Coverage for python/lsst/meas/base/classification.py: 48%

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1# This file is part of meas_base. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (https://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# This program is free software: you can redistribute it and/or modify 

10# it under the terms of the GNU General Public License as published by 

11# the Free Software Foundation, either version 3 of the License, or 

12# (at your option) any later version. 

13# 

14# This program is distributed in the hope that it will be useful, 

15# but WITHOUT ANY WARRANTY; without even the implied warranty of 

16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

17# GNU General Public License for more details. 

18# 

19# You should have received a copy of the GNU General Public License 

20# along with this program. If not, see <https://www.gnu.org/licenses/>. 

21 

22"""Definition and registration of classification plugins. 

23""" 

24 

25import numpy as np 

26 

27import lsst.pex.config 

28from .catalogCalculation import CatalogCalculationPluginConfig, CatalogCalculationPlugin 

29from .pluginRegistry import register 

30 

31__all__ = ( 

32 "CatalogCalculationClassificationConfig", "CatalogCalculationClassificationPlugin", 

33) 

34 

35 

36class CatalogCalculationClassificationConfig(CatalogCalculationPluginConfig): 

37 """Configuration for catalog classification plugin. 

38 """ 

39 

40 fluxRatio = lsst.pex.config.Field(dtype=float, default=.925, optional=True, 

41 doc="critical ratio of model to psf flux") 

42 modelErrFactor = lsst.pex.config.Field(dtype=float, default=0.0, optional=True, 

43 doc="correction factor for modelFlux error") 

44 psfErrFactor = lsst.pex.config.Field(dtype=float, default=0.0, optional=True, 

45 doc="correction factor for psfFlux error") 

46 

47 

48@register("base_ClassificationExtendedness") 

49class CatalogCalculationClassificationPlugin(CatalogCalculationPlugin): 

50 """Plugin which calculates a binary measure of source extendedness. 

51 

52 Extendedness is based on a simple cut of the ratio of the PSF flux to the 

53 model flux. 

54 

55 Notes 

56 ----- 

57 Because the fluxes on which this algorithm is based on are slot 

58 measurements, they can be provided by different algorithms, and the 

59 `~CatalogCalculationClassificationConfig.fluxRatio` threshold used by this 

60 algorithm should generally be set differently for different algorithms. 

61 To do this, plot the difference between the PSF magnitude and the model 

62 magnitude vs. the PSF magnitude, and look for where the cloud of galaxies 

63 begins. 

64 """ 

65 

66 ConfigClass = CatalogCalculationClassificationConfig 

67 

68 @classmethod 

69 def getExecutionOrder(cls): 

70 return cls.DEFAULT_CATALOGCALCULATION 

71 

72 def __init__(self, config, name, schema, metadata): 

73 CatalogCalculationPlugin.__init__(self, config, name, schema, metadata) 

74 self.keyProbability = schema.addField(name + "_value", type="D", 

75 doc="Set to 1 for extended sources, 0 for point sources.") 

76 self.keyFlag = schema.addField(name + "_flag", type="Flag", doc="Set to 1 for any fatal failure.") 

77 

78 def calculate(self, measRecord): 

79 modelFlux = measRecord.getModelInstFlux() 

80 psfFlux = measRecord.getPsfInstFlux() 

81 modelFluxFlag = (measRecord.getModelFluxFlag() 

82 if measRecord.table.getModelFluxSlot().isValid() 

83 else False) 

84 psfFluxFlag = (measRecord.getPsfFluxFlag() 

85 if measRecord.table.getPsfFluxSlot().isValid() 

86 else False) 

87 flux1 = self.config.fluxRatio*modelFlux 

88 if self.config.modelErrFactor != 0: 

89 flux1 += self.config.modelErrFactor*measRecord.getModelInstFluxErr() 

90 flux2 = psfFlux 

91 if not self.config.psfErrFactor == 0: 

92 flux2 += self.config.psfErrFactor*measRecord.getPsfInstFluxErr() 

93 

94 # A generic failure occurs when either FluxFlag is set to True 

95 # A generic failure also occurs if either calculated flux value is NaN: 

96 # this can occur if the Flux field itself is NaN, 

97 # or the ErrFactor != 0 and the FluxErr is NaN 

98 if np.isnan(flux1) or np.isnan(flux2) or modelFluxFlag or psfFluxFlag: 

99 self.fail(measRecord) 

100 else: 

101 measRecord.set(self.keyProbability, 0.0 if flux1 < flux2 else 1.0) 

102 

103 def fail(self, measRecord, error=None): 

104 measRecord.set(self.keyFlag, True)