Public Member Functions |
Static Public Attributes |
Protected Member Functions |
Static Protected Attributes |
List of all members
lsst.ip.isr.fringe.FringeTask Class Reference
Inheritance diagram for lsst.ip.isr.fringe.FringeTask:
Public Member Functions | |
| loadFringes (self, fringeExp, expId=None, assembler=None) | |
| run (self, exposure, fringes, seed=None) | |
| checkFilter (self, exposure) | |
| removePedestal (self, fringe) | |
| generatePositions (self, exposure, rng) | |
| measureExposure (self, exposure, positions, title="Fringe") | |
| solve (self, science, fringes) | |
| subtract (self, science, fringes, solution) | |
Static Public Attributes | |
| ConfigClass = FringeConfig | |
Protected Member Functions | |
| _solve (self, science, fringes) | |
Static Protected Attributes | |
| str | _DefaultName = 'isrFringe' |
Detailed Description
Task to remove fringes from a science exposure We measure fringe amplitudes at random positions on the science exposure and at the same positions on the (potentially multiple) fringe frames and solve for the scales simultaneously.
Member Function Documentation
◆ _solve()
|
protected |
Solve for the scale factors.
Parameters
----------
science : `numpy.array`
Array of measured science image values at each of the
positions supplied.
fringes : `numpy.array`
Array of measured fringe values at each of the positions
supplied.
Returns
-------
solution : `np.array`
Fringe solution amplitudes for each input fringe frame.
Definition at line 408 of file fringe.py.
408 def _solve(self, science, fringes):
409 """Solve for the scale factors.
410
411 Parameters
412 ----------
413 science : `numpy.array`
414 Array of measured science image values at each of the
415 positions supplied.
416 fringes : `numpy.array`
417 Array of measured fringe values at each of the positions
418 supplied.
419
420 Returns
421 -------
422 solution : `np.array`
423 Fringe solution amplitudes for each input fringe frame.
424 """
425 return afwMath.LeastSquares.fromDesignMatrix(fringes, science,
426 afwMath.LeastSquares.DIRECT_SVD).getSolution()
427
◆ checkFilter()
| lsst.ip.isr.fringe.FringeTask.checkFilter | ( | self, | |
| exposure ) |
Check whether we should fringe-subtract the science exposure.
Parameters
----------
exposure : `lsst.afw.image.Exposure`
Exposure to check the filter of.
Returns
-------
needsFringe : `bool`
If True, then the exposure has a filter listed in the
configuration, and should have the fringe applied.
Definition at line 184 of file fringe.py.
184 def checkFilter(self, exposure):
185 """Check whether we should fringe-subtract the science exposure.
186
187 Parameters
188 ----------
189 exposure : `lsst.afw.image.Exposure`
190 Exposure to check the filter of.
191
192 Returns
193 -------
194 needsFringe : `bool`
195 If True, then the exposure has a filter listed in the
196 configuration, and should have the fringe applied.
197 """
198 return checkFilter(exposure, self.config.filters, log=self.log)
199
◆ generatePositions()
| lsst.ip.isr.fringe.FringeTask.generatePositions | ( | self, | |
| exposure, | |||
| rng ) |
Generate a random distribution of positions for measuring fringe
amplitudes.
Parameters
----------
exposure : `lsst.afw.image.Exposure`
Exposure to measure the positions on.
rng : `numpy.random.RandomState`
Random number generator to use.
Returns
-------
positions : `numpy.array`
Two-dimensional array containing the positions to sample
for fringe amplitudes.
Definition at line 216 of file fringe.py.
216 def generatePositions(self, exposure, rng):
217 """Generate a random distribution of positions for measuring fringe
218 amplitudes.
219
220 Parameters
221 ----------
222 exposure : `lsst.afw.image.Exposure`
223 Exposure to measure the positions on.
224 rng : `numpy.random.RandomState`
225 Random number generator to use.
226
227 Returns
228 -------
229 positions : `numpy.array`
230 Two-dimensional array containing the positions to sample
231 for fringe amplitudes.
232 """
233 start = self.config.large
234 num = self.config.num
235 width = exposure.getWidth() - self.config.large
236 height = exposure.getHeight() - self.config.large
237 return numpy.array([rng.randint(start, width, size=num),
238 rng.randint(start, height, size=num)]).swapaxes(0, 1)
239
◆ loadFringes()
| lsst.ip.isr.fringe.FringeTask.loadFringes | ( | self, | |
| fringeExp, | |||
| expId = None, | |||
| assembler = None ) |
Pack the fringe data into a Struct.
This method moves the struct parsing code into a butler
generation agnostic handler.
Parameters
----------
fringeExp : `lsst.afw.exposure.Exposure`
The exposure containing the fringe data.
expId : `int`, optional
Exposure id to be fringe corrected, used to set RNG seed.
assembler : `lsst.ip.isr.AssembleCcdTask`, optional
An instance of AssembleCcdTask (for assembling fringe
frames).
Returns
-------
fringeData : `pipeBase.Struct`
Struct containing fringe data:
``fringes``
Calibration fringe files containing master fringe frames.
( : `lsst.afw.image.Exposure` or `list` thereof)
``seed``
Seed for random number generation. (`int`, optional)
Definition at line 85 of file fringe.py.
85 def loadFringes(self, fringeExp, expId=None, assembler=None):
86 """Pack the fringe data into a Struct.
87
88 This method moves the struct parsing code into a butler
89 generation agnostic handler.
90
91 Parameters
92 ----------
93 fringeExp : `lsst.afw.exposure.Exposure`
94 The exposure containing the fringe data.
95 expId : `int`, optional
96 Exposure id to be fringe corrected, used to set RNG seed.
97 assembler : `lsst.ip.isr.AssembleCcdTask`, optional
98 An instance of AssembleCcdTask (for assembling fringe
99 frames).
100
101 Returns
102 -------
103 fringeData : `pipeBase.Struct`
104 Struct containing fringe data:
105
106 ``fringes``
107 Calibration fringe files containing master fringe frames.
108 ( : `lsst.afw.image.Exposure` or `list` thereof)
109 ``seed``
110 Seed for random number generation. (`int`, optional)
111 """
112 if assembler is not None:
113 fringeExp = assembler.assembleCcd(fringeExp)
114
115 if expId is None:
116 seed = self.config.stats.rngSeedOffset
117 else:
118 self.log.debug("Seeding with offset %d and ccdExposureId %d.",
119 self.config.stats.rngSeedOffset, expId)
120 seed = self.config.stats.rngSeedOffset + expId
121
122 # Seed for numpy.random.RandomState must be convertable to a 32 bit
123 # unsigned integer.
124 seed %= 2**32
125
126 return Struct(fringes=fringeExp,
127 seed=seed)
128
◆ measureExposure()
| lsst.ip.isr.fringe.FringeTask.measureExposure | ( | self, | |
| exposure, | |||
| positions, | |||
| title = "Fringe" ) |
Measure fringe amplitudes for an exposure
The fringe amplitudes are measured as the statistic within a square
aperture. The statistic within a larger aperture are subtracted so
as to remove the background.
Parameters
----------
exposure : `lsst.afw.image.Exposure`
Exposure to measure the positions on.
positions : `numpy.array`
Two-dimensional array containing the positions to sample
for fringe amplitudes.
title : `str`, optional
Title used for debug out plots.
Returns
-------
fringes : `numpy.array`
Array of measured exposure values at each of the positions
supplied.
Definition at line 241 of file fringe.py.
241 def measureExposure(self, exposure, positions, title="Fringe"):
242 """Measure fringe amplitudes for an exposure
243
244 The fringe amplitudes are measured as the statistic within a square
245 aperture. The statistic within a larger aperture are subtracted so
246 as to remove the background.
247
248 Parameters
249 ----------
250 exposure : `lsst.afw.image.Exposure`
251 Exposure to measure the positions on.
252 positions : `numpy.array`
253 Two-dimensional array containing the positions to sample
254 for fringe amplitudes.
255 title : `str`, optional
256 Title used for debug out plots.
257
258 Returns
259 -------
260 fringes : `numpy.array`
261 Array of measured exposure values at each of the positions
262 supplied.
263 """
264 stats = afwMath.StatisticsControl()
265 stats.setNumSigmaClip(self.config.stats.clip)
266 stats.setNumIter(self.config.stats.iterations)
267 stats.setAndMask(exposure.getMaskedImage().getMask().getPlaneBitMask(self.config.stats.badMaskPlanes))
268
269 num = self.config.num
270 fringes = numpy.ndarray(num)
271
272 for i in range(num):
273 x, y = positions[i]
274 small = measure(exposure.getMaskedImage(), x, y, self.config.small, self.config.stats.stat, stats)
275 large = measure(exposure.getMaskedImage(), x, y, self.config.large, self.config.stats.stat, stats)
276 fringes[i] = small - large
277
278 import lsstDebug
279 display = lsstDebug.Info(__name__).display
280 if display:
281 disp = afwDisplay.Display(frame=getFrame())
282 disp.mtv(exposure, title=title)
283 if False:
284 with disp.Buffering():
285 for x, y in positions:
286 corners = numpy.array([[-1, -1], [1, -1], [1, 1], [-1, 1], [-1, -1]]) + [[x, y]]
287 disp.line(corners*self.config.small, ctype=afwDisplay.GREEN)
288 disp.line(corners*self.config.large, ctype=afwDisplay.BLUE)
289
290 return fringes
291
Definition lsstDebug.py:28
◆ removePedestal()
| lsst.ip.isr.fringe.FringeTask.removePedestal | ( | self, | |
| fringe ) |
Remove pedestal from fringe exposure.
Parameters
----------
fringe : `lsst.afw.image.Exposure`
Fringe data to subtract the pedestal value from.
Definition at line 200 of file fringe.py.
200 def removePedestal(self, fringe):
201 """Remove pedestal from fringe exposure.
202
203 Parameters
204 ----------
205 fringe : `lsst.afw.image.Exposure`
206 Fringe data to subtract the pedestal value from.
207 """
208 stats = afwMath.StatisticsControl()
209 stats.setNumSigmaClip(self.config.stats.clip)
210 stats.setNumIter(self.config.stats.iterations)
211 mi = fringe.getMaskedImage()
212 pedestal = afwMath.makeStatistics(mi, afwMath.MEDIAN, stats).getValue()
213 self.log.info("Removing fringe pedestal: %f", pedestal)
214 mi -= pedestal
215
Statistics makeStatistics(lsst::afw::image::Image< Pixel > const &img, lsst::afw::image::Mask< image::MaskPixel > const &msk, int const flags, StatisticsControl const &sctrl=StatisticsControl())
Handle a watered-down front-end to the constructor (no variance)
Definition Statistics.h:361
◆ run()
| lsst.ip.isr.fringe.FringeTask.run | ( | self, | |
| exposure, | |||
| fringes, | |||
| seed = None ) |
Remove fringes from the provided science exposure.
Primary method of FringeTask. Fringes are only subtracted if the
science exposure has a filter listed in the configuration.
Parameters
----------
exposure : `lsst.afw.image.Exposure`
Science exposure from which to remove fringes.
fringes : `lsst.afw.image.Exposure` or `list` thereof
Calibration fringe files containing master fringe frames.
seed : `int`, optional
Seed for random number generation.
Returns
-------
solution : `np.array`
Fringe solution amplitudes for each input fringe frame.
rms : `float`
RMS error for the fit solution for this exposure.
Definition at line 130 of file fringe.py.
130 def run(self, exposure, fringes, seed=None):
131 """Remove fringes from the provided science exposure.
132
133 Primary method of FringeTask. Fringes are only subtracted if the
134 science exposure has a filter listed in the configuration.
135
136 Parameters
137 ----------
138 exposure : `lsst.afw.image.Exposure`
139 Science exposure from which to remove fringes.
140 fringes : `lsst.afw.image.Exposure` or `list` thereof
141 Calibration fringe files containing master fringe frames.
142 seed : `int`, optional
143 Seed for random number generation.
144
145 Returns
146 -------
147 solution : `np.array`
148 Fringe solution amplitudes for each input fringe frame.
149 rms : `float`
150 RMS error for the fit solution for this exposure.
151 """
152 import lsstDebug
153 display = lsstDebug.Info(__name__).display
154
155 if not self.checkFilter(exposure):
156 self.log.info("Filter not found in FringeTaskConfig.filters. Skipping fringe correction.")
157 return
158
159 if seed is None:
160 seed = self.config.stats.rngSeedOffset
161 rng = numpy.random.RandomState(seed=seed)
162
163 if not hasattr(fringes, '__iter__'):
164 fringes = [fringes]
165
166 mask = exposure.getMaskedImage().getMask()
167 for fringe in fringes:
168 fringe.getMaskedImage().getMask().__ior__(mask)
169 if self.config.pedestal:
170 self.removePedestal(fringe)
171
172 positions = self.generatePositions(fringes[0], rng)
173 fluxes = numpy.ndarray([self.config.num, len(fringes)])
174 for i, f in enumerate(fringes):
175 fluxes[:, i] = self.measureExposure(f, positions, title="Fringe frame")
176
177 expFringes = self.measureExposure(exposure, positions, title="Science")
178 solution, rms = self.solve(expFringes, fluxes)
179 self.subtract(exposure, fringes, solution)
180 if display:
181 afwDisplay.Display(frame=getFrame()).mtv(exposure, title="Fringe subtracted")
182 return solution, rms
183
◆ solve()
| lsst.ip.isr.fringe.FringeTask.solve | ( | self, | |
| science, | |||
| fringes ) |
Solve for the scale factors with iterative clipping.
Parameters
----------
science : `numpy.array`
Array of measured science image values at each of the
positions supplied.
fringes : `numpy.array`
Array of measured fringe values at each of the positions
supplied.
Returns
-------
solution : `np.array`
Fringe solution amplitudes for each input fringe frame.
rms : `float`
RMS error for the fit solution for this exposure.
Definition at line 293 of file fringe.py.
293 def solve(self, science, fringes):
294 """Solve for the scale factors with iterative clipping.
295
296 Parameters
297 ----------
298 science : `numpy.array`
299 Array of measured science image values at each of the
300 positions supplied.
301 fringes : `numpy.array`
302 Array of measured fringe values at each of the positions
303 supplied.
304
305 Returns
306 -------
307 solution : `np.array`
308 Fringe solution amplitudes for each input fringe frame.
309 rms : `float`
310 RMS error for the fit solution for this exposure.
311 """
312 import lsstDebug
313 doPlot = lsstDebug.Info(__name__).plot
314
315 origNum = len(science)
316
317 def emptyResult(msg=""):
318 """Generate an empty result for return to the user
319
320 There are no good pixels; doesn't matter what we return.
321 """
322 self.log.warning("Unable to solve for fringes: no good pixels%s", msg)
323 out = [0]
324 if len(fringes) > 1:
325 out = out*len(fringes)
326 return numpy.array(out), numpy.nan
327
328 good = numpy.where(numpy.logical_and(numpy.isfinite(science), numpy.any(numpy.isfinite(fringes), 1)))
329 science = science[good]
330 fringes = fringes[good]
331 oldNum = len(science)
332 if oldNum == 0:
333 return emptyResult()
334
335 # Up-front rejection to get rid of extreme, potentially troublesome
336 # values (e.g., fringe apertures that fall on objects).
337 good = select(science, self.config.clip)
338 for ff in range(fringes.shape[1]):
339 good &= select(fringes[:, ff], self.config.clip)
340 science = science[good]
341 fringes = fringes[good]
342 oldNum = len(science)
343 if oldNum == 0:
344 return emptyResult(" after initial rejection")
345
346 for i in range(self.config.iterations):
347 solution = self._solve(science, fringes)
348 resid = science - numpy.sum(solution*fringes, 1)
349 rms = stdev(resid)
350 good = numpy.logical_not(abs(resid) > self.config.clip*rms)
351 self.log.debug("Iteration %d: RMS=%f numGood=%d", i, rms, good.sum())
352 self.log.debug("Solution %d: %s", i, solution)
353 newNum = good.sum()
354 if newNum == 0:
355 return emptyResult(" after %d rejection iterations" % i)
356
357 if doPlot:
358 import matplotlib.pyplot as plot
359 for j in range(fringes.shape[1]):
360 fig = plot.figure(j)
361 fig.clf()
362 try:
363 fig.canvas._tkcanvas._root().lift() # == Tk's raise
364 except Exception:
365 pass
366 ax = fig.add_subplot(1, 1, 1)
367 adjust = science.copy()
368 others = set(range(fringes.shape[1]))
369 others.discard(j)
370 for k in others:
371 adjust -= solution[k]*fringes[:, k]
372 ax.plot(fringes[:, j], adjust, 'r.')
