SingleFrameJacobianPlugin

class lsst.meas.base.SingleFrameJacobianPlugin(config, name, schema, metadata)

Bases: lsst.meas.base.SingleFramePlugin

Compute the Jacobian and its ratio with a nominal pixel area.

This enables one to compare relative, rather than absolute, pixel areas.

Parameters:

config : SingleFrameJacobianConfig

Plugin configuraion.

name : str

Plugin name.

schema : lsst.afw.table.Schema

The schema for the measurement output catalog. New fields will be added to hold measurements produced by this plugin.

metadata : lsst.daf.base.PropertySet

Plugin metadata that will be attached to the output catalog

Attributes Summary

APCORR_ORDER
CENTROID_ORDER
DEFAULT_CATALOGCALCULATION
FLUX_ORDER
SHAPE_ORDER
registry

Methods Summary

fail(measRecord[, error])	Record a failure of the measure or measureN method.
getExecutionOrder()	Get the relative execution order of this plugin.
getLogName()
getTransformClass()	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

CENTROID_ORDER = 0.0

DEFAULT_CATALOGCALCULATION = 4.0

FLUX_ORDER = 2.0

SHAPE_ORDER = 1.0

registry = <lsst.meas.base.pluginRegistry.PluginRegistry object>

Methods Documentation

fail(measRecord, error=None)

Record a failure of the measure or measureN 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 be None.

Notes

When the plugin raises an exception, framework will call BasePlugin.fail to allow the plugin to set its failure flag field(s). When BasePlugin.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 be None, 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)

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.

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.

Notes

Derived classes that do not implement measureN should just inherit this disabled version. Derived classes that do implement measureN should additionally add a bool doMeasureN config field to their config class to signal that measureN-mode is available.