A class that calculates a centroid by fitting a circular Gaussian to the image. More...

#include <GaussianCentroid.h>

Inheritance diagram for lsst::meas::base::GaussianCentroidAlgorithm:

Public Types
enum	{ FAILURE =FlagHandler::FAILURE, NO_PEAK, N_FLAGS }
	Flag bits to be used with the 'flags' data member of the Result object. More...

typedef GaussianCentroidControl	Control

Public Member Functions
	GaussianCentroidAlgorithm (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

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

Public Member Functions inherited from lsst::meas::base::SimpleAlgorithm
virtual void	measureForced (afw::table::SourceRecord &measRecord, afw::image::Exposure< float > const &exposure, afw::table::SourceRecord const &refRecord, afw::image::Wcs const &refWcs) const

virtual void	measureNForced (afw::table::SourceCatalog const &measCat, afw::image::Exposure< float > const &exposure, afw::table::SourceCatalog const &refRecord, afw::image::Wcs const &refWcs) const

Public Member Functions inherited from lsst::meas::base::SingleFrameAlgorithm
virtual void	measureN (afw::table::SourceCatalog const &measCat, afw::image::Exposure< float > const &exposure) const

Public Member Functions inherited from lsst::meas::base::BaseAlgorithm
virtual	~BaseAlgorithm ()

Static Public Member Functions
template<typename PixelT >
static afw::geom::Point2D	fitCentroid (afw::image::Image< PixelT > const &im, double x0, double y0)
	x0, y0 is an initial guess for position, column More...

Private Attributes
Control	_ctrl

CentroidResultKey	_centroidKey

FlagHandler	_flagHandler

SafeCentroidExtractor	_centroidExtractor

Detailed Description

A class that calculates a centroid by fitting a circular Gaussian to the image.

Definition at line 82 of file GaussianCentroid.h.

Member Typedef Documentation

typedef GaussianCentroidControl lsst::meas::base::GaussianCentroidAlgorithm::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 98 of file GaussianCentroid.h.

Member Enumeration Documentation

anonymous enum

Flag bits to be used with the 'flags' data member of the Result object.

Inspect getFlagDefinitions() for more detailed explanations of each flag.

Enumerator
FAILURE
NO_PEAK
N_FLAGS

Definition at line 90 of file GaussianCentroid.h.

          {
         FAILURE=FlagHandler::FAILURE,
         NO_PEAK,
         N_FLAGS
     };

Constructor & Destructor Documentation

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

Definition at line 512 of file GaussianCentroid.cc.

   : _ctrl(ctrl),
     _centroidKey(
         CentroidResultKey::addFields(schema, name, "centroid from Gaussian Centroid algorithm", NO_UNCERTAINTY)
     ),
     _centroidExtractor(schema, name, true)
 {
     _flagHandler = FlagHandler::addFields(schema, name,
                                           getFlagDefinitions().begin(), getFlagDefinitions().end());
 }

Member Function Documentation

void lsst::meas::base::GaussianCentroidAlgorithm::fail	(	afw::table::SourceRecord &	measRecord,
		MeasurementError *	error = `NULL`
	)		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 573 of file GaussianCentroid.cc.

                                                                                                       {
     _flagHandler.handleFailure(measRecord, error);
 }

template<typename PixelT >

template afw::geom::Point2D lsst::meas::base::GaussianCentroidAlgorithm::fitCentroid	(	afw::image::Image< PixelT > const &	im,
		double	x0,
		double	y0
	)

static

x0, y0 is an initial guess for position, column

Compute centroids with 2-D Gaussian fitter

Definition at line 528 of file GaussianCentroid.cc.

   {
     base::FittedModel fit = base::twodg(image, x, y);
     double const xCen = fit.params[base::FittedModel::X0];
     double const yCen = fit.params[base::FittedModel::Y0];
     return afw::geom::Point2D(xCen, yCen);
 }

void lsst::meas::base::GaussianCentroidAlgorithm::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.

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

Definition at line 539 of file GaussianCentroid.cc.

         {
     // get our current best guess about the centroid: either a centroider measurement or peak.
     afw::geom::Point2D center = _centroidExtractor(measRecord, _flagHandler);
     CentroidResult result;
     result.x = center.getX();
     result.y = center.getY();
     measRecord.set(_centroidKey, result); // better than NaN
     typedef afw::image::Image<float> ImageT;
     ImageT const& image = *exposure.getMaskedImage().getImage();
 
     int x = static_cast<int>(center.getX() + 0.5);
     int y = static_cast<int>(center.getY() + 0.5);
 
     x -= image.getX0();                 // work in image Pixel coordinates
     y -= image.getY0();
 
     FittedModel fit = twodg(image, x, y); // here's the fitter
     if (fit.params[FittedModel::PEAK] <= 0) {
         throw LSST_EXCEPT(
             MeasurementError,
             _flagHandler.getDefinition(NO_PEAK).doc,
             NO_PEAK
         );
     }
     result.x = lsst::afw::image::indexToPosition(image.getX0()) + fit.params[FittedModel::X0];
     result.y = lsst::afw::image::indexToPosition(image.getY0()) + fit.params[FittedModel::Y0];
     _flagHandler.setValue(measRecord, FAILURE, false);  // if we had a suspect flag, we'd set that instead
     measRecord.set(_centroidKey, result);
 }

Member Data Documentation

SafeCentroidExtractor lsst::meas::base::GaussianCentroidAlgorithm::_centroidExtractor

private

Definition at line 127 of file GaussianCentroid.h.

CentroidResultKey lsst::meas::base::GaussianCentroidAlgorithm::_centroidKey

private

Definition at line 125 of file GaussianCentroid.h.

Control lsst::meas::base::GaussianCentroidAlgorithm::_ctrl

private

Definition at line 124 of file GaussianCentroid.h.

FlagHandler lsst::meas::base::GaussianCentroidAlgorithm::_flagHandler

private

Definition at line 126 of file GaussianCentroid.h.

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

/home/lsstsw/stack/Linux64/meas_base/11.0+1/include/lsst/meas/base/GaussianCentroid.h
/home/lsstsw/stack/Linux64/meas_base/11.0+1/src/GaussianCentroid.cc

Public Types

Public Member Functions

Static Public Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation