightStarStamp`
    An instance of this class

Reimplemented from lsst.meas.algorithms.stamps.AbstractStamp.

Definition at line 67 of file brightStarStamps.py.

67  def factory(cls, stamp_im, metadata, idx, archive_element=None):
68  """This method is needed to service the FITS reader.
69  We need a standard interface to construct objects like this.
70  Parameters needed to construct this object are passed in via
71  a metadata dictionary and then passed to the constructor of
72  this class. This particular factory method requires keys:
73  G_MAGS, GAIA_IDS, and ANNULAR_FLUXES. They should each
74  point to lists of values.
75 
76  Parameters
77  ----------
78  stamp_im : `lsst.afw.image.MaskedImage`
79  Pixel data to pass to the constructor
80  metadata : `dict`
81  Dictionary containing the information
82  needed by the constructor.
83  idx : `int`
84  Index into the lists in ``metadata``
85  archive_element : `lsst.afwTable.io.Persistable`, optional
86  Archive element (e.g. Transform or WCS) associated with this stamp.
87 
88  Returns
89  -------
90  brightstarstamp : `BrightStarStamp`
91  An instance of this class
92  """
93  if 'X0S' in metadata and 'Y0S' in metadata:
94  x0 = metadata.getArray('X0S')[idx]
95  y0 = metadata.getArray('Y0S')[idx]
96  position = Point2I(x0, y0)
97  else:
98  position = None
99  return cls(stamp_im=stamp_im,
100  gaiaGMag=metadata.getArray('G_MAGS')[idx],
101  gaiaId=metadata.getArray('GAIA_IDS')[idx],
102  position=position,
103  archive_element=archive_element,
104  annularFlux=metadata.getArray('ANNULAR_FLUXES')[idx])
105 
Point< int, 2 > Point2I
Definition: Point.h:321

◆ measureAndNormalize()

def lsst.meas.algorithms.brightStarStamps.BrightStarStamp.measureAndNormalize (   self,
  annulus,
  statsControl = afwMath.StatisticsControl(),
  statsFlag = afwMath.stringToStatisticsProperty("MEAN"),
  badMaskPlanes = ('BAD', 'SAT', 'NO_DATA') 
)
Compute "annularFlux", the integrated flux within an annulus
around an object's center, and normalize it.

Since the center of bright stars are saturated and/or heavily affected
by ghosts, we measure their flux in an annulus with a large enough
inner radius to avoid the most severe ghosts and contain enough
non-saturated pixels.

Parameters
----------
annulus : `lsst.afw.geom.spanSet.SpanSet`
    SpanSet containing the annulus to use for normalization.
statsControl : `lsst.afw.math.statistics.StatisticsControl`, optional
    StatisticsControl to be used when computing flux over all pixels
    within the annulus.
statsFlag : `lsst.afw.math.statistics.Property`, optional
    statsFlag to be passed on to ``afwMath.makeStatistics`` to compute
    annularFlux. Defaults to a simple MEAN.
badMaskPlanes : `collections.abc.Collection` [`str`]
    Collection of mask planes to ignore when computing annularFlux.

Definition at line 106 of file brightStarStamps.py.

108  badMaskPlanes=('BAD', 'SAT', 'NO_DATA')):
109  """Compute "annularFlux", the integrated flux within an annulus
110  around an object's center, and normalize it.
111 
112  Since the center of bright stars are saturated and/or heavily affected
113  by ghosts, we measure their flux in an annulus with a large enough
114  inner radius to avoid the most severe ghosts and contain enough
115  non-saturated pixels.
116 
117  Parameters
118  ----------
119  annulus : `lsst.afw.geom.spanSet.SpanSet`
120  SpanSet containing the annulus to use for normalization.
121  statsControl : `lsst.afw.math.statistics.StatisticsControl`, optional
122  StatisticsControl to be used when computing flux over all pixels
123  within the annulus.
124  statsFlag : `lsst.afw.math.statistics.Property`, optional
125  statsFlag to be passed on to ``afwMath.makeStatistics`` to compute
126  annularFlux. Defaults to a simple MEAN.
127  badMaskPlanes : `collections.abc.Collection` [`str`]
128  Collection of mask planes to ignore when computing annularFlux.
129  """
130  stampSize = self.stamp_im.getDimensions()
131  # create image with the same pixel values within annulus, NO_DATA
132  # elsewhere
133  maskPlaneDict = self.stamp_im.mask.getMaskPlaneDict()
134  annulusImage = MaskedImageF(stampSize, planeDict=maskPlaneDict)
135  annulusMask = annulusImage.mask
136  annulusMask.array[:] = 2**maskPlaneDict['NO_DATA']
137  annulus.copyMaskedImage(self.stamp_im, annulusImage)
138  # set mask planes to be ignored
139  andMask = reduce(ior, (annulusMask.getPlaneBitMask(bm) for bm in badMaskPlanes))
140  statsControl.setAndMask(andMask)
141  # compute annularFlux
142  annulusStat = afwMath.makeStatistics(annulusImage, statsFlag, statsControl)
143  self.annularFlux = annulusStat.getValue()
144  if np.isnan(self.annularFlux):
145  raise RuntimeError("Annular flux computation failed, likely because no pixels were valid.")
146  # normalize stamps
147  self.stamp_im.image.array /= self.annularFlux
148  return None
149 
150 
Statistics makeStatistics(lsst::afw::image::Image< Pixel > const &img, lsst::afw::image::Mask< image::MaskPixel > const &msk, int const flags, StatisticsControl const &sctrl=StatisticsControl())
Handle a watered-down front-end to the constructor (no variance)
Definition: Statistics.h:359

Member Data Documentation

◆ annularFlux

lsst.meas.algorithms.brightStarStamps.BrightStarStamp.annularFlux

Definition at line 143 of file brightStarStamps.py.


The documentation for this class was generated from the following file: