SingleFrameMomentsClassifierPlugin¶
- class lsst.meas.base.SingleFrameMomentsClassifierPlugin(config, name, schema, metadata)¶
Bases:
SingleFramePlugin
Classify objects by comparing their moments-based trace radius to PSF’s.
The plugin computes chi^2 as ((T_obj - T_psf)/T_psf^exponent)^2, where T_obj is the sum of Ixx and Iyy moments of the object, and T_psf is the sum of Ixx and Iyy moments of the PSF. The exponent is configurable. The measure of being a galaxy is then 1 - exp(-0.5*chi^2).
- Parameters:
Notes
The
measure
method of the plugin requires a value for theexposure
argument to maintain consistent API, but it is not used in the measurement.Attributes Summary
Order for algorithms which require shape, centroid and flux (
float
).Order for algorithms which require only Footprint and Peaks (
float
).Order for catalog calculation plugins.
Order for algorithms which require a shape and a centroid (
float
).Order for algorithms which require a centroid (
float
).Registry of subclasses of
SingleFramePlugin
(PluginRegistry
).Methods Summary
fail
(measRecord[, error])Get the relative execution order of this plugin.
Get the measurement transformation appropriate to this plugin.
measure
(measRecord, exposure)Measure the properties of a source on a single image.
measureN
(measCat, exposure)Measure the properties of blended sources on a single image.
Attributes Documentation
- APCORR_ORDER = 3.0¶
Order for algorithms which require shape, centroid and flux (
float
).Notes
These algorithms may assume that
getCentroid
andgetShape
will return good values, that flux has been measured, and that and that a Footprint and its Peaks are available.
- CENTROID_ORDER = 0.0¶
Order for algorithms which require only Footprint and Peaks (
float
).Notes
Algorithms with this execution order include centroids.
- DEFAULT_CATALOGCALCULATION = 4.0¶
Order for catalog calculation plugins.
Notes
These plugins only operate on catalogs; they may not access pixel values.
- FLUX_ORDER = 2.0¶
Order for algorithms which require a shape and a centroid (
float
).Notes
These algorithms may assume that both
getCentroid
andgetShape
will return good values, and that a Footprint and its Peaks are available.
- SHAPE_ORDER = 1.0¶
Order for algorithms which require a centroid (
float
).Notes
These algorithms may refer assume that
getCentroid
will return a good centroid, and that a Footprint and its Peaks are available.
- registry = <lsst.meas.base.pluginRegistry.PluginRegistry object>¶
Registry of subclasses of
SingleFramePlugin
(PluginRegistry
).
Methods Documentation
- fail(measRecord, error=None) None ¶
Record a failure of the
measure
ormeasureN
method.- Parameters:
- measRecord
lsst.afw.table.SourceRecord
Table record describing the source being measured.
- error
MeasurementError
, optional Only provided if the measurement failed due to a
MeasurementError
being raised; otherwise, will beNone
.
- measRecord
Notes
When the plugin raises an exception, framework will call
BasePlugin.fail
to allow the plugin to set its failure flag field(s). WhenBasePlugin.measureN
raises an exception,BasePlugin.fail
will be called repeatedly with all the records that were being measured.If the exception is an
MeasurementError
, it will be passed as the error argument; in all other cases the error argument will beNone
, and the failure will be logged by the measurement framework as a warning.
- classmethod getExecutionOrder()¶
Get the relative execution order of this plugin.
Must be reimplemented as a class method by concrete derived classes.
- getLogName()¶
- static getTransformClass()¶
Get the measurement transformation appropriate to this plugin.
This returns a subclass of
transforms.MeasurementTransform
, which may be instantiated with details of the algorithm configuration and then called with information about calibration and WCS to convert from raw measurement quantities to calibrated units. Calibrated data is then provided in a separate output table.Notes
By default, we copy everything from the input to the output without transformation.
- measure(measRecord, exposure) None ¶
Measure the properties of a source on a single image.
The image may be from a single epoch, or it may be a coadd.
- Parameters:
- measRecord
lsst.afw.table.SourceRecord
Record describing the object being measured. Previously-measured quantities may be retrieved from here, and it will be updated in-place tih the outputs of this plugin.
- exposure
lsst.afw.image.ExposureF
The pixel data to be measured, together with the associated PSF, WCS, etc. All other sources in the image should have been replaced by noise according to deblender outputs.
- measRecord
- measureN(measCat, exposure)¶
Measure the properties of blended sources on a single image.
This operates on all members of a blend family at once. The image may be from a single epoch, or it may be a coadd.
- Parameters:
- measCat
lsst.afw.table.SourceCatalog
Catalog describing the objects (and only those objects) being measured. Previously-measured quantities will be retrieved from here, and it will be updated in-place with the outputs of this plugin.
- exposure
lsst.afw.image.ExposureF
The pixel data to be measured, together with the associated PSF, WCS, etc. All other sources in the image should have been replaced by noise according to deblender outputs.
- measCat
Notes
Derived classes that do not implement
measureN
should just inherit this disabled version. Derived classes that do implementmeasureN
should additionally add a bool doMeasureN config field to their config class to signal that measureN-mode is available.