Coverage for python / lsst / drp / tasks / tract_background.py: 0%
199 statements
« prev ^ index » next coverage.py v7.13.5, created at 2026-05-04 17:41 +0000
1# This file is part of drp_tasks.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (https://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This program is free software: you can redistribute it and/or modify
10# it under the terms of the GNU General Public License as published by
11# the Free Software Foundation, either version 3 of the License, or
12# (at your option) any later version.
13#
14# This program is distributed in the hope that it will be useful,
15# but WITHOUT ANY WARRANTY; without even the implied warranty of
16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17# GNU General Public License for more details.
18#
19# You should have received a copy of the GNU General Public License
20# along with this program. If not, see <https://www.gnu.org/licenses/>.
22from __future__ import annotations
24__all__ = (
25 "BinnedTractGeometry",
26 "MeasureTractBackgroundConfig",
27 "MeasureTractBackgroundConnections",
28 "MeasureTractBackgroundTask",
29 "SubtractTractBackgroundConfig",
30 "SubtractTractBackgroundConnections",
31 "SubtractTractBackgroundTask",
32)
34import dataclasses
35from collections.abc import Iterable, Mapping
36from typing import ClassVar
38import numpy as np
40from lsst.afw.geom import SkyWcs, SpanSet, makeModifiedWcs, makeTransform
41from lsst.afw.image import ExposureF, FilterLabel, MaskX
42from lsst.afw.math import (
43 BackgroundList,
44 binImage,
45)
46from lsst.geom import AffineTransform, Box2I, Extent2I, LinearTransform, Point2I
47from lsst.meas.algorithms import SubtractBackgroundTask
48from lsst.pex.config import ConfigurableField, Field, ListField
49from lsst.pipe.base import (
50 InputQuantizedConnection,
51 OutputQuantizedConnection,
52 PipelineTask,
53 PipelineTaskConfig,
54 PipelineTaskConnections,
55 QuantumContext,
56 Struct,
57)
58from lsst.pipe.base import connectionTypes as cT
59from lsst.skymap import BaseSkyMap, TractInfo
62@dataclasses.dataclass
63class BinnedTractGeometry:
64 """Geometry for binned tract-level images."""
66 tract_info: TractInfo
67 """Definition of the tract."""
69 original_bbox: Box2I
70 """The original bounding box of the tract level image in true pixel
71 coordinates.
73 Since this is constructed from a union of patch-level bounding boxes that
74 are in general between the patch inner and outer boundin boxes, it is not
75 the same as the tract's usual bounding box.
76 """
78 superpixel_size: Extent2I
79 """The number of true pixels in each superpixel in each dimension."""
81 binned_bbox: Box2I
82 """The bounding box of the tract-level image in superpixel coordinates."""
84 binned_wcs: SkyWcs
85 """A WCS that maps the superpixel image to the sky."""
87 def slices(self, child_bbox: Box2I) -> tuple[slice, slice]:
88 """Return the array slices that select the given pixel-coordinate
89 bounding box within the superpixel tract image.
91 Parameters
92 ----------
93 child_bbox : `lsst.geom.Box2I`
94 True-pixel bounding box to select.
96 Returns
97 -------
98 y_slice : `slice`
99 Superpixel image slice in the y dimension.
100 x_slice : `slice`
101 Superpixel image slice in the x dimension.
102 """
103 assert child_bbox.y.begin % self.superpixel_size.y == 0, "superpixel size evenly divides bboxes"
104 assert child_bbox.x.begin % self.superpixel_size.x == 0, "superpixel size evenly divides bboxes"
105 assert child_bbox.y.end % self.superpixel_size.y == 0, "superpixel size evenly divides bboxes"
106 assert child_bbox.x.end % self.superpixel_size.x == 0, "superpixel size evenly divides bboxes"
107 return (
108 slice(
109 (child_bbox.y.begin - self.original_bbox.y.begin) // self.superpixel_size.y,
110 (child_bbox.y.end - self.original_bbox.y.begin) // self.superpixel_size.y,
111 ),
112 slice(
113 (child_bbox.x.begin - self.original_bbox.x.begin) // self.superpixel_size.x,
114 (child_bbox.x.end - self.original_bbox.x.begin) // self.superpixel_size.x,
115 ),
116 )
119class MeasureTractBackgroundConnections(PipelineTaskConnections, dimensions=["tract"]):
120 sky_map = cT.Input(
121 doc="Input definition of geometry/bbox and projection/wcs for warps.",
122 name=BaseSkyMap.SKYMAP_DATASET_TYPE_NAME,
123 storageClass="SkyMap",
124 dimensions=("skymap",),
125 )
126 hf_backgrounds = cT.Input(
127 "deep_coadd_hf_background",
128 doc=(
129 "Original high-frequency background. Bins must exactly divide the inner patch region. "
130 "This input can be produced by running DetectCoaddSourcesTask with forceExactBinning "
131 "and writeEmptyBackgrounds both set to True."
132 ""
133 ),
134 storageClass="Background",
135 multiple=True,
136 dimensions=["patch", "band"],
137 )
138 lf_backgrounds = cT.Output(
139 "deep_coadd_lf_background",
140 doc=(
141 "Remeasured low-frequency background, covering the same patches and area within those patches "
142 "as the input high-frequency backgrounds."
143 ),
144 storageClass="Background",
145 multiple=True,
146 dimensions=["patch", "band"],
147 )
148 hf_diagnostic_images = cT.Output(
149 "deep_coadd_hf_background_image",
150 doc="Tract-level image of the original high-frequency background superpixels.",
151 storageClass="ExposureF",
152 multiple=True,
153 dimensions=["tract", "band"],
154 )
155 lf_diagnostic_images = cT.Output(
156 "deep_coadd_lf_background_image",
157 doc="Tract-level image of the remeasured low-frequency background superpixels.",
158 storageClass="ExposureF",
159 multiple=True,
160 dimensions=["tract", "band"],
161 )
163 def __init__(self, *, config=None):
164 assert isinstance(config, MeasureTractBackgroundConfig)
165 if not config.write_diagnostic_images:
166 del self.hf_diagnostic_images
167 del self.lf_diagnostic_images
169 def adjustQuantum(self, inputs, outputs, label, data_id):
170 # Make sure we have an input for every output, and vice-versa.
171 hf_connection, hf_refs = inputs["hf_backgrounds"]
172 lf_connection, lf_refs = outputs["lf_backgrounds"]
173 hf_refs_by_data_id = {ref.dataId: ref for ref in hf_refs}
174 lf_refs_by_data_id = {ref.dataId: ref for ref in lf_refs}
175 common = sorted(hf_refs_by_data_id.keys() & lf_refs_by_data_id.keys())
176 inputs["hf_backgrounds"] = (hf_connection, [hf_refs_by_data_id[d] for d in common])
177 outputs["lf_backgrounds"] = (lf_connection, [lf_refs_by_data_id[d] for d in common])
178 return super().adjustQuantum(inputs, outputs, label, data_id)
181class MeasureTractBackgroundConfig(PipelineTaskConfig, pipelineConnections=MeasureTractBackgroundConnections):
182 background = ConfigurableField(
183 "Configuration for the task used to subtract the background on the tract-level "
184 "image of superpixels. The bin sizes in this configuration are in superpixel units, "
185 "and the interpolation/approximation parameter control how the superpixel background is "
186 "interpolated back onto the input high-frequency background bins. ",
187 target=SubtractBackgroundTask,
188 )
189 mask_grow_input_planes = ListField(
190 "Mask planes to union across bands, grow by 'mask_grow_radius', and set as "
191 "'mask_grow_output_plane'. Superpixel values that are NaN are masked as NO_DATA before this "
192 "operation.",
193 dtype=str,
194 default=["NO_DATA"],
195 )
196 mask_grow_radius = Field(
197 "Radius to grow the background subtraction mask by (in tract-level superpixels, "
198 "i.e. bins used in the high-frequency backgrounds).",
199 dtype=int,
200 default=8,
201 )
202 mask_grow_output_plane = Field(
203 "Name of the mask plane that will hold the grown union of 'mask_grow_input_planes'.",
204 dtype=str,
205 default="BG_IGNORE",
206 )
207 write_diagnostic_images = Field(
208 "Whether to write diagnostic image outputs.",
209 dtype=bool,
210 default=True,
211 )
213 def setDefaults(self):
214 super().setDefaults()
215 self.background.binSize = 8
216 self.background.useApprox = False
217 self.background.ignoredPixelMask.append("BG_IGNORE")
219 def validate(self):
220 super().validate()
221 if self.mask_grow_output_plane not in self.background.ignoredPixelMask:
222 raise ValueError(
223 f"mask_grow_output_plane={self.mask_grow_output_plane} "
224 "is not used in 'background.ignoredMaskPixels'."
225 )
228class MeasureTractBackgroundTask(PipelineTask):
229 """A task that fits a (relatively) low-frequency background to tract-level
230 superpixels, using high-frequency patch-level backgrounds as inputs.
232 Notes
233 -----
234 This task starts from an initial round of high-frequency background
235 estimation done in a previous task (e.g. DetectCoaddSourcesTask), combining
236 the per-bin background estimates into a tract-level image in which each
237 superpixel corresponds to a single bin from an input background object.
238 The input background's configuration for how to interpolate or approximate
239 those bin values is ignored at this stage; we use backgrounds as inputs
240 rather than simple binned images because each background bin value is
241 already a robust mean of non-detected pixels, which does a passable job
242 at avoiding contamination from sources.
244 For tracts with very large objects, it is expected that the tract-level
245 image will have many missing superpixels (i.e. with NaN values). These
246 are used to form a mask, which is then unioned across all bands and grown
247 by a configurable amount. That mask is then input to a round of background
248 subtraction on the superpixel image to form the "low frequency" output
249 background models. This background is propagated to patch-level output
250 `lsst.afw.math.BackgroundList` objects by replacing the bin values in the
251 input objects with the interpolated low-frequency model. The original
252 input interpolation/approximation configuration is then used in the
253 outputs.
255 This task runs over multiple bands at once only to enable that cross-band
256 union of masks, which is nevertheless very important (at least in the
257 context of making RGB images from the background-subtracted coadds, but
258 avoiding unphysical colors is good for science productions, too).
259 """
261 _DefaultName: ClassVar[str] = "measureTractBackground"
262 ConfigClass: ClassVar[type[MeasureTractBackgroundConfig]] = MeasureTractBackgroundConfig
263 config: MeasureTractBackgroundConfig
265 def __init__(self, *, config=None, log=None, initInputs=None, **kwargs):
266 super().__init__(config=config, log=log, initInputs=initInputs, **kwargs)
267 self.makeSubtask("background")
269 def runQuantum(
270 self,
271 butlerQC: QuantumContext,
272 inputRefs: InputQuantizedConnection,
273 outputRefs: OutputQuantizedConnection,
274 ):
275 sky_map = butlerQC.get(inputRefs.sky_map)
276 tract_info = sky_map[butlerQC.quantum.dataId["tract"]]
277 hf_backgrounds = {
278 (ref.dataId["band"], ref.dataId["patch"]): butlerQC.get(ref) for ref in inputRefs.hf_backgrounds
279 }
280 results = self.run(hf_backgrounds=hf_backgrounds, tract_info=tract_info)
281 for ref in outputRefs.lf_backgrounds:
282 butlerQC.put(results.lf_backgrounds[ref.dataId["band"], ref.dataId["patch"]], ref)
283 if self.config.write_diagnostic_images:
284 for ref in outputRefs.hf_diagnostic_images:
285 butlerQC.put(results.hf_diagnostic_images[ref.dataId["band"]], ref)
286 for ref in outputRefs.lf_diagnostic_images:
287 butlerQC.put(results.lf_diagnostic_images[ref.dataId["band"]], ref)
289 def run(
290 self, *, hf_backgrounds: Mapping[tuple[str, int], BackgroundList], tract_info: TractInfo
291 ) -> Struct:
292 """Estimate a tract-level background model.
294 Parameters
295 ----------
296 hf_backgrounds : `~collections.abc.Mapping`
297 Mapping of input `lsst.afw.math.BackgroundList` instances, keyed
298 by tuples of ``(band, patch)``. Each background must have a single
299 layer with bins that exactly divide the patch inner region (but may
300 have bins of the same size outside the patch inner region).
301 tract_info : `lsst.skymap.TractInfo`
302 Geometry information for the tract.
304 Returns
305 -------
306 results : `lsst.pipe.base.Struct`
307 Results struct with the following attributes:
309 - ``lf_backgrounds``: mapping of output
310 `lsst.afw.math.BackgroundList` instances, with the same keys as
311 ``hf_backgrounds``.
312 - ``hf_diagnostic_images``: mapping of tract-level superpixel
313 images with the input backgrounds, keyed by band.
314 - ``lf_diagnostic_images``: mapping of tract-level superpixel
315 images with the output backgrounds, keyed by band.
316 - ``geometry``: `BinnedTractGeometry`: struct with the geometry
317 of the bins.
318 """
319 geometry = self.compute_geometry(hf_backgrounds=hf_backgrounds.values(), tract_info=tract_info)
320 hf_bg_exposures = self.make_hf_background_exposures(geometry=geometry, hf_backgrounds=hf_backgrounds)
321 common_mask = MaskX(geometry.binned_bbox)
322 for hf_bg_exposure in hf_bg_exposures.values():
323 common_mask |= hf_bg_exposure.mask
324 grow_spans = (
325 SpanSet.fromMask(common_mask, common_mask.getPlaneBitMask(self.config.mask_grow_input_planes))
326 .dilated(self.config.mask_grow_radius)
327 .clippedTo(geometry.binned_bbox)
328 )
329 grow_spans.setMask(common_mask, common_mask.getPlaneBitMask(self.config.mask_grow_output_plane))
330 lf_bg_exposures = {}
331 for band, hf_bg_exposure in hf_bg_exposures.items():
332 hf_bg_exposure.mask = common_mask
333 lf_bg_list = self.background.run(hf_bg_exposure).background
334 lf_bg_exposure = hf_bg_exposure.clone()
335 lf_bg_exposure.image = lf_bg_list.getImage()
336 lf_bg_exposures[band] = lf_bg_exposure
337 lf_backgrounds = self.make_lf_background_lists(
338 lf_bg_exposures=lf_bg_exposures, geometry=geometry, hf_backgrounds=hf_backgrounds
339 )
340 return Struct(
341 lf_backgrounds=lf_backgrounds,
342 hf_diagnostic_images=hf_bg_exposures,
343 lf_diagnostic_images=lf_bg_exposures,
344 geometry=geometry,
345 )
347 def compute_geometry(
348 self, *, hf_backgrounds: Iterable[BackgroundList], tract_info: TractInfo
349 ) -> BinnedTractGeometry:
350 """Work out the geometry of a binned tract-level superpixel image.
352 Parameters
353 ----------
354 hf_backgrounds : `~collections.abc.Iterable`
355 Iterable of all input `lsst.afw.math.BackgroundList` instances that
356 cover the tract.
357 tract_info : `lsst.skymap.TractInfo`
358 Geometry information for the tract.
360 Returns
361 -------
362 geometry: `BinnedTractGeometry`
363 A struct describing the bounding boxes and binning of the
364 tract-level superpixel image.
365 """
366 original_bbox = Box2I()
367 superpixel_size: Extent2I | None = None
368 for hf_bg_list in hf_backgrounds:
369 patch_bbox: Box2I | None = None
370 for hf_bg, *_ in hf_bg_list:
371 if patch_bbox is None:
372 patch_bbox = hf_bg.getImageBBox()
373 else:
374 assert patch_bbox == hf_bg.getImageBBox()
375 stats_image_bbox = hf_bg.getStatsImage().getBBox()
376 if superpixel_size is None:
377 superpixel_size = Extent2I(
378 patch_bbox.width // stats_image_bbox.width,
379 patch_bbox.height // stats_image_bbox.height,
380 )
381 assert superpixel_size.x * stats_image_bbox.width == patch_bbox.width
382 assert superpixel_size.y * stats_image_bbox.height == patch_bbox.height
383 original_bbox.include(patch_bbox)
384 binned_bbox = Box2I(
385 Point2I(original_bbox.x.begin // superpixel_size.x, original_bbox.y.begin // superpixel_size.y),
386 Extent2I(original_bbox.width // superpixel_size.x, original_bbox.height // superpixel_size.y),
387 )
388 return BinnedTractGeometry(
389 tract_info=tract_info,
390 original_bbox=original_bbox,
391 superpixel_size=superpixel_size,
392 binned_bbox=binned_bbox,
393 binned_wcs=_make_binned_wcs(tract_info.getWcs(), superpixel_size.x, superpixel_size.y),
394 )
396 def make_hf_background_exposures(
397 self, *, geometry: BinnedTractGeometry, hf_backgrounds: Mapping[tuple[str, int], BackgroundList]
398 ) -> dict[str, ExposureF]:
399 """Build tract-level superpixel images from the bin values in input
400 backgrounds.
402 Parameters
403 ----------
404 hf_backgrounds : `~collections.abc.Mapping`
405 Mapping of input `lsst.afw.math.BackgroundList` instances, keyed
406 by tuples of ``(band, patch)``. Each background must have a single
407 layer with bins that exactly divide the patch inner region (but may
408 have bins of the same size outside the patch inner region).
409 geometry: `BinnedTractGeometry`
410 A struct describing the bounding boxes and binning of the
411 tract-level superpixel image.
413 Returns
414 -------
415 hf_images : `dict`
416 Mapping of tract-level superpixel images
417 (`lsst.afw.image.ExposureF` objects) with the input background bin
418 values, keyed by band.
419 """
420 result = {}
421 no_data_bitmask = MaskX.getPlaneBitMask("NO_DATA")
422 for (band, _), hf_bg_list in hf_backgrounds.items():
423 if (exposure := result.get(band)) is None:
424 exposure = ExposureF(geometry.binned_bbox)
425 exposure.setWcs(geometry.binned_wcs)
426 exposure.setFilter(FilterLabel.fromBand(band))
427 exposure.image.array[...] = np.nan
428 exposure.mask.array[...] = no_data_bitmask
429 exposure.variance.array[...] = 0.0
430 exposure.mask.addMaskPlane(self.config.mask_grow_output_plane)
431 result[band] = exposure
432 if len(hf_bg_list) != 1:
433 raise RuntimeError("Input BackgroundList must have exactly one layer.")
434 hf_bg = hf_bg_list[0][0]
435 tract_slices = geometry.slices(hf_bg.getImageBBox())
436 stats_image = hf_bg.getStatsImage()
437 exposure.image.array[tract_slices] = stats_image.image.array
438 exposure.mask.array[tract_slices] = stats_image.mask.array
439 exposure.mask.array[tract_slices] |= no_data_bitmask * np.isnan(stats_image.image.array)
440 exposure.variance.array[tract_slices] = stats_image.variance.array
441 return result
443 def make_lf_background_lists(
444 self,
445 *,
446 lf_bg_exposures: Mapping[str, ExposureF],
447 geometry: BinnedTractGeometry,
448 hf_backgrounds: Mapping[tuple[str, int], BackgroundList],
449 ) -> dict[tuple[str, int], BackgroundList]:
450 """Make output `lsst.afw.math.BackgroundList` objects for each patch
451 and band.
