Class PsfFluxAlgorithm

Inheritance Relationships

Base Type

Class Documentation

class PsfFluxAlgorithm : public lsst::meas::base::SimpleAlgorithm

A measurement algorithm that estimates instFlux using a linear least-squares fit with the Psf model.

The PsfFlux algorithm is extremely simple: we do a least-squares fit of the Psf model (evaluated at a given position) to the data. For point sources, this provides the optimal instFlux measurement in the limit where the Psf model is correct. We do not use per-pixel weights in the fit, as this results in bright stars being fit with a different effective profile than faint stairs.

Public Types

typedef PsfFluxControl Control

A typedef to the Control object for this algorithm, defined above. The control object contains the configuration parameters for this algorithm.

Public Functions

PsfFluxAlgorithm(Control const &ctrl, std::string const &name, afw::table::Schema &schema, std::string const &logName = "")
virtual void measure(afw::table::SourceRecord &measRecord, afw::image::Exposure<float> const &exposure) const

Called to measure a single child source in an image.

Before this method is called, all neighbors will be replaced with noise, using the outputs of the deblender. Outputs should be saved in the given SourceRecord, which can also be used to obtain centroid (see SafeCentroidExtractor) and shape (see SafeShapeExtractor) information.

virtual void fail(afw::table::SourceRecord &measRecord, MeasurementError *error = nullptr) const

Handle an exception thrown by the current algorithm by setting flags in the given record.

fail() is called by the measurement framework when an exception is allowed to propagate out of one the algorithm’s measure() methods. It should generally set both a general failure flag for the algorithm as well as a specific flag indicating the error condition, if possible. To aid in this, if the exception was an instance of MeasurementError, it will be passed in, carrying information about what flag to set.

An algorithm can also to chose to set flags within its own measure() methods, and then just return, rather than throw an exception. However, fail() should be implemented even when all known failure modes do not throw exceptions, to ensure that unexpected exceptions thrown in lower-level code are properly handled.

Public Static Functions

static FlagDefinitionList const &getFlagDefinitions()

Public Static Attributes

FlagDefinition const FAILURE
FlagDefinition const NO_GOOD_PIXELS
FlagDefinition const EDGE