PointSourceDetector Class Reference

Public Types

enum optimizerStrategy { dontOptimize = 1, optimizeForSigma, optimizeForChi2 }

Public Member Functions

PointSourceDetector (const DitherEnvironment &DE)
void detect ()

Protected Member Functions

SignificanceMap computeSignificanceMap () const
void optimizeSegments (list< ImSegment > &segments, const optimizerStrategy opt)
PointSource optimizeModelOnGrid (const ImSegment &s, std::ostream &out, const optimizerStrategy opt)
PointSource optimizeModelWithSimplex (const ImSegment &s, std::ostream &out, const optimizerStrategy opt)
void placePointSourceModels (void)
PointSource generatePointSource (const float source_x, const float source_y, const float source_l) const
MArray< float, 2 > make_image (const PointSource &data) const
void make_image_header (const PointSource &data, FitsHeader &h) const
void writeCutout (const PointSource &best_PointSource, const int id) const
bool consider_res_elem (const ResElem &res) const
bool detection_criteria (const PointSource &data) const
float get_normflux (float value, int x, int y) const
return the normalized flux given a photon count value in pixel x and y
void normalize_model (PointSource &data) const
void compute_chi2 (PointSource &data) const
void compute_chi2_stacked (PointSource &data) const
void compute_sigma (PointSource &data) const
void compute_probabilities (PointSource &data) const
void equivalent_width (PointSource &data) const
void photometry (PointSource &data) const
int count_res_elems (const PointSource &data) const
void log_detection (std::ostream &out, const int sid, const PointSource &ps)
void log_photometry (std::ostream &out, const int sid, const PointSource &ps)
float back_to_flambda (const float photcount, const float tint, const float lam)
void log_outflux (std::ostream &out, const float pxx, const float pyy, const float photcount, const float photdcount, const float photflux, const float photdflux)
optimizerStrategy get_optimizer_strategy (const DetectOptions &g)

Protected Attributes

const DitherEnvironment & DE_
the DetectionEnvironment
const DetectOptions & detect_pars_
detect command line parameters and options
const ProjectorSet & P_
the DE's ProjectorSet
const vector< VFrame > & vframes_
vector of data vframes of one dither set
int nline_

Friends

class OptimizePointSource

Detailed Description

Bayesian detection of point-like sources in sets of dithered frames.

First, construct a SignificanceMap assuming a point-like source on a grid in x,y,wavelength on sky. Use ProjectorSet to obtain the resolution elements on the CCDs in the dither set that are affected and compute their significance.

Then, segment the SignificanceMap using an ImSegmenter. For the segments with point-like morphology, go ahead and construct a full model of a point-like source and compare against the data in a chi2-sense.

Member Enumeration Documentation

enum PointSourceDetector::optimizerStrategy

When finding the optimal point source parameters for each segment, this value determines which strategy will be used.

Enumerator:

dontOptimize
optimizeForSigma
optimizeForChi2

Constructor & Destructor Documentation

PointSourceDetector::PointSourceDetector ( const DitherEnvironment & DE ) [inline]

Member Function Documentation

void PointSourceDetector::detect ( )

Run the detection process for point sources: Compute the significance map, segment it, and compare the segments against point source models. Output catalog and cutout images.

References computeSignificanceMap(), DE_, DetectOptions::dump_segments, ImageSegmenter::expand(), DetectOptions::expand_sigma, g, DitherEnvironment::get_detect_parameters(), get_optimizer_strategy(), optimizeSegments(), placePointSourceModels(), DetectOptions::read_psigma, ImageSegmenter::segment(), DetectOptions::sigma, DetectOptions::xdetect_file, and DetectOptions::xdetect_size.

Referenced by main().

SignificanceMap PointSourceDetector::computeSignificanceMap ( ) const [protected]

Compute the significance map for a set of dithes by testing for the presence of a point source on coarse grid on sky and wavelength. The significance map contains the significance for a detection above the null-hypothesis that there's nothing there. Only the total amount of flux is tested, not the compatibility with a point source on sky or the CCD.

Compute the significance map for a set of dithes by testing for the presence of a point source on coarse grid on sky and wavelength. The significance map contains the significance for a detection above the null-hypothesis that there's nothing there. Only the total amount of flux is tested (the compatibility with point source on-sky), not the compatibility with a point source on the CCD. The latter is done in optimizeForChi2().

References PointSource::DetectionData::ap_sigma, DetectOptions::aperture, SignificanceMap::clear(), compute_sigma(), PointSource::dd, DE_, PointSource::debug_reselem_list(), DetectOptions::dump_segments, DetectOptions::dump_sigma, ProjectorSet::findResElemsForPointSourceInAperture(), g, DitherEnvironment::get_detect_parameters(), DitherEnvironment::get_grid_limits(), DitherEnvironment::get_output_basename(), DitherEnvironment::get_projector_set(), SkySampleLimits::index_to_l(), SkySampleLimits::index_to_x(), SkySampleLimits::index_to_y(), PointSource::DetectionData::l, SkySampleLimits::lmax, SkySampleLimits::lmin, SkySampleLimits::lstep, SkySampleLimits::nlstep, SkySampleLimits::nxstep, SkySampleLimits::nystep, P, DetectOptions::psf_size, SignificanceMap::set_sigma(), DetectOptions::sigma, SignificanceMap::write_significance_map(), SkySampleLimits::x_to_index(), DetectOptions::xdetect_file, SkySampleLimits::xmax, SkySampleLimits::xmin, PointSource::DetectionData::xs, SkySampleLimits::xstep, SkySampleLimits::ymax, SkySampleLimits::ymin, PointSource::DetectionData::ys, and SkySampleLimits::ystep.

Referenced by detect().

void PointSourceDetector::optimizeSegments	(	list< ImSegment > &	segments,
		const optimizerStrategy	opt
	)			`[protected]`

Iterate over a segment list and for each segment, find the optimal point-source position and wavelength by comparing a full point-source model to the pixel fluxes making up the ResElems in the ImSegment.

References back_to_flambda(), DE_, detection_criteria(), dontOptimize, ImSegment::evalgood(), SkySampleLimits::findex_to_l(), SkySampleLimits::findex_to_x(), SkySampleLimits::findex_to_y(), ImSegment::fwhmzz_, g, generatePointSource(), DitherEnvironment::get_detect_parameters(), DitherEnvironment::get_grid_limits(), DitherEnvironment::get_output_basename(), ImSegment::icx_, ImSegment::icy_, ImSegment::icz_, ImSegment::id_, SkySampleLimits::lmin, log_detection(), log_outflux(), log_photometry(), SkySampleLimits::lstep, SkySampleLimits::lstep_fine, optimizeModelOnGrid(), optimizeModelWithSimplex(), photometry(), DitherEnvironment::write_cmd_line(), writeCutout(), and SkySampleLimits::xstep_fine.

Referenced by detect().

PointSource PointSourceDetector::optimizeModelOnGrid	(	const ImSegment &	s,
		std::ostream &	out,
		const optimizerStrategy	opt
	)			`[protected]`

Find the optimal point-source model for a given ImSegment by finding the optimal chi2 or Sigma on a fine grid in the neighborhood of the maximum intensity of the ImSegment

References PointSource::DetectionData::ap_sigma, PointSource::DetectionData::chi2_w, PointSource::DetectionData::dataflux, PointSource::dd, DE_, DetectOptions::dump_laes, DetectOptions::fwhm_sample_radius, ImSegment::fwhmxy_, ImSegment::fwhmzz_, g, generatePointSource(), DitherEnvironment::get_detect_parameters(), DitherEnvironment::get_grid_limits(), ImSegment::icx_, ImSegment::icy_, ImSegment::icz_, ImSegment::id_, SkySampleLimits::lmin, log_detection(), SkySampleLimits::lstep, SkySampleLimits::lstep_fine, PointSource::DetectionData::modflux, nline_, optimizeForSigma, DetectOptions::sigma, SkySampleLimits::xmin, SkySampleLimits::xstep, SkySampleLimits::xstep_fine, SkySampleLimits::ymin, and SkySampleLimits::ystep.

Referenced by optimizeSegments().

PointSource PointSourceDetector::optimizeModelWithSimplex	(	const ImSegment &	s,
		std::ostream &	out,
		const optimizerStrategy	opt
	)			`[protected]`

Find the optimal point-source model for a given ImSegment by simplex minimization of chi2 or Sigma in the neighborhood of the maximum intensity of the ImSegment

References a, DE_, SkySampleLimits::findex_to_l(), SkySampleLimits::findex_to_x(), SkySampleLimits::findex_to_y(), ImSegment::fwhmxy_, ImSegment::fwhmzz_, generatePointSource(), DitherEnvironment::get_grid_limits(), ImSegment::icx_, ImSegment::icy_, ImSegment::icz_, Amoeba< Func >::initialize_y(), SkySampleLimits::lstep, nline_, Amoeba< Func >::optimize(), OptimizePointSource, SkySampleLimits::xstep, and SkySampleLimits::ystep.

Referenced by optimizeSegments().

void PointSourceDetector::placePointSourceModels ( void ) [protected]

Calculate chi2 for point-source models at a list of {x,y,lambda} on sky. No optimization is carried out. The list of positions are read from the cross-detection file.

Calculate chi2 for a point-source model at a list of {x,y,lambda} on sky. No optimization is carried out. The list of positions are read from the cross-detection file.

References DE_, g, generatePointSource(), DitherEnvironment::get_detect_parameters(), log_detection(), log_photometry(), nline_, DetectOptions::outputname, photometry(), DetectOptions::simsrc, DitherEnvironment::write_cmd_line(), DetectOptions::write_cutouts, writeCutout(), and DetectOptions::xdetect_file.

Referenced by detect().

PointSource PointSourceDetector::generatePointSource	(	const float	source_x,
		const float	source_y,
		const float	source_l
	)			const `[protected]`

Fill in a struct LAE with the full point-source model at sky position {x,y,lambda} and compute the chi2 for that model.

Fill in a struct PointSource with the full point-source model at sky position {x,y,lambda} and compute the chi2 for that model.

References DetectOptions::aperture, compute_chi2(), compute_chi2_stacked(), compute_probabilities(), compute_sigma(), PointSource::dd, DE_, equivalent_width(), ProjectorSet::fillInPointSourceModel(), ProjectorSet::findResElemsForPointSourceInAperture(), DitherEnvironment::get_detect_parameters(), DitherEnvironment::get_projector_set(), PointSource::DetectionData::l, normalize_model(), P, PointSource::PointSourceModel, DetectOptions::psf_size, PointSource::DetectionData::xs, and PointSource::DetectionData::ys.

Referenced by optimizeModelOnGrid(), optimizeModelWithSimplex(), optimizeSegments(), and placePointSourceModels().

MArray< float, 2 > PointSourceDetector::make_image ( const PointSource & data ) const [protected]

Create an Image of all fibers exceeding g.flux_thresh drawing the model image, the data and the errors. px and py are the size of the PSF in pixels.

Create an Image of all fibers exceeding detect_pars_.flux_thresh drawing the model image, the data and the errors. px and py are the size of the PSF in pixels.

References PooledList< T >::begin(), consider_res_elem(), count_res_elems(), PointSource::dd, DE_, PooledList< T >::end(), PointSource::DetectionData::fdat_fmod, Pixel::flux, VFrame::get_distortion(), VFrame::get_fibermodel(), FiberModel::get_single_fiberflux(), DitherEnvironment::get_vframe(), ResElem::npix(), ResElem::p, PointSource::PointSourceModel, PointSource::px, PointSource::py, ResElem::tu, vframes_, Pixel::x, ResElem::x, Pixel::y, and ResElem::y.

Referenced by writeCutout().

void PointSourceDetector::make_image_header	(	const PointSource &	data,
		FitsHeader &	h
	)			const `[protected]`

Referenced by writeCutout().

void PointSourceDetector::writeCutout	(	const PointSource &	best_PointSource,
		const int	id
	)			const `[protected]`

References PointSource::DetectionData::ap_sigma, PointSource::DetectionData::chi2, PointSource::DetectionData::chi2_s, PointSource::DetectionData::chi2_w, PointSource::DetectionData::cont, PointSource::dd, DE_, PointSource::DetectionData::eqw, DitherEnvironment::get_output_basename(), PointSource::DetectionData::l, make_image(), make_image_header(), PointSource::DetectionData::modflux, DitherEnvironment::write_cmd_line(), PointSource::DetectionData::xs, and PointSource::DetectionData::ys.

Referenced by optimizeSegments(), and placePointSourceModels().

bool PointSourceDetector::consider_res_elem ( const ResElem & res ) const [inline, protected]

check the properties of a resolution element to see if it should be dropped or included in the calculation of sigma, chi2, ...

References ResElem::apfrac, detect_pars_, DetectOptions::flux_thresh, and ResElem::ignore.

Referenced by compute_chi2(), compute_chi2_stacked(), compute_sigma(), count_res_elems(), equivalent_width(), make_image(), make_image_header(), normalize_model(), and photometry().

bool PointSourceDetector::detection_criteria ( const PointSource & data ) const [protected]

Check if a significant detection passes some criteria making it a good PointSource candidate

References PointSource::DetectionData::ap_sigma, DetectOptions::chi, PointSource::DetectionData::chi2, PointSource::DetectionData::chi2_w, DetectOptions::chi_w, PointSource::dd, detect_pars_, DetectOptions::eqw, PointSource::DetectionData::eqw, DetectOptions::flux, PointSource::DetectionData::modflux, and DetectOptions::sigma.

Referenced by optimizeSegments().

float PointSourceDetector::get_normflux	(	float	value,
		int	x,
		int	y
	)			const `[protected]`

Referenced by compute_chi2().

void PointSourceDetector::normalize_model ( PointSource & data ) const [protected]

compute best-fit normalization of model to data, also calculate and update total measured flux and its error in the ResElems

References PooledList< T >::begin(), consider_res_elem(), PointSource::dd, ResElem::dflux, ResElem::dfluxe, PooledList< T >::end(), ResElem::f, PointSource::DetectionData::fdat_fmod, Pixel::flux, ProjectorSet::get_fiber_x(), ProjectorSet::get_fiber_y(), ResElem::npix(), ResElem::p, P_, PointSource::PointSourceModel, ResElem::tu, vframes_, Pixel::x, ResElem::xsky, Pixel::y, and ResElem::ysky.

Referenced by generatePointSource().

void PointSourceDetector::compute_chi2 ( PointSource & data ) const [protected]

compute best fit chisquare and flux value of tested PointSource Input:

PointSource data structure Output: modifies PointSource structure
total flux of PointSource on the chip in ADU from data: PointSource.dataflux
best fit total flux of PointSource on the chip in ADU from model: PointSource.modflux
fraction of flux on the sky which is on the chip: PointSource.fluxfrac
degrees of freedom used to calculate chi^2: PointSource.deg_f
reduced chi^2 of best-fitting model: PointSource.chi2

References ResElem::apfrac, PooledList< T >::begin(), PointSource::DetectionData::chi2, PointSource::DetectionData::chi2_w, consider_res_elem(), PointSource::DetectionData::dataflux, PointSource::dd, PointSource::DetectionData::deg_f, ResElem::dflux, ResElem::dfluxe, PooledList< T >::end(), ResElem::ext, PointSource::DetectionData::fdat_fmod, Pixel::flux, PointSource::DetectionData::fluxfrac, get_normflux(), ResElem::mflux, PointSource::DetectionData::modflux, ResElem::npix(), ResElem::p, PointSource::PointSourceModel, ResElem::tu, vframes_, Pixel::x, and Pixel::y.

Referenced by generatePointSource().

void PointSourceDetector::compute_chi2_stacked ( PointSource & data ) const [protected]

compute best fit chisquare and flux value of tested PointSource using a stacked image Input:

PointSource data structure Output: modifies PointSource structure
degrees of freedom used to calculate chi^2: PointSource.deg_f_s
reduced chi^2 of best-fitting model: PointSource.chi2_s

References ResElem::apfrac, PooledList< T >::begin(), PointSource::DetectionData::chi2_s, consider_res_elem(), PointSource::dd, PointSource::DetectionData::deg_f_s, PooledList< T >::end(), PointSource::DetectionData::fdat_fmod, Pixel::flux, ResElem::npix(), ResElem::p, PointSource::PointSourceModel, PointSource::px, PointSource::py, ResElem::tu, vframes_, Pixel::x, ResElem::x, Pixel::y, and ResElem::y.

Referenced by generatePointSource().

void PointSourceDetector::compute_sigma ( PointSource & data ) const [protected]

compute significance of detection of tested PointSource also set ignore flag in res elements that have continuum detections Input:

PointSource data structure Output: Modifies PointSource structure
significance of detection: PointSource.sigma
left and right continuum values

compute significance of detection at a given location on the sky (and wavelength).

Input:

PointSource data structure Output: Modifies PointSource structure
significance of detection: PointSource.sigma
left and right continuum values

This is a hot-spot in the detection code. Performance needs to be monitored/improved.

References PointSource::DetectionData::ap_sigma, ResElem::apfrac, PooledList< T >::begin(), consider_res_elem(), PointSource::DetectionData::cont, ResElem::cont, PointSource::DetectionData::dcont, PointSource::dd, PooledList< T >::end(), PointSource::DetectionData::fb_sigma, ResElem::npix(), ResElem::p, PointSource::PointSourceModel, ResElem::tf, ResElem::tu, vframes_, ResElem::x, Pixel::x, and Pixel::y.

Referenced by computeSignificanceMap(), and generatePointSource().

void PointSourceDetector::compute_probabilities ( PointSource & data ) const [protected]

compute probabilities also set ignore flag in res elements that have continuum detections Input:

PointSource data structure Output: Modifies PointSource structure
probability for individual fit: PointSource.gammq
probability for stacked image fit: PointSource.gammq_s

References PointSource::DetectionData::chi2, PointSource::DetectionData::chi2_s, PointSource::dd, PointSource::DetectionData::deg_f, PointSource::DetectionData::deg_f_s, gammq(), PointSource::DetectionData::gammq, and PointSource::DetectionData::gammq_s.

Referenced by generatePointSource().

void PointSourceDetector::equivalent_width ( PointSource & data ) const [protected]

compute the equivalent width Input:

PointSource data structure Output: modifies PointSource structure
calculates the equivalent width

compute the equivalent width Input:

PointSource data structure Output: modifies PointSource structure
calculates the equivalent width
calculates a continuum estimate

References ResElem::apfrac, PooledList< T >::begin(), c, consider_res_elem(), PointSource::DetectionData::cont, PointSource::dd, DE_, PooledList< T >::end(), PointSource::DetectionData::eqw, ResElem::ext, VFrame::get_cont(), VFrame::get_distortion(), Projector::get_vframe(), DitherEnvironment::get_vframe(), Distortion::get_wavelength_boundaries(), ProjectorSet::getProjector(), ResElem::mflux, ResElem::npix(), ResElem::p, P_, PointSource::PointSourceModel, ResElem::tf, ResElem::tu, vframes_, Pixel::x, ResElem::x, Pixel::y, and ResElem::y.

Referenced by generatePointSource().

void PointSourceDetector::photometry ( PointSource & data ) const [protected]

do photometry on a detected point source detection

Input:

PointSource data structure Output: Modifies PointSource structure
light center of detection: PointSource.x, PointSource.y

Note: Contrary to the name this routine currently only calculates the light center

perform weighted aperture photometry on a detected point source

Input:

PointSource data structure Output: Modifies PointSource structure
light center of detection: PointSource.x, PointSource.y

References ResElem::apfrac, PooledList< T >::begin(), consider_res_elem(), PointSource::dd, DE_, PointSource::PhotometryData::dwflux, PooledList< T >::end(), PointSource::DetectionData::fluxfrac, PointSource::PhotometryData::fluxfrac, VFrame::get_cont(), DitherEnvironment::get_fluxnorm(), DitherEnvironment::get_vframe(), PointSource::PhotometryData::l, ResElem::l, ResElem::npix(), ResElem::p, PointSource::pd, PointSource::PointSourceModel, ResElem::tf, ResElem::tu, vframes_, PointSource::PhotometryData::wflux, PointSource::PhotometryData::x, ResElem::x, Pixel::x, ResElem::xsky, PointSource::PhotometryData::y, Pixel::y, and ResElem::ysky.

Referenced by optimizeSegments(), and placePointSourceModels().

int PointSourceDetector::count_res_elems ( const PointSource & data ) const [protected]

count the resolution elements in a PointSource

References PooledList< T >::begin(), consider_res_elem(), PooledList< T >::end(), and PointSource::PointSourceModel.

Referenced by make_image().

void PointSourceDetector::log_detection	(	std::ostream &	out,
		const int	sid,
		const PointSource &	ps
	)			`[protected]`

Write data for the current model canididate to a log file (the .det file)

Write data for the current model candidate to a log file (the detect_line.dat file)

References PointSource::dd, and nline_.

Referenced by optimizeModelOnGrid(), optimizeSegments(), and placePointSourceModels().

void PointSourceDetector::log_photometry	(	std::ostream &	out,
		const int	sid,
		const PointSource &	ps
	)			`[protected]`

Write photometry for the current model candidate to a detect_phot.dat file

References PointSource::pd.

Referenced by optimizeSegments(), and placePointSourceModels().

float PointSourceDetector::back_to_flambda	(	const float	photcount,
		const float	tint,
		const float	lam
	)			`[protected]`

References c.

Referenced by optimizeSegments().

void PointSourceDetector::log_outflux	(	std::ostream &	out,
		const float	pxx,
		const float	pyy,
		const float	photcount,
		const float	photdcount,
		const float	photflux,
		const float	photdflux
	)			`[protected]`

Referenced by optimizeSegments().

PointSourceDetector::optimizerStrategy PointSourceDetector::get_optimizer_strategy ( const DetectOptions & g ) [protected]

References dontOptimize, DetectOptions::optimize, optimizeForChi2, and optimizeForSigma.

Referenced by detect().

Friends And Related Function Documentation

friend class OptimizePointSource [friend]

Referenced by optimizeModelWithSimplex().

Field Documentation

const DitherEnvironment& PointSourceDetector::DE_ [protected]

Referenced by computeSignificanceMap(), detect(), equivalent_width(), generatePointSource(), make_image(), make_image_header(), optimizeModelOnGrid(), optimizeModelWithSimplex(), optimizeSegments(), photometry(), placePointSourceModels(), and writeCutout().

const DetectOptions& PointSourceDetector::detect_pars_ [protected]

Referenced by consider_res_elem(), detection_criteria(), and make_image_header().

const ProjectorSet& PointSourceDetector::P_ [protected]

Referenced by equivalent_width(), make_image_header(), and normalize_model().

const vector<VFrame >& PointSourceDetector::vframes_ [protected]

Referenced by compute_chi2(), compute_chi2_stacked(), compute_sigma(), equivalent_width(), make_image(), normalize_model(), and photometry().

int PointSourceDetector::nline_ [protected]

Referenced by log_detection(), optimizeModelOnGrid(), optimizeModelWithSimplex(), and placePointSourceModels().