lsst::jointcal::ConstrainedAstrometryModel Class Reference

A multi-component model, fitting mappings for sensors and visits simultaneously. More...

#include <ConstrainedAstrometryModel.h>

Inheritance diagram for lsst::jointcal::ConstrainedAstrometryModel:

Public Member Functions
	ConstrainedAstrometryModel (CcdImageList const &ccdImageList, std::shared_ptr< ProjectionHandler const > projectionHandler, int chipOrder, int visitOrder)
	ConstrainedAstrometryModel (ConstrainedAstrometryModel const &)=delete
	No copy or move: there is only ever one instance of a given model (i.e. per ccd+visit)
	ConstrainedAstrometryModel (ConstrainedAstrometryModel &&)=delete
ConstrainedAstrometryModel &	operator= (ConstrainedAstrometryModel const &)=delete
ConstrainedAstrometryModel &	operator= (ConstrainedAstrometryModel &&)=delete
AstrometryMapping const *	getMapping (CcdImage const &) const override
	Mapping associated to a given CcdImage.
Eigen::Index	assignIndices (std::string const &whatToFit, Eigen::Index firstIndex) override
	Positions the various parameter sets into the parameter vector, starting at firstIndex.
void	offsetParams (Eigen::VectorXd const &Delta) override
	Dispaches the offsets after a fit step into the actual locations of parameters.
void	freezeErrorTransform () override
	From there on, measurement errors are propagated using the current transforms (and no longer evolve).
std::size_t	getTotalParameters () const override
	Return the total number of parameters in this model.
AstrometryTransform const &	getChipTransform (CcdIdType chip) const
	Access to mappings.
AstrometryTransform const &	getVisitTransform (VisitIdType const &visit) const
	Access to mappings.
std::vector< VisitIdType >	getVisits () const
	Access to array of visits involved in the solution.
const std::shared_ptr< AstrometryTransform const >	getSkyToTangentPlane (CcdImage const &ccdImage) const override
	The mapping of sky coordinates (i.e.
std::shared_ptr< afw::geom::SkyWcs >	makeSkyWcs (CcdImage const &ccdImage) const override
	Make a SkyWcs that contains this model.
void	print (std::ostream &out) const override
	Print a string representation of the contents of this mapping, for debugging.
std::size_t	getNpar (CcdImage const &ccdImage) const
	Return the number of parameters in the mapping of CcdImage.
bool	validate (CcdImageList const &ccdImageList, int ndof) const
	Return true if this is a "reasonable" model.

Protected Attributes
LOG_LOGGER	_log
	lsst.logging instance, to be created by a subclass so that messages have consistent name.

Private Member Functions
AstrometryMapping *	findMapping (CcdImage const &ccdImage) const override
	Return a pointer to the mapping associated with this ccdImage.

Detailed Description

A multi-component model, fitting mappings for sensors and visits simultaneously.

This is the model used to fit mappings as the combination of a transformation depending on the chip number (instrument model) and a transformation per visit (anamorphism). The two-transformation Mapping required for this model is ChipVisitAstrometryMapping. This modeling of distortions is meant for a set of images from a single mosaic imager.

Parameters

ccdImageList	The exposures that will be fit.
projectionHandler	The projection from "Sky" (where the "true" coordinates live) to "Tangent Plane" (where the fitting occurs).
chipOrder	The polynomial order of the pixel->focal plane mapping for each sensor.
visitOrder	The polynomial order of the focal plane->tangent plane mapping for each visit.

Definition at line 62 of file ConstrainedAstrometryModel.h.

Constructor & Destructor Documentation

ConstrainedAstrometryModel() [1/3]

lsst::jointcal::ConstrainedAstrometryModel::ConstrainedAstrometryModel	(	CcdImageList const &	ccdImageList,
		std::shared_ptr< ProjectionHandler const >	projectionHandler,
		int	chipOrder,
		int	visitOrder )

Definition at line 65 of file ConstrainedAstrometryModel.cc.

        : AstrometryModel(LOG_GET("lsst.jointcal.ConstrainedAstrometryModel")),
          _skyToTangentPlane(std::move(projectionHandler)) {
    // keep track of which chip we want to hold fixed (the one closest to the middle of the focal plane)
    double minRadius2 = std::numeric_limits<double>::infinity();
    CcdIdType constrainedChip = -1;
 
    // first loop to initialize all visit and chip transforms.
    for (auto &ccdImage : ccdImageList) {
        const CcdImage &im = *ccdImage;
        auto visit = im.getVisit();
        auto chip = im.getCcdId();
        auto visitp = _visitMap.find(visit);
        if (visitp == _visitMap.end()) {
            _visitMap[visit] = std::make_shared<SimplePolyMapping>(AstrometryTransformLinear(),
                                                                   AstrometryTransformPolynomial(visitOrder));
        }
        auto chipp = _chipMap.find(chip);
        if (chipp == _chipMap.end()) {
            auto center = ccdImage->getDetector()->getCenter(afw::cameraGeom::FOCAL_PLANE);
            double radius2 = std::pow(center.getX(), 2) + std::pow(center.getY(), 2);
            if (radius2 < minRadius2) {
                minRadius2 = radius2;
                constrainedChip = chip;
            }
 
            auto pixelsToFocal =
                    im.getDetector()->getTransform(afw::cameraGeom::PIXELS, afw::cameraGeom::FOCAL_PLANE);
            Frame const &frame = im.getImageFrame();
            // construct the chip transform by approximating the pixel->Focal afw::geom::Transform.
            AstrometryTransformPolynomial pol =
                    AstrometryTransformPolynomial(pixelsToFocal, frame, chipOrder);
            AstrometryTransformLinear shiftAndNormalize = normalizeCoordinatesTransform(frame);
            _chipMap[chip] = std::make_shared<SimplePolyMapping>(shiftAndNormalize,
                                                                 pol * shiftAndNormalize.inverted());
        }
    }
 
    // Hold the "central" chip map fixed and don't fit it, to remove a degeneracy.
    _chipMap.at(constrainedChip)->setToBeFit(false);
 
    // now, second loop to set the mappings of the CCdImages
    for (auto &ccdImage : ccdImageList) {
        const CcdImage &im = *ccdImage;
        auto visit = im.getVisit();
        auto chip = im.getCcdId();
 
        // check that the chip_indexed part was indeed assigned
        // (i.e. the reference visit was complete)
        if (_chipMap.find(chip) == _chipMap.end()) {
            LOGLS_WARN(_log, "Chip " << chip << " is missing in the reference exposure, expect troubles.");
            AstrometryTransformLinear norm = normalizeCoordinatesTransform(im.getImageFrame());
            _chipMap[chip] =
                    std::make_shared<SimplePolyMapping>(norm, AstrometryTransformPolynomial(chipOrder));
        }
        _mappings[ccdImage->getHashKey()] =
                std::make_unique<ChipVisitAstrometryMapping>(_chipMap[chip], _visitMap[visit]);
    }
    LOGLS_INFO(_log, "Got " << _chipMap.size() << " chip mappings and " << _visitMap.size()
                            << " visit mappings; holding chip " << constrainedChip << " fixed ("
                            << getTotalParameters() << " total parameters).");
    LOGLS_DEBUG(_log, "CcdImage map has " << _mappings.size() << " mappings, with "
                                          << _mappings.bucket_count() << " buckets and a load factor of "
                                          << _mappings.load_factor());
}

ConstrainedAstrometryModel() [2/3]

lsst::jointcal::ConstrainedAstrometryModel::ConstrainedAstrometryModel ( ConstrainedAstrometryModel const & )

delete

No copy or move: there is only ever one instance of a given model (i.e. per ccd+visit)

ConstrainedAstrometryModel() [3/3]

lsst::jointcal::ConstrainedAstrometryModel::ConstrainedAstrometryModel ( ConstrainedAstrometryModel && )

delete

Member Function Documentation

assignIndices()

Eigen::Index lsst::jointcal::ConstrainedAstrometryModel::assignIndices ( std::string const & whatToFit, Eigen::Index firstIndex )

overridevirtual

Positions the various parameter sets into the parameter vector, starting at firstIndex.

This routine decodes "DistortionsChip" and "DistortionsVisit" in whatToFit.

If whatToFit contains "Distortions" and not Distortions<Something>, it is understood as both chips and visits.

Implements lsst::jointcal::AstrometryModel.

Definition at line 141 of file ConstrainedAstrometryModel.cc.

                                                                              {
    Eigen::Index index = firstIndex;
    if (whatToFit.find("Distortions") == std::string::npos) {
        LOGLS_ERROR(_log, "assignIndices was called and Distortions is *not* in whatToFit");
        return 0;
    }
    // if we get here "Distortions" is in whatToFit
    _fittingChips = (whatToFit.find("DistortionsChip") != std::string::npos);
    _fittingVisits = (whatToFit.find("DistortionsVisit") != std::string::npos);
    // If nothing more than "Distortions" is specified, it means all:
    if ((!_fittingChips) && (!_fittingVisits)) {
        _fittingChips = _fittingVisits = true;
    }
    if (_fittingChips)
        for (auto &i : _chipMap) {
            i.second->setIndex(index);
            index += i.second->getNpar();
        }
    if (_fittingVisits)
        for (auto &i : _visitMap) {
            i.second->setIndex(index);
            index += i.second->getNpar();
        }
    // Tell the mappings which derivatives they will have to fill:
    for (auto &i : _mappings) {
        i.second->setWhatToFit(_fittingChips, _fittingVisits);
    }
    return index;
}

findMapping()

AstrometryMapping * lsst::jointcal::ConstrainedAstrometryModel::findMapping ( CcdImage const & ccdImage ) const

overrideprivatevirtual

Return a pointer to the mapping associated with this ccdImage.

Implements lsst::jointcal::AstrometryModel.

Definition at line 271 of file ConstrainedAstrometryModel.cc.

                                                                                         {
    auto i = _mappings.find(ccdImage.getHashKey());
    if (i == _mappings.end())
        throw LSST_EXCEPT(pex::exceptions::InvalidParameterError,
                          "ConstrainedAstrometryModel cannot find CcdImage " + ccdImage.getName());
    return i->second.get();
}

freezeErrorTransform()

void lsst::jointcal::ConstrainedAstrometryModel::freezeErrorTransform ( )

overridevirtual

From there on, measurement errors are propagated using the current transforms (and no longer evolve).

Implements lsst::jointcal::AstrometryModel.

Definition at line 185 of file ConstrainedAstrometryModel.cc.

                                                      {
    for (auto & i : _visitMap) i.second->freezeErrorTransform();
    for (auto & i : _chipMap) i.second->freezeErrorTransform();
}

getChipTransform()

const AstrometryTransform & lsst::jointcal::ConstrainedAstrometryModel::getChipTransform

(

CcdIdType

chip

)

const

Access to mappings.

Definition at line 190 of file ConstrainedAstrometryModel.cc.

                                                                                                  {
    auto chipp = _chipMap.find(chip);
    if (chipp == _chipMap.end()) {
        std::stringstream errMsg;
        errMsg << "No such chipId: " << chip << " among ";
        outputMapKeys(_chipMap, errMsg);
        std::cout << std::endl;
        throw pexExcept::InvalidParameterError(errMsg.str());
    }
    return chipp->second->getTransform();
}

getMapping()

const AstrometryMapping * lsst::jointcal::ConstrainedAstrometryModel::getMapping ( CcdImage const & ) const

overridevirtual

Mapping associated to a given CcdImage.

Implements lsst::jointcal::AstrometryModel.

Definition at line 133 of file ConstrainedAstrometryModel.cc.

                                                                                              {
    return findMapping(ccdImage);
}

getNpar()

std::size_t lsst::jointcal::AstrometryModel::getNpar ( CcdImage const & ccdImage ) const

inlineinherited

Return the number of parameters in the mapping of CcdImage.

Definition at line 56 of file AstrometryModel.h.

{ return findMapping(ccdImage)->getNpar(); }

getSkyToTangentPlane()

const std::shared_ptr< AstrometryTransform const > lsst::jointcal::ConstrainedAstrometryModel::getSkyToTangentPlane ( CcdImage const & ccdImage ) const

inlineoverridevirtual

The mapping of sky coordinates (i.e.

the coordinate system in which fitted stars are reported) onto the Tangent plane (into which the pixel coordinates are transformed).

Implements lsst::jointcal::AstrometryModel.

Definition at line 113 of file ConstrainedAstrometryModel.h.

                                                     {
        return _skyToTangentPlane->getSkyToTangentPlane(ccdImage);
    }

getTotalParameters()

std::size_t lsst::jointcal::ConstrainedAstrometryModel::getTotalParameters ( ) const

overridevirtual

Return the total number of parameters in this model.

Implements lsst::jointcal::AstrometryModel.

Definition at line 222 of file ConstrainedAstrometryModel.cc.

                                                               {
    std::size_t total = 0;
    for (auto &i : _chipMap) {
        total += i.second->getNpar();
    }
    for (auto &i : _visitMap) {
        total += i.second->getNpar();
    }
    return total;
}

getVisits()

std::vector< VisitIdType > lsst::jointcal::ConstrainedAstrometryModel::getVisits

(

)

const

Access to array of visits involved in the solution.

Definition at line 203 of file ConstrainedAstrometryModel.cc.

                                                                   {
    std::vector<VisitIdType> res;
    res.reserve(_visitMap.size());
    for (const auto & i : _visitMap) res.push_back(i.first);
    return res;
}

getVisitTransform()

const AstrometryTransform & lsst::jointcal::ConstrainedAstrometryModel::getVisitTransform

(

VisitIdType const &

visit

)

const

Access to mappings.

Definition at line 210 of file ConstrainedAstrometryModel.cc.

                                                                                                       {
    auto visitp = _visitMap.find(visit);
    if (visitp == _visitMap.end()) {
        std::stringstream errMsg;
        errMsg << "No such visitId: " << visit << " among ";
        outputMapKeys(_visitMap, errMsg);
        std::cout << std::endl;
        throw pexExcept::InvalidParameterError(errMsg.str());
    }
    return visitp->second->getTransform();
}

makeSkyWcs()

std::shared_ptr< afw::geom::SkyWcs > lsst::jointcal::ConstrainedAstrometryModel::makeSkyWcs ( CcdImage const & ccdImage ) const

overridevirtual

Make a SkyWcs that contains this model.

Parameters

ccdImage

The exposure to create the SkyWcs for.

Returns

SkyWcs containing this model.

Implements lsst::jointcal::AstrometryModel.

Definition at line 233 of file ConstrainedAstrometryModel.cc.

                                                                                                  {
    auto proj = std::dynamic_pointer_cast<const TanRaDecToPixel>(getSkyToTangentPlane(ccdImage));
    jointcal::Point tangentPoint(proj->getTangentPoint());
 
    auto imageFrame = ccdImage.getImageFrame();
    auto pixelsToFocal = getChipTransform(ccdImage.getCcdId()).toAstMap(imageFrame);
    jointcal::Frame focalBox = getChipTransform(ccdImage.getCcdId()).apply(imageFrame, false);
    auto focalToIwc = getVisitTransform(ccdImage.getVisit()).toAstMap(focalBox);
 
    ast::Frame pixelFrame(2, "Domain=PIXELS");
    ast::Frame focalFrame(2, "Domain=FOCAL");
    ast::Frame iwcFrame(2, "Domain=IWC");
 
    // make a basic SkyWcs and extract the IWC portion
    auto iwcToSkyWcs = afw::geom::makeSkyWcs(
            geom::Point2D(0, 0), geom::SpherePoint(tangentPoint.x, tangentPoint.y, geom::degrees),
            afw::geom::makeCdMatrix(1.0 * geom::degrees, 0 * geom::degrees, true));
    auto iwcToSkyMap = iwcToSkyWcs->getFrameDict()->getMapping("PIXELS", "SKY");
    auto skyFrame = iwcToSkyWcs->getFrameDict()->getFrame("SKY");
 
    ast::FrameDict frameDict(pixelFrame);
    frameDict.addFrame("PIXELS", *pixelsToFocal, focalFrame);
    frameDict.addFrame("FOCAL", *focalToIwc, iwcFrame);
    frameDict.addFrame("IWC", *iwcToSkyMap, *skyFrame);
    return std::make_shared<afw::geom::SkyWcs>(frameDict);
}

offsetParams()

void lsst::jointcal::ConstrainedAstrometryModel::offsetParams ( Eigen::VectorXd const & Delta )

overridevirtual

Dispaches the offsets after a fit step into the actual locations of parameters.

Implements lsst::jointcal::AstrometryModel.

Definition at line 172 of file ConstrainedAstrometryModel.cc.

                                                                        {
    if (_fittingChips)
        for (auto &i : _chipMap) {
            auto mapping = i.second.get();
            mapping->offsetParams(delta.segment(mapping->getIndex(), mapping->getNpar()));
        }
    if (_fittingVisits)
        for (auto &i : _visitMap) {
            auto mapping = i.second.get();
            mapping->offsetParams(delta.segment(mapping->getIndex(), mapping->getNpar()));
        }
}

operator=() [1/2]

ConstrainedAstrometryModel & lsst::jointcal::ConstrainedAstrometryModel::operator= ( ConstrainedAstrometryModel && )

delete

operator=() [2/2]

ConstrainedAstrometryModel & lsst::jointcal::ConstrainedAstrometryModel::operator= ( ConstrainedAstrometryModel const & )

delete

print()

void lsst::jointcal::ConstrainedAstrometryModel::print ( std::ostream & out ) const

overridevirtual

Print a string representation of the contents of this mapping, for debugging.

This string representation can be very verbose, as it contains all of the parameters of all of the transforms in this model.

Implements lsst::jointcal::AstrometryModel.

Definition at line 260 of file ConstrainedAstrometryModel.cc.

                                                            {
    out << "Constrained Astrometry Model (" << _mappings.size() << " composite mappings; " << _chipMap.size()
        << " sensor mappings, " << _visitMap.size() << " visit mappings):" << std::endl;
    out << *_skyToTangentPlane << std::endl;
    out << "Sensor to sky transforms:" << std::endl;
    for (auto &i : _mappings) {
        out << i.first << std::endl;
        out << *(i.second) << std::endl;
    }
}

validate()

bool lsst::jointcal::AstrometryModel::validate ( CcdImageList const & ccdImageList, int ndof ) const

inherited

Return true if this is a "reasonable" model.

Parameters

ccdImageList	The ccdImages to test the model validity on.
ndof	The number of degrees of freedom in the fit, e.g. from Fitterbase.computeChi2().

Returns

True if the model is valid on all ccdImages.

Definition at line 30 of file AstrometryModel.cc.

                                                                               {
    bool check = true;
    if (ndof < 0) {
        check &= false;
        LOGLS_ERROR(_log, "This model only has "
                                  << ndof << " degrees of freedom, with " << getTotalParameters()
                                  << " total parameters. Reduce the model complexity (e.g. polynomial order)"
                                     " to better match the number of measured sources.");
    }
    return check;
}

Member Data Documentation

_log

LOG_LOGGER lsst::jointcal::AstrometryModel::_log

protectedinherited

lsst.logging instance, to be created by a subclass so that messages have consistent name.

Definition at line 117 of file AstrometryModel.h.

---

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

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-9.0.0/Linux64/jointcal/g82479be7b0+f568feb641/include/lsst/jointcal/ConstrainedAstrometryModel.h
• /j/snowflake/release/lsstsw/stack/lsst-scipipe-9.0.0/Linux64/jointcal/g82479be7b0+f568feb641/src/ConstrainedAstrometryModel.cc