453 Parameters
454 ----------
455 lf_bg_exposures : `~collections.abc.Mapping`
456 Mapping from band to binned tract-level superpixel images
457 (`lsst.afw.image.ExposureF` instance) that hold the low-frequency
458 background model fit to the tract-level superpixel image for that
459 band.
460 geometry: `BinnedTractGeometry`
461 A struct describing the bounding boxes and binning of the
462 tract-level superpixel image.
463 hf_backgrounds : `~collections.abc.Mapping`
464 Mapping of input `lsst.afw.math.BackgroundList` instances, keyed
465 by tuples of ``(band, patch)``. THESE ARE MODIFIED IN PLACE AND
466 SHOULD BE CONSIDERED CONSUMED.
468 Returns
469 -------
470 lf_backgrounds : `dict`
471 A dictionary of output low-frequency `lsst.afw.math.BackgroundList`
472 instances, keyed by tuples of ``(band, patch)``. These use the
473 same interpolation/approximation parameters as the input
474 high-frequency background objects, but have their bin values
475 replaced by evaluating the low-frequency background model for the
476 tract.
477 """
478 result = {}
479 for (band, patch_id), hf_bg_list in hf_backgrounds.items():
480 lf_bg_list = BackgroundList()
481 lf_bg_list.append(hf_bg_list[0])
482 lf_bg, *_ = lf_bg_list[0]
483 stats_image = lf_bg.getStatsImage()
484 slices = geometry.slices(lf_bg.getImageBBox())
485 stats_image.image.array[...] = lf_bg_exposures[band].image.array[slices]
486 stats_image.mask.array[...] = 0
487 stats_image.variance.array[...] = 1.0
488 result[band, patch_id] = lf_bg_list
489 return result
492class SubtractTractBackgroundConnections(PipelineTaskConnections, dimensions=["patch", "band"]):
493 input_coadd = cT.Input(
494 "deep_coadd_predetection",
495 doc="Original coadd with only large-scale visit-level background subtraction.",
496 storageClass="ExposureF",
497 dimensions=["patch", "band"],
498 )
499 lf_background = cT.Input(
500 "deep_coadd_lf_background",
501 doc="Remeasured low-frequency background, covering inner patch regions only.",
502 storageClass="Background",
503 dimensions=["patch", "band"],
504 )
505 output_coadd = cT.Output(
506 "deep_coadd_lf_subtracted",
507 doc="Output coadd with tract-level backgrounds subtracted.",
508 storageClass="ExposureF",
509 dimensions=["patch", "band"],
510 )
511 input_coadd_binned = cT.Output(
512 "deep_coadd_predetection_binned",
513 doc="Binned version of 'input_coadd`, with bin size set to the superpixel size.",
514 storageClass="ExposureF",
515 dimensions=["patch", "band"],
516 )
517 output_coadd_binned = cT.Output(
518 "deep_coadd_lf_subtracted_binned",
519 doc="Binned version of 'output_coadd`, with bin size set to the superpixel size.",
520 storageClass="ExposureF",
521 dimensions=["patch", "band"],
522 )
524 def __init__(self, *, config=None):
525 assert isinstance(config, SubtractTractBackgroundConfig)
526 if not config.write_binned_images:
527 del self.input_coadd_binned
528 del self.output_coadd_binned
531class SubtractTractBackgroundConfig(
532 PipelineTaskConfig, pipelineConnections=SubtractTractBackgroundConnections
533):
534 write_binned_images = Field(
535 "Whether to write out a binned versions of the input and output coadds.",
536 dtype=bool,
537 default=True,
538 )
541class SubtractTractBackgroundTask(PipelineTask):
542 """A task that subtracts a previously-fit background model from a coadd.
544 Notes
545 -----
546 This task is designed to apply the background models fit by
547 `MeasureTractBackgroundTask`. It also produces diagnostic outputs that are
548 useful for developing and configuring that task.
549 """
551 _DefaultName: ClassVar[str] = "subtractTractBackground"
552 ConfigClass: ClassVar[type[SubtractTractBackgroundConfig]] = SubtractTractBackgroundConfig
553 config: SubtractTractBackgroundConfig
555 def run(self, *, input_coadd: ExposureF, lf_background: BackgroundList) -> Struct:
556 """Subtract a background model from a coadd and optionally write
557 binned versions of the original and background-subtracted images.
559 Parameters
560 ----------
561 input_coadd : `lsst.afw.image.ExposureF`
562 Input coadd to subtract a background from.
563 lf_background : `lsst.afw.math.BackgroundList`
564 Background model to subtract. May only cover a subset of the given
565 coadd.
567 Returns
568 -------
569 results : `lsst.pipe.base.Struct`
570 Output struct containing:
572 - ``output_coadd`` (`lsst.afw.image.ExposureF`):
573 The output background-subtracted coadd. If ``lf_background``
574 only covers a subset of ``input_coadd``, this will be cropped
575 to just that subset.
576 - ``input_coadd_binned`` (``lsst.afw.image.ExposureF``):
577 A binned version of the input coadd. Only produced if
578 `~SubtractTractBackgroundConfig.write_binned_images` is `True`.
579 - ``output_coadd_binned`` (``lsst.afw.image.ExposureF``):
580 A binned version of the output coadd. Only produced if
581 `~SubtractTractBackgroundConfig.write_binned_images` is `True`.
582 """
583 for bg, *_ in lf_background:
584 bg_bbox = bg.getImageBBox()
585 bg_binned_bbox = bg.getStatsImage().getBBox()
586 bin_size_x = bg_bbox.width // bg_binned_bbox.width
587 bin_size_y = bg_bbox.height // bg_binned_bbox.height
588 break
589 else:
590 raise AssertionError("No background in background list.")
591 input_coadd = input_coadd[bg_bbox]
592 result = Struct()
593 if self.config.write_binned_images:
594 result.input_coadd_binned = ExposureF(binImage(input_coadd.maskedImage, bin_size_x, bin_size_y))
595 result.input_coadd_binned.setXY0(
596 Point2I(input_coadd.getX0() // bin_size_x, input_coadd.getY0() // bin_size_y)
597 )
598 result.input_coadd_binned.setWcs(_make_binned_wcs(input_coadd.getWcs(), bin_size_x, bin_size_y))
599 result.input_coadd_binned.setFilter(input_coadd.getFilter())
600 bg_image = lf_background.getImage()
601 result.output_coadd = input_coadd.clone()
602 result.output_coadd.image -= bg_image
603 if self.config.write_binned_images:
604 result.output_coadd_binned = result.input_coadd_binned.clone()
605 result.output_coadd_binned.image = binImage(result.output_coadd.image, bin_size_x, bin_size_y)
606 return result
609def _make_binned_wcs(original: SkyWcs, bin_size_x: int, bin_size_y: int) -> SkyWcs:
610 """Make a WCS appropriate for a binned version of an image.
612 Parameters
613 ----------
614 original : `lsst.afw.geom.SkyWcs`
615 Original WCS for the unbinned image.
616 bin_size_x : `int`
617 Size of each bin in the X dimension.
618 bin_size_y : `int`
619 Size of each bin in the Y dimension.
621 Returns
622 -------
623 binned_wcs : `lsst.afw.geom.SkyWcs`
624 WCS for the binned image.
626 Notes
627 -----
628 This function assumes that the original image's XY0 has been divided by
629 the bin size in each dimension (or is ``(0, 0)`` so this is irrelevant).
630 """
631 binned_to_original = makeTransform(AffineTransform(LinearