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LSST Data Management Base Package
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Public Types | Public Member Functions | Static Public Member Functions | Static Public Attributes | Protected Attributes | List of all members
lsst::meas::base::PeakLikelihoodFluxAlgorithm Class Reference

A measurement algorithm that estimates the peak instrument flux, using a filtered image which has been convolved with its own PSF. More...

#include <PeakLikelihoodFlux.h>

Inheritance diagram for lsst::meas::base::PeakLikelihoodFluxAlgorithm:
lsst::meas::base::SimpleAlgorithm lsst::meas::base::SingleFrameAlgorithm lsst::meas::base::ForcedAlgorithm lsst::meas::base::BaseAlgorithm lsst::meas::base::BaseAlgorithm

Public Types

typedef PeakLikelihoodFluxControl Control
 A typedef to the Control object for this algorithm, defined above.
 

Public Member Functions

 PeakLikelihoodFluxAlgorithm (Control const &ctrl, std::string const &name, afw::table::Schema &schema)
 
virtual void measure (afw::table::SourceRecord &measRecord, afw::image::Exposure< float > const &exposure) const
 Called to measure a single child source in an image.
 
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.
 
void measureForced (afw::table::SourceRecord &measRecord, afw::image::Exposure< float > const &exposure, afw::table::SourceRecord const &refRecord, afw::geom::SkyWcs const &refWcs) const override
 Called to measure a single child source in an image.
 
void measureNForced (afw::table::SourceCatalog const &measCat, afw::image::Exposure< float > const &exposure, afw::table::SourceCatalog const &refRecord, afw::geom::SkyWcs const &refWcs) const override
 Called to simultaneously measure all children in a deblend family, in a single image.
 
virtual void measureN (afw::table::SourceCatalog const &measCat, afw::image::Exposure< float > const &exposure) const
 Called to simultaneously measure all children in a deblend family, in a single image.
 
std::string getLogName () const
 

Static Public Member Functions

static FlagDefinitionList const & getFlagDefinitions ()
 

Static Public Attributes

static FlagDefinition const FAILURE = flagDefinitions.addFailureFlag()
 

Protected Attributes

std::string _logName
 

Detailed Description

A measurement algorithm that estimates the peak instrument flux, using a filtered image which has been convolved with its own PSF.

Definition at line 71 of file PeakLikelihoodFlux.h.

Member Typedef Documentation

◆ Control

A typedef to the Control object for this algorithm, defined above.

The control object contains the configuration parameters for this algorithm.

Definition at line 79 of file PeakLikelihoodFlux.h.

Constructor & Destructor Documentation

◆ PeakLikelihoodFluxAlgorithm()

lsst::meas::base::PeakLikelihoodFluxAlgorithm::PeakLikelihoodFluxAlgorithm ( Control const & ctrl,
std::string const & name,
afw::table::Schema & schema )

Definition at line 179 of file PeakLikelihoodFlux.cc.

181 : _ctrl(ctrl),
182 _instFluxResultKey(
183 FluxResultKey::addFields(schema, name, "instFlux from PeakLikelihood Flux algorithm")),
184 _centroidExtractor(schema, name) {
185 _flagHandler = FlagHandler::addFields(schema, name, getFlagDefinitions());
186}
static FlagHandler addFields(afw::table::Schema &schema, std::string const &prefix, FlagDefinitionList const &flagDefs, FlagDefinitionList const &exclDefs=FlagDefinitionList::getEmptyList())
Add Flag fields to a schema, creating a FlagHandler object to manage them.
static FluxResultKey addFields(afw::table::Schema &schema, std::string const &name, std::string const &doc)
Add a pair of _instFlux, _instFluxErr fields to a Schema, and return a FluxResultKey that points to t...
static FlagDefinitionList const & getFlagDefinitions()

Member Function Documentation

◆ fail()

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

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.

Implements lsst::meas::base::BaseAlgorithm.

Definition at line 245 of file PeakLikelihoodFlux.cc.

245 {
246 _flagHandler.handleFailure(measRecord, error);
247}
void handleFailure(afw::table::BaseRecord &record, MeasurementError const *error=nullptr) const
Handle an expected or unexpected Exception thrown by a measurement algorithm.

◆ getFlagDefinitions()

FlagDefinitionList const & lsst::meas::base::PeakLikelihoodFluxAlgorithm::getFlagDefinitions ( )
static

Definition at line 45 of file PeakLikelihoodFlux.cc.

45{ return flagDefinitions; }

◆ getLogName()

std::string lsst::meas::base::BaseAlgorithm::getLogName ( ) const
inlineinherited

Definition at line 66 of file Algorithm.h.

66{ return _logName; }

◆ measure()

void lsst::meas::base::PeakLikelihoodFluxAlgorithm::measure ( afw::table::SourceRecord & measRecord,
afw::image::Exposure< float > const & exposure ) const
virtual

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.

Given an image and a pixel position, return a Flux

Exceptions
pex::exceptions::InvalidParameterErrorif the exposure has no PSF.
pex::exceptions::RangeErrorif the warping (centering) kernel is not fully contained within the exposure.
pex::exceptions::RangeErrorif the center not within exposure. (This avoids insane center values from confusing the test for warping kernel within exposure).

Implements lsst::meas::base::SingleFrameAlgorithm.

Definition at line 188 of file PeakLikelihoodFlux.cc.

189 {
190 // get the value from the centroid slot only
191 geom::Point2D center = _centroidExtractor(measRecord, _flagHandler);
192 FluxResult result;
194 MaskedImageT const &mimage = exposure.getMaskedImage();
195
206 if (!exposure.hasPsf()) {
207 throw LSST_EXCEPT(pex::exceptions::InvalidParameterError, "exposure has no PSF");
208 }
209 std::shared_ptr<afw::detection::Psf const> psfPtr = exposure.getPsf();
210 if (!geom::Box2D(mimage.getBBox()).contains(center)) {
212 os << "Center = " << center << " not in exposure bbox" << mimage.getBBox();
213 throw LSST_EXCEPT(pex::exceptions::RangeError, os.str());
214 }
215
216 // compute parent index and fractional offset of ctrPix: the pixel closest to "center",
217 // the centroid of the source. This assumes that the image's XY0 is (0, 0).
218 std::pair<int, double> const xCtrPixParentIndFrac = afw::image::positionToIndex(center.getX(), true);
219 std::pair<int, double> const yCtrPixParentIndFrac = afw::image::positionToIndex(center.getY(), true);
220
221 geom::Point2I ctrPixParentInd(xCtrPixParentIndFrac.first + mimage.getX0(),
222 yCtrPixParentIndFrac.first + mimage.getY0());
223 geom::Point2D ctrPixPos(afw::image::indexToPosition(ctrPixParentInd[0]),
224 afw::image::indexToPosition(ctrPixParentInd[1]));
225
226 // compute weight = 1/sum(PSF^2) for PSF at ctrPix, where PSF is normalized to a sum of 1
227 PsfAttributes psfAttr(psfPtr, ctrPixParentInd);
228 double weight = psfAttr.computeEffectiveArea();
229
230 /*
231 * Compute value of image at center of source, as shifted by a fractional pixel to center the source
232 * on ctrPix.
233 */
234 MaskedImageT::SinglePixel mimageCtrPix = computeShiftedValue(
235 mimage, _ctrl.warpingKernelName,
236 geom::Point2D(xCtrPixParentIndFrac.second, yCtrPixParentIndFrac.second), ctrPixParentInd);
237 double instFlux = mimageCtrPix.image() * weight;
238 double var = mimageCtrPix.variance() * weight * weight;
239 result.instFlux = instFlux;
240 result.instFluxErr = std::sqrt(var);
241 measRecord.set(_instFluxResultKey, result);
242 _flagHandler.setValue(measRecord, FAILURE.number, false);
243}
#define LSST_EXCEPT(type,...)
Create an exception with a given type.
Definition Exception.h:48
std::ostream * os
Definition Schema.cc:557
MaskedImage< ImageT, MaskT, VarianceT > MaskedImageT
Definition Exposure.h:74
A floating-point coordinate rectangle geometry.
Definition Box.h:413
bool contains(Point2D const &point) const noexcept
Return true if the box contains the point.
Definition Box.cc:322
void setValue(afw::table::BaseRecord &record, std::size_t i, bool value) const
Set the flag field corresponding to the given flag index.
std::string warpingKernelName
"Name of warping kernel (e.g. \"lanczos4\") used to compute the peak" ;
double indexToPosition(double ind)
Convert image index to image position.
Definition ImageUtils.h:55
int positionToIndex(double pos)
Convert image position to nearest integer index.
Definition ImageUtils.h:69
afw::image::MaskedImage< T >::SinglePixel computeShiftedValue(afw::image::MaskedImage< T > const &maskedImage, std::string const &warpingKernelName, geom::Point2D const &fracShift, geom::Point2I const &parentInd)
Compute the value of one pixel of an image after a fractional pixel shift Since we only want the valu...
T sqrt(T... args)
afw::table::Key< double > weight

◆ measureForced()

void lsst::meas::base::SimpleAlgorithm::measureForced ( afw::table::SourceRecord & measRecord,
afw::image::Exposure< float > const & exposure,
afw::table::SourceRecord const & refRecord,
afw::geom::SkyWcs const & refWcs ) const
inlineoverridevirtualinherited

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.

Implements lsst::meas::base::ForcedAlgorithm.

Reimplemented in lsst::meas::extensions::photometryKron::KronFluxAlgorithm.

Definition at line 172 of file Algorithm.h.

175 {
176 measure(measRecord, exposure);
177 }
virtual void measure(afw::table::SourceRecord &measRecord, afw::image::Exposure< float > const &exposure) const =0
Called to measure a single child source in an image.

◆ measureN()

void lsst::meas::base::SingleFrameAlgorithm::measureN ( afw::table::SourceCatalog const & measCat,
afw::image::Exposure< float > const & exposure ) const
virtualinherited

Called to simultaneously measure all children in a deblend family, in a single image.

Outputs should be saved in the given SourceCatalog, which can also be used to obtain centroid (see SafeCentroidExtractor) and shape (see SafeShapeExtractor) information.

The default implementation simply throws an exception, indicating that simultaneous measurement is not supported.

Definition at line 31 of file Algorithm.cc.

32 {
33 throw LSST_EXCEPT(pex::exceptions::LogicError, "measureN not implemented for this algorithm");
34}

◆ measureNForced()

void lsst::meas::base::SimpleAlgorithm::measureNForced ( afw::table::SourceCatalog const & measCat,
afw::image::Exposure< float > const & exposure,
afw::table::SourceCatalog const & refRecord,
afw::geom::SkyWcs const & refWcs ) const
inlineoverridevirtualinherited

Called to simultaneously measure all children in a deblend family, in a single image.

Outputs should be saved in the given SourceCatalog, which can also be used to obtain centroid (see SafeCentroidExtractor) and shape (see SafeShapeExtractor) information.

The default implementation simply throws an exception, indicating that simultaneous measurement is not supported.

Reimplemented from lsst::meas::base::ForcedAlgorithm.

Definition at line 179 of file Algorithm.h.

182 {
183 measureN(measCat, exposure);
184 }
virtual void measureN(afw::table::SourceCatalog const &measCat, afw::image::Exposure< float > const &exposure) const
Called to simultaneously measure all children in a deblend family, in a single image.
Definition Algorithm.cc:31

Member Data Documentation

◆ _logName

std::string lsst::meas::base::BaseAlgorithm::_logName
protectedinherited

Definition at line 69 of file Algorithm.h.

◆ FAILURE

FlagDefinition const lsst::meas::base::PeakLikelihoodFluxAlgorithm::FAILURE = flagDefinitions.addFailureFlag()
static

Definition at line 75 of file PeakLikelihoodFlux.h.


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