117 def fitWcs(self, matches, initWcs, bbox=None, refCat=None, sourceCat=None, exposure=None):
118 """Fit a TAN-SIP WCS from a list of reference object/source matches.
122 matches : `list` of `lsst.afw.table.ReferenceMatch`
123 A sequence of reference object/source matches.
124 The following fields are read:
125 - match.first (reference object) coord
126 - match.second (source) centroid
128 The following fields are written:
129 - match.first (reference object) centroid
130 - match.second (source) centroid
131 - match.distance (on sky separation, in radians)
133 initWcs : `lsst.afw.geom.SkyWcs`
134 An initial WCS whose CD matrix is used as the final CD matrix.
135 bbox : `lsst.geom.Box2I`
136 The region over which the WCS will be valid (PARENT pixel coordinates);
137 if `None` or an empty box then computed from matches
138 refCat : `lsst.afw.table.SimpleCatalog`
139 Reference object catalog, or `None`.
140 If provided then all centroids are updated with the new WCS,
141 otherwise only the centroids for ref objects in matches are updated.
142 Required fields are "centroid_x", "centroid_y", "coord_ra", and "coord_dec".
143 sourceCat : `lsst.afw.table.SourceCatalog`
144 Source catalog, or `None`.
145 If provided then coords are updated with the new WCS;
146 otherwise only the coords for sources in matches are updated.
147 Required input fields are "slot_Centroid_x", "slot_Centroid_y",
148 "slot_Centroid_xErr", "slot_Centroid_yErr", and optionally
149 "slot_Centroid_x_y_Cov". The "coord_ra" and "coord_dec" fields
150 will be updated but are not used as input.
151 exposure : `lsst.afw.image.Exposure`
152 An Exposure or other displayable image on which matches can be
153 overplotted. Ignored (and may be `None`) if display-based debugging
154 is not enabled via lsstDebug.
158 An lsst.pipe.base.Struct with the following fields:
159 - wcs : `lsst.afw.geom.SkyWcs`
161 - scatterOnSky : `lsst.geom.Angle`
162 The median on-sky separation between reference objects and
163 sources in "matches", as an `lsst.geom.Angle`
172 for match
in matches:
173 bbox.include(match.second.getCentroid())
185 revFitter = ScaledPolynomialTransformFitter.fromMatches(self.config.order, matches, wcs,
186 self.config.refUncertainty)
188 for nIter
in range(self.config.numRejIter):
189 revFitter.updateModel()
190 intrinsicScatter = revFitter.updateIntrinsicScatter()
193 "Iteration %s: intrinsic scatter is %4.3f pixels, "
194 "rejected %d outliers at %3.2f sigma.",
195 nIter+1, intrinsicScatter, nRejected, clippedSigma
198 displayFrame = self.
display(revFitter, exposure=exposure, bbox=bbox,
199 frame=displayFrame, displayPause=displayPause)
201 revScaledPoly = revFitter.getTransform()
205 sipReverse = SipReverseTransform.convert(revScaledPoly, wcs.getPixelOrigin(), cdMatrix)
213 gridBBoxPix.grow(self.config.gridBorder)
219 for point
in gridBBoxPix.getCorners():
221 gridBBoxIwc.include(cdMatrix(point))
222 fwdFitter = ScaledPolynomialTransformFitter.fromGrid(self.config.order, gridBBoxIwc,
223 self.config.nGridX, self.config.nGridY,
227 fwdScaledPoly = fwdFitter.getTransform()
228 sipForward = SipForwardTransform.convert(fwdScaledPoly, wcs.getPixelOrigin(), cdMatrix)
232 wcs = makeWcs(sipForward, sipReverse, wcs.getSkyOrigin())
234 if refCat
is not None:
235 self.log.debug(
"Updating centroids in refCat")
238 self.log.warning(
"Updating reference object centroids in match list; refCat is None")
241 if sourceCat
is not None:
242 self.log.debug(
"Updating coords in sourceCat")
245 self.log.warning(
"Updating source coords in match list; sourceCat is None")
248 self.log.debug(
"Updating distance in match list")
249 setMatchDistance(matches)
251 stats = makeMatchStatisticsInRadians(wcs, matches, lsst.afw.math.MEDIAN)
252 scatterOnSky = stats.getValue()*lsst.geom.radians
254 if scatterOnSky.asArcseconds() > self.config.maxScatterArcsec:
255 raise lsst.pipe.base.TaskError(
256 "Fit failed: median scatter on sky = %0.3f arcsec > %0.3f config.maxScatterArcsec" %
257 (scatterOnSky.asArcseconds(), self.config.maxScatterArcsec))
259 return lsst.pipe.base.Struct(
261 scatterOnSky=scatterOnSky,
264 def display(self, revFitter, exposure=None, bbox=None, frame=0, pause=True):
265 """Display positions and outlier status overlaid on an image.
267 This method is called by fitWcs when display debugging is enabled. It
268 always drops into pdb before returning to allow interactive inspection,
269 and hence it should never be called in non-interactive contexts.
273 revFitter : :cpp:class:`lsst::meas::astrom::ScaledPolynomialTransformFitter`
274 Fitter object initialized with `fromMatches` for fitting a "reverse"
275 distortion: the mapping from intermediate world coordinates to
277 exposure : :cpp:class:`lsst::afw::image::Exposure`
278 An Exposure or other displayable image on which matches can be
280 bbox : :cpp:class:`lsst::afw::geom::Box2I`
281 Bounding box of the region on which matches should be plotted.
283 data = revFitter.getData()
284 disp = lsst.afw.display.getDisplay(frame=frame)
285 if exposure
is not None:
287 elif bbox
is not None:
288 disp.mtv(exposure=lsst.afw.image.ExposureF(bbox))
290 raise TypeError(
"At least one of 'exposure' and 'bbox' must be provided.")
291 data = revFitter.getData()
296 rejectedKey = data.schema.find(
"rejected").key
297 with disp.Buffering():
299 colors = ((lsst.afw.display.RED, lsst.afw.display.GREEN)
300 if not record.get(rejectedKey)
else
301 (lsst.afw.display.MAGENTA, lsst.afw.display.CYAN))
302 rx, ry = record.get(refKey)
303 disp.dot(
"x", rx, ry, size=10, ctype=colors[0])
304 mx, my = record.get(modelKey)
305 disp.dot(
"o", mx, my, size=10, ctype=colors[0])
306 disp.line([(rx, ry), (mx, my)], ctype=colors[0])
307 sx, sy = record.get(srcKey)
308 sErr = record.get(srcErrKey)
309 sEllipse = lsst.afw.geom.Quadrupole(sErr[0, 0], sErr[1, 1], sErr[0, 1])
310 disp.dot(sEllipse, sx, sy, ctype=colors[1])
311 if pause
or pause
is None:
312 print(
"Dropping into debugger to allow inspection of display. Type 'continue' when done.")