373 xmin = fringes[:, j].min()
374 xmax = fringes[:, j].max()
375 ymin = solution[j]*xmin
376 ymax = solution[j]*xmax
377 ax.plot([xmin, xmax], [ymin, ymax], 'b-')
378 ax.set_title("Fringe %d: %f" % (j, solution[j]))
379 ax.set_xlabel("Fringe amplitude")
380 ax.set_ylabel("Science amplitude")
381 ax.set_autoscale_on(False)
382 ax.set_xbound(lower=xmin, upper=xmax)
383 ax.set_ybound(lower=ymin, upper=ymax)
384 fig.show()
385 while True:
386 ans = input("Enter or c to continue [chp]").lower()
387 if ans in ("", "c",):
388 break
389 if ans in ("p",):
390 import pdb
391 pdb.set_trace()
392 elif ans in ("h", ):
393 print("h[elp] c[ontinue] p[db]")
394
395 if newNum == oldNum:
396 # Not gaining
397 break
398 oldNum = newNum
399 good = numpy.where(good)
400 science = science[good]
401 fringes = fringes[good]
402
403 # Final solution without rejection
404 solution = self._solve(science, fringes)
405 self.log.info("Fringe solution: %s RMS: %f Good: %d/%d", solution, rms, len(science), origNum)
406 return solution, rms
407
◆ subtract()
| lsst.ip.isr.fringe.FringeTask.subtract | ( | self, | |
| science, | |||
| fringes, | |||
| solution ) |
Subtract the fringes.
Parameters
----------
science : `lsst.afw.image.Exposure`
Science exposure from which to remove fringes.
fringes : `lsst.afw.image.Exposure` or `list` thereof
Calibration fringe files containing master fringe frames.
solution : `np.array`
Fringe solution amplitudes for each input fringe frame.
Raises
------
RuntimeError
Raised if the number of fringe frames does not match the
number of measured amplitudes.
Definition at line 428 of file fringe.py.
428 def subtract(self, science, fringes, solution):
429 """Subtract the fringes.
430
431 Parameters
432 ----------
433 science : `lsst.afw.image.Exposure`
434 Science exposure from which to remove fringes.
435 fringes : `lsst.afw.image.Exposure` or `list` thereof
436 Calibration fringe files containing master fringe frames.
437 solution : `np.array`
438 Fringe solution amplitudes for each input fringe frame.
439
440 Raises
441 ------
442 RuntimeError
443 Raised if the number of fringe frames does not match the
444 number of measured amplitudes.
445 """
446 if len(solution) != len(fringes):
447 raise RuntimeError("Number of fringe frames (%s) != number of scale factors (%s)" %
448 (len(fringes), len(solution)))
449
450 for s, f in zip(solution, fringes):
451 # We do not want to add the mask from the fringe to the image.
452 f.getMaskedImage().getMask().getArray()[:] = 0
453 science.getMaskedImage().scaledMinus(s, f.getMaskedImage())
454
455
Member Data Documentation
◆ _DefaultName
|
staticprotected |
◆ ConfigClass
|
static |
The documentation for this class was generated from the following file:
- /j/snowflake/release/lsstsw/stack/lsst-scipipe-12.1.0/Linux/ip_isr/gc24b5d6ed1+9f17e571f4/python/lsst/ip/isr/fringe.py
Generated on Thu Nov 27 2025 09:15:13 for LSST Applications by
1.13.2