lsst.meas.astrom ga6835749f4+0a9654e073
Public Member Functions | Public Attributes | List of all members
lsst.meas.astrom.pessimistic_pattern_matcher_b_3D.PessimisticPatternMatcherB Class Reference

Public Member Functions

def __init__ (self, reference_array, log)
 
def match (self, source_array, n_check, n_match, n_agree, max_n_patterns, max_shift, max_rotation, max_dist, min_matches, pattern_skip_array=None)
 

Public Attributes

 log
 

Detailed Description

Class implementing a pessimistic version of Optimistic Pattern Matcher
B (OPMb) from `Tabur (2007)`_, as described in `DMTN-031`_

Parameters
----------
reference_array : `numpy.ndarray`, (N, 3)
    spherical points x, y, z of to use as reference objects for
    pattern matching.
log : `lsst.log.Log` or `logging.Logger`
    Logger for outputting debug info.

Notes
-----
The class loads and stores the reference object
in a convenient data structure for matching any set of source objects that
are assumed to contain each other. The pessimistic nature of the algorithm
comes from requiring that it discovers at least two patterns that agree on
the correct shift and rotation for matching before exiting. The original
behavior of OPMb can be recovered simply. Patterns matched between the
input datasets are n-spoked pinwheels created from n+1 points. Refer to
`DMTN-031`_ for more details.

.. _Tabur (2007): https://doi.org/10.1071/AS07028
.. _DMTN-031: https://dmtn-031.lsst.io/

Definition at line 77 of file pessimistic_pattern_matcher_b_3D.py.

Constructor & Destructor Documentation

◆ __init__()

def lsst.meas.astrom.pessimistic_pattern_matcher_b_3D.PessimisticPatternMatcherB.__init__ (   self,
  reference_array,
  log 
)

Definition at line 104 of file pessimistic_pattern_matcher_b_3D.py.

Member Function Documentation

◆ match()

def lsst.meas.astrom.pessimistic_pattern_matcher_b_3D.PessimisticPatternMatcherB.match (   self,
  source_array,
  n_check,
  n_match,
  n_agree,
  max_n_patterns,
  max_shift,
  max_rotation,
  max_dist,
  min_matches,
  pattern_skip_array = None 
)
Match a given source catalog into the loaded reference catalog.

Given array of points on the unit sphere and tolerances, we
attempt to match a pinwheel like pattern between these input sources
and the reference objects this class was created with. This pattern
informs of the shift and rotation needed to align the input source
objects into the frame of the references.

Parameters
----------
source_array : `numpy.ndarray`, (N, 3)
    An array of spherical x,y,z coordinates and a magnitude in units
    of objects having a lower value for sorting. The array should be
    of shape (N, 4).
n_check  : `int`
    Number of sources to create a pattern from. Not all objects may be
    checked if n_match criteria is before looping through all n_check
    objects.
n_match : `int`
    Number of objects to use in constructing a pattern to match.
n_agree : `int`
    Number of found patterns that must agree on their shift and
    rotation before exiting. Set this value to 1 to recover the
    expected behavior of Optimistic Pattern Matcher B.
max_n_patters : `int`
    Number of patterns to create from the input source objects to
    attempt to match into the reference objects.
max_shift : `float`
    Maximum allowed shift to match patterns in arcseconds.
max_rotation : `float`
    Maximum allowed rotation between patterns in degrees.
max_dist : `float`
    Maximum distance in arcseconds allowed between candidate spokes in
    the source and reference objects. Also sets that maximum distance
    in the intermediate verify, pattern shift/rotation agreement, and
    final verify steps.
pattern_skip_array : `int`
    Patterns we would like to skip. This could be due to the pattern
    being matched on a previous iteration that we now consider invalid.
    This assumes the ordering of the source objects is the same
    between different runs of the matcher which, assuming no object
    has been inserted or the magnitudes have changed, it should be.

Returns
-------
output_struct : `lsst.pipe.base.Struct`
    Result struct with components

    - ``matches`` : (N, 2) array of matched ids for pairs. Empty list if no
      match found (`numpy.ndarray`, (N, 2) or `list`)
    - ``distances_rad`` : Radian distances between the matched objects.
      Empty list if no match found (`numpy.ndarray`, (N,))
    - ``pattern_idx``: Index of matched pattern. None if no match found
      (`int`).
    - ``shift`` : Magnitude for the shift between the source and reference
      objects in arcseconds. None if no match found (`float`).

Definition at line 160 of file pessimistic_pattern_matcher_b_3D.py.

Member Data Documentation

◆ log

lsst.meas.astrom.pessimistic_pattern_matcher_b_3D.PessimisticPatternMatcherB.log

Definition at line 107 of file pessimistic_pattern_matcher_b_3D.py.


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