lsst.meas.algorithms  13.0-23-gb99accf8+14
CoaddPsf.cc
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2 
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24 
25 /*
26  * Represent a PSF as for a Coadd based on the James Jee stacking
27  * algorithm which was extracted from Stackfit.
28  */
29 #include <cmath>
30 #include <sstream>
31 #include <iostream>
32 #include <numeric>
33 #include "boost/iterator/iterator_adaptor.hpp"
34 #include "boost/iterator/transform_iterator.hpp"
35 #include "ndarray/eigen.h"
36 #include "lsst/base.h"
37 #include "lsst/pex/exceptions.h"
38 #include "lsst/afw/image/ImageUtils.h"
39 #include "lsst/afw/math/Statistics.h"
41 #include "lsst/afw/table/io/OutputArchive.h"
42 #include "lsst/afw/table/io/InputArchive.h"
43 #include "lsst/afw/table/io/CatalogVector.h"
45 
46 namespace lsst {
47 namespace meas {
48 namespace algorithms {
49 
50 namespace {
51 
52 // Struct used to simplify calculations in computeAveragePosition; lets us use
53 // std::accumulate instead of explicit for loop.
54 struct AvgPosItem {
55  double wx; // weighted x position
56  double wy; // weighted y position
57  double w; // weight value
58 
59  explicit AvgPosItem(double wx_=0.0, double wy_=0.0, double w_=0.0) : wx(wx_), wy(wy_), w(w_) {}
60 
61  // return point, assuming this is a sum of many AvgPosItems
62  afw::geom::Point2D getPoint() const { return afw::geom::Point2D(wx/w, wy/w); }
63 
64  // comparison so we can sort by weights
65  bool operator<(AvgPosItem const & other) const {
66  return w < other.w;
67  }
68 
69  AvgPosItem & operator+=(AvgPosItem const & other) {
70  wx += other.wx;
71  wy += other.wy;
72  w += other.w;
73  return *this;
74  }
75 
76  AvgPosItem & operator-=(AvgPosItem const & other) {
77  wx -= other.wx;
78  wy -= other.wy;
79  w -= other.w;
80  return *this;
81  }
82 
83  friend AvgPosItem operator+(AvgPosItem a, AvgPosItem const & b) { return a += b; }
84 
85  friend AvgPosItem operator-(AvgPosItem a, AvgPosItem const & b) { return a -= b; }
86 };
87 
88 afw::geom::Point2D computeAveragePosition(
89  afw::table::ExposureCatalog const & catalog,
90  afw::image::Wcs const & coaddWcs,
91  afw::table::Key<double> weightKey
92 ) {
93  afw::table::Key<int> goodPixKey;
94  try {
95  goodPixKey = catalog.getSchema()["goodpix"];
96  } catch (pex::exceptions::NotFoundError &) {}
97  std::vector<AvgPosItem> items;
98  items.reserve(catalog.size());
99  for (afw::table::ExposureCatalog::const_iterator i = catalog.begin(); i != catalog.end(); ++i) {
100  afw::geom::Point2D p = coaddWcs.skyToPixel(
101  *i->getWcs()->pixelToSky(
102  i->getPsf()->getAveragePosition()
103  )
104  );
105  AvgPosItem item(p.getX(), p.getY(), i->get(weightKey));
106  if (goodPixKey.isValid()) {
107  item.w *= i->get(goodPixKey);
108  }
109  item.wx *= item.w;
110  item.wy *= item.w;
111  items.push_back(item);
112  }
113  // This is a bit pessimistic - we save and sort all the weights all the time,
114  // even though we'll only need them if the average position from all of them
115  // is invalid. But it makes for simpler code, and it's not that expensive
116  // computationally anyhow.
117  std::sort(items.begin(), items.end());
118  AvgPosItem result = std::accumulate(items.begin(), items.end(), AvgPosItem());
119  // If the position isn't valid (no input frames contain it), we remove frames
120  // from the average until it does.
121  for (
122  std::vector<AvgPosItem>::iterator iter = items.begin();
123  catalog.subsetContaining(result.getPoint(), coaddWcs, true).empty();
124  ++iter
125  ) {
126  if (iter == items.end()) {
127  // This should only happen if there are no inputs at all,
128  // or if constituent Psfs have a badly-behaved implementation
129  // of getAveragePosition().
130  throw LSST_EXCEPT(
131  pex::exceptions::RuntimeError,
132  "Could not find a valid average position for CoaddPsf"
133  );
134  }
135  result -= *iter;
136  }
137  return result.getPoint();
138 }
139 
140 } // anonymous
141 
143  afw::table::ExposureCatalog const & catalog,
144  afw::image::Wcs const & coaddWcs,
145  std::string const & weightFieldName,
146  std::string const & warpingKernelName,
147  int cacheSize
148 ) :
149  _coaddWcs(coaddWcs.clone()),
150  _warpingKernelName(warpingKernelName),
151  _warpingControl(std::make_shared<afw::math::WarpingControl>(warpingKernelName, "", cacheSize))
152 {
153  afw::table::SchemaMapper mapper(catalog.getSchema());
154  mapper.addMinimalSchema(afw::table::ExposureTable::makeMinimalSchema(), true);
155 
156  // copy the field "goodpix", if available, for computeAveragePosition to use
157  try {
158  afw::table::Key<int> goodPixKey = catalog.getSchema()["goodpix"]; // auto does not work
159  mapper.addMapping(goodPixKey, true);
160  } catch (pex::exceptions::NotFoundError &) {}
161 
162  // copy the field specified by weightFieldName to field "weight"
163  afw::table::Field<double> weightField = afw::table::Field<double>("weight", "Coadd weight");
164  afw::table::Key<double> weightKey = catalog.getSchema()[weightFieldName];
165  _weightKey = mapper.addMapping(weightKey, weightField);
166 
167  _catalog = afw::table::ExposureCatalog(mapper.getOutputSchema());
168  for (afw::table::ExposureCatalog::const_iterator i = catalog.begin(); i != catalog.end(); ++i) {
169  PTR(afw::table::ExposureRecord) record = _catalog.getTable()->makeRecord();
170  record->assign(*i, mapper);
171  _catalog.push_back(record);
172  }
173  _averagePosition = computeAveragePosition(_catalog, *_coaddWcs, _weightKey);
174 }
175 
176 PTR(afw::detection::Psf) CoaddPsf::clone() const {
177  return std::make_shared<CoaddPsf>(*this);
178 }
179 
180 PTR(afw::detection::Psf) CoaddPsf::resized(int width, int height) const {
181  // Not implemented for WarpedPsf
182  throw LSST_EXCEPT(pex::exceptions::LogicError, "Not Implemented");
183  }
184 
185 // Read all the images from the Image Vector and return the BBox in xy0 offset coordinates
186 
187 afw::geom::Box2I getOverallBBox(std::vector<PTR(afw::image::Image<double>)> const & imgVector) {
188 
189  afw::geom::Box2I bbox;
190  // Calculate the box which will contain them all
191  for (unsigned int i = 0; i < imgVector.size(); i ++) {
192  PTR(afw::image::Image<double>) componentImg = imgVector[i];
193  afw::geom::Box2I cBBox = componentImg->getBBox();
194  bbox.include(cBBox); // JFB: this works even on empty bboxes
195  }
196  return bbox;
197 }
198 
199 
200 // Read all the images from the Image Vector and add them to image
201 
204  std::vector<PTR(afw::image::Image<double>)> const & imgVector,
205  std::vector<double> const & weightVector
206 ) {
207  assert(imgVector.size() == weightVector.size());
208  for (unsigned int i = 0; i < imgVector.size(); i ++) {
209  PTR(afw::image::Image<double>) componentImg = imgVector[i];
210  double weight = weightVector[i];
211  double sum = componentImg->getArray().asEigen().sum();
212 
213  // Now get the portion of the component image which is appropriate to add
214  // If the default image size is used, the component is guaranteed to fit,
215  // but not if a size has been specified.
216  afw::geom::Box2I cBBox = componentImg->getBBox();
217  afw::geom::Box2I overlap(cBBox);
218  overlap.clip(image->getBBox());
219  // JFB: A subimage view of the image we want to add to, containing only the overlap region.
220  afw::image::Image<double> targetSubImage(*image, overlap);
221  // JFB: A subimage view of the image we want to add from, containing only the overlap region.
222  afw::image::Image<double> cSubImage(*componentImg, overlap);
223  targetSubImage.scaledPlus(weight/sum, cSubImage);
224  }
225 }
226 
227 
228 afw::geom::Box2I CoaddPsf::doComputeBBox(
229  afw::geom::Point2D const & ccdXY,
230  afw::image::Color const & color
231 ) const {
232  afw::table::ExposureCatalog subcat = _catalog.subsetContaining(ccdXY, *_coaddWcs, true);
233  if (subcat.empty()) {
234  throw LSST_EXCEPT(
235  pex::exceptions::InvalidParameterError,
236  (boost::format("Cannot compute BBox at point %s; no input images at that point.")
237  % ccdXY).str());
238  }
239 
240  afw::geom::Box2I ret;
241  for (auto const & exposureRecord : subcat) {
242  PTR(afw::geom::XYTransform) xytransform(
243  new afw::image::XYTransformFromWcsPair(_coaddWcs, exposureRecord.getWcs()));
244  WarpedPsf warpedPsf = WarpedPsf(exposureRecord.getPsf(), xytransform, _warpingControl);
245  afw::geom::Box2I componentBBox = warpedPsf.computeBBox(ccdXY, color);
246  ret.include(componentBBox);
247  }
248 
249  return ret;
250 }
251 
252 PTR(afw::detection::Psf::Image) CoaddPsf::doComputeKernelImage(
253  afw::geom::Point2D const & ccdXY,
254  afw::image::Color const & color
255 ) const {
256  // Get the subset of expoures which contain our coordinate within their validPolygons.
257  afw::table::ExposureCatalog subcat = _catalog.subsetContaining(ccdXY, *_coaddWcs, true);
258  if (subcat.empty()) {
259  throw LSST_EXCEPT(
260  pex::exceptions::InvalidParameterError,
261  (boost::format("Cannot compute CoaddPsf at point %s; no input images at that point.")
262  % ccdXY).str()
263  );
264  }
265  double weightSum = 0.0;
266 
267  // Read all the Psf images into a vector. The code is set up so that this can be done in chunks,
268  // with the image modified to accomodate
269  // However, we currently read all of the images.
270  std::vector<PTR(afw::image::Image<double>)> imgVector;
271  std::vector<double> weightVector;
272 
273  for (auto const & exposureRecord : subcat) {
274  PTR(afw::geom::XYTransform) xytransform(
275  new afw::image::XYTransformFromWcsPair(_coaddWcs, exposureRecord.getWcs())
276  );
277  WarpedPsf warpedPsf = WarpedPsf(exposureRecord.getPsf(), xytransform, _warpingControl);
278  PTR(afw::image::Image<double>) componentImg = warpedPsf.computeKernelImage(ccdXY, color);
279  imgVector.push_back(componentImg);
280  weightSum += exposureRecord.get(_weightKey);
281  weightVector.push_back(exposureRecord.get(_weightKey));
282  }
283 
284  afw::geom::Box2I bbox = getOverallBBox(imgVector);
285 
286  // create a zero image of the right size to sum into
287  PTR(afw::detection::Psf::Image) image = std::make_shared<afw::detection::Psf::Image>(bbox);
288  *image = 0.0;
289  addToImage(image, imgVector, weightVector);
290  *image /= weightSum;
291  return image;
292 }
293 
295  return _catalog.size();
296 }
297 
298 CONST_PTR(afw::detection::Psf) CoaddPsf::getPsf(int index) {
299  if (index < 0 || index > getComponentCount()) {
300  throw LSST_EXCEPT(pex::exceptions::RangeError, "index of CoaddPsf component out of range");
301  }
302  return _catalog[index].getPsf();
303 }
304 
305 CONST_PTR(afw::image::Wcs) CoaddPsf::getWcs(int index) {
306  if (index < 0 || index > getComponentCount()) {
307  throw LSST_EXCEPT(pex::exceptions::RangeError, "index of CoaddPsf component out of range");
308  }
309  return _catalog[index].getWcs();
310 }
311 
312 CONST_PTR(afw::geom::polygon::Polygon) CoaddPsf::getValidPolygon(int index) {
313  if (index < 0 || index > getComponentCount()) {
314  throw LSST_EXCEPT(pex::exceptions::RangeError, "index of CoaddPsf component out of range");
315  }
316  return _catalog[index].getValidPolygon();
317 }
318 
319 double CoaddPsf::getWeight(int index) {
320  if (index < 0 || index > getComponentCount()) {
321  throw LSST_EXCEPT(pex::exceptions::RangeError, "index of CoaddPsf component out of range");
322  }
323  return _catalog[index].get(_weightKey);
324 }
325 
326 afw::table::RecordId CoaddPsf::getId(int index) {
327  if (index < 0 || index > getComponentCount()) {
328  throw LSST_EXCEPT(pex::exceptions::RangeError, "index of CoaddPsf component out of range");
329  }
330  return _catalog[index].getId();
331 }
332 
333 afw::geom::Box2I CoaddPsf::getBBox(int index) {
334  if (index < 0 || index > getComponentCount()) {
335  throw LSST_EXCEPT(pex::exceptions::RangeError, "index of CoaddPsf component out of range");
336  }
337  return _catalog[index].getBBox();
338 }
339 
340 // ---------- Persistence -----------------------------------------------------------------------------------
341 
342 // For persistence of CoaddPsf, we have two catalogs: the first has just one record, and contains
343 // the archive ID of the coadd WCS, the size of the warping cache, the name of the warping kernel,
344 // and the average position. The latter is simply the ExposureCatalog.
345 
346 namespace {
347 
348 namespace tbl = afw::table;
349 
350 // Singleton class that manages the first persistence catalog's schema and keys
351 class CoaddPsfPersistenceHelper {
352 public:
353  tbl::Schema schema;
354  tbl::Key<int> coaddWcs;
355  tbl::Key<int> cacheSize;
356  tbl::PointKey<double> averagePosition;
357  tbl::Key<std::string> warpingKernelName;
358 
359  static CoaddPsfPersistenceHelper const & get() {
360  static CoaddPsfPersistenceHelper const instance;
361  return instance;
362  }
363 
364 private:
365  CoaddPsfPersistenceHelper() :
366  schema(),
367  coaddWcs(schema.addField<int>("coaddwcs", "archive ID of the coadd's WCS")),
368  cacheSize(schema.addField<int>("cachesize", "size of the warping cache")),
369  averagePosition(tbl::PointKey<double>::addFields(
370  schema, "avgpos", "PSF accessors default position", "pixel"
371  )),
372  warpingKernelName(schema.addField<std::string>("warpingkernelname", "warping kernel name", 32))
373  {
374  schema.getCitizen().markPersistent();
375  }
376 };
377 
378 } // anonymous
379 
380 class CoaddPsf::Factory : public tbl::io::PersistableFactory {
381 public:
382 
383  virtual PTR(tbl::io::Persistable)
384  read(InputArchive const & archive, CatalogVector const & catalogs) const {
385  if (catalogs.size() == 1u) {
386  // Old CoaddPsfs were saved in only one catalog, because we didn't
387  // save the warping parameters and average position, and we could
388  // save the coadd Wcs in a special final record.
389  return readV0(archive, catalogs);
390  }
391  LSST_ARCHIVE_ASSERT(catalogs.size() == 2u);
392  CoaddPsfPersistenceHelper const & keys1 = CoaddPsfPersistenceHelper::get();
393  LSST_ARCHIVE_ASSERT(catalogs.front().getSchema() == keys1.schema);
394  tbl::BaseRecord const & record1 = catalogs.front().front();
395  return PTR(CoaddPsf)(
396  new CoaddPsf(
397  tbl::ExposureCatalog::readFromArchive(archive, catalogs.back()),
398  archive.get<afw::image::Wcs>(record1.get(keys1.coaddWcs)),
399  record1.get(keys1.averagePosition),
400  record1.get(keys1.warpingKernelName),
401  record1.get(keys1.cacheSize)
402  )
403  );
404  }
405 
406 
407  // Backwards compatibility for files saved before meas_algorithms commit
408  // 53e61fae (7/10/2013). Prior to that change, the warping configuration
409  // and the average position were not saved at all, making it impossible to
410  // reconstruct the average position exactly, but it's better to
411  // approximate than to fail completely.
412  std::shared_ptr<tbl::io::Persistable>
413  readV0(InputArchive const & archive, CatalogVector const & catalogs) const {
414  auto internalCat = tbl::ExposureCatalog::readFromArchive(archive, catalogs.front());
415  // Coadd WCS is stored in a special last record.
416  auto coaddWcs = internalCat.back().getWcs();
417  internalCat.pop_back();
418  // Attempt to reconstruct the average position. We can't do this
419  // exactly, since the catalog we saved isn't the same one that was
420  // used to compute the original average position.
421  tbl::Key<double> weightKey;
422  try {
423  weightKey = internalCat.getSchema()["weight"];
424  } catch (pex::exceptions::NotFoundError &) {}
425  auto averagePos = computeAveragePosition(internalCat, *coaddWcs, weightKey);
426  return std::shared_ptr<CoaddPsf>(new CoaddPsf(internalCat, coaddWcs, averagePos));
427  }
428 
429  Factory(std::string const & name) : tbl::io::PersistableFactory(name) {}
430 
431 };
432 
433 namespace {
434 
435 std::string getCoaddPsfPersistenceName() { return "CoaddPsf"; }
436 
437 CoaddPsf::Factory registration(getCoaddPsfPersistenceName());
438 
439 } // anonymous
440 
441 std::string CoaddPsf::getPersistenceName() const { return getCoaddPsfPersistenceName(); }
442 
443 std::string CoaddPsf::getPythonModule() const { return "lsst.meas.algorithms"; }
444 
445 void CoaddPsf::write(OutputArchiveHandle & handle) const {
446  CoaddPsfPersistenceHelper const & keys1 = CoaddPsfPersistenceHelper::get();
447  tbl::BaseCatalog cat1 = handle.makeCatalog(keys1.schema);
448  PTR(tbl::BaseRecord) record1 = cat1.addNew();
449  record1->set(keys1.coaddWcs, handle.put(_coaddWcs));
450  record1->set(keys1.cacheSize, _warpingControl->getCacheSize());
451  record1->set(keys1.averagePosition, _averagePosition);
452  record1->set(keys1.warpingKernelName, _warpingKernelName);
453  handle.saveCatalog(cat1);
454  _catalog.writeToArchive(handle, false);
455 }
456 
458  afw::table::ExposureCatalog const & catalog,
459  PTR(afw::image::Wcs const) coaddWcs,
460  afw::geom::Point2D const & averagePosition,
461  std::string const & warpingKernelName,
462  int cacheSize
463 ) :
464  _catalog(catalog), _coaddWcs(coaddWcs), _weightKey(_catalog.getSchema()["weight"]),
465  _averagePosition(averagePosition), _warpingKernelName(warpingKernelName),
466  _warpingControl(new afw::math::WarpingControl(warpingKernelName, "", cacheSize))
467 {}
468 
469 }}} // namespace lsst::meas::algorithms
470 
471 
afw::geom::Box2I getOverallBBox(std::vector< boost::shared_ptr< afw::image::Image< double > >> const &imgVector)
Definition: CoaddPsf.cc:187
tbl::Key< double > weight
afw::geom::Box2I getBBox(int index)
Get the bounding box (in component image Pixel coordinates) of the component image at index...
Definition: CoaddPsf.cc:333
double getWeight(int index)
Get the weight of the component image at index.
Definition: CoaddPsf.cc:319
virtual std::string getPythonModule() const
Definition: CoaddPsf.cc:443
STL namespace.
boost::shared_ptr< afw::image::Wcs const > getWcs(int index)
Get the Wcs of the component image at index.
Definition: CoaddPsf.cc:305
CoaddPsf(afw::table::ExposureCatalog const &catalog, afw::image::Wcs const &coaddWcs, std::string const &weightFieldName="weight", std::string const &warpingKernelName="lanczos3", int cacheSize=10000)
Main constructors for CoaddPsf.
Definition: CoaddPsf.cc:142
virtual boost::shared_ptr< afw::detection::Psf > resized(int width, int height) const
Return a clone with specified kernel dimensions.
Definition: CoaddPsf.cc:180
virtual std::string getPersistenceName() const
Definition: CoaddPsf.cc:441
virtual void write(OutputArchiveHandle &handle) const
Definition: CoaddPsf.cc:445
tbl::Key< int > cacheSize
Definition: CoaddPsf.cc:355
int getComponentCount() const
Return the number of component Psfs in this CoaddPsf.
Definition: CoaddPsf.cc:294
afw::table::RecordId getId(int index)
Get the exposure ID of the component image at index.
Definition: CoaddPsf.cc:326
Factory(std::string const &name)
Definition: CoaddPsf.cc:429
virtual afw::geom::Box2I doComputeBBox(afw::geom::Point2D const &position, afw::image::Color const &color) const
Definition: CoaddPsf.cc:228
double w
Definition: CoaddPsf.cc:57
tbl::Schema schema
Definition: CoaddPsf.cc:353
CoaddPsf is the Psf derived to be used for non-PSF-matched Coadd images.
Definition: CoaddPsf.h:58
double wx
Definition: CoaddPsf.cc:55
boost::shared_ptr< afw::detection::Psf::Image > doComputeKernelImage(afw::geom::Point2D const &ccdXY, afw::image::Color const &color) const
Definition: CoaddPsf.cc:252
tbl::Key< std::string > warpingKernelName
Definition: CoaddPsf.cc:357
virtual boost::shared_ptr< afw::detection::Psf > clone() const
Polymorphic deep copy. Usually unnecessary, as Psfs are immutable.
Definition: CoaddPsf.cc:176
void addToImage(boost::shared_ptr< afw::image::Image< double > > image, std::vector< boost::shared_ptr< afw::image::Image< double > >> const &imgVector, std::vector< double > const &weightVector)
Definition: CoaddPsf.cc:202
tbl::Key< int > coaddWcs
Definition: CoaddPsf.cc:354
afw::table::Key< double > b
tbl::PointKey< double > averagePosition
Definition: CoaddPsf.cc:356
double wy
Definition: CoaddPsf.cc:56
std::shared_ptr< tbl::io::Persistable > readV0(InputArchive const &archive, CatalogVector const &catalogs) const
Definition: CoaddPsf.cc:413
A Psf class that maps an arbitrary Psf through a coordinate transformation.
Definition: WarpedPsf.h:49
boost::shared_ptr< afw::detection::Psf const > getPsf(int index)
Get the Psf of the component image at index.
Definition: CoaddPsf.cc:298
boost::shared_ptr< afw::geom::polygon::Polygon const > getValidPolygon(int index)
Get the validPolygon (in component image Pixel coordinates) of the component image at index...
Definition: CoaddPsf.cc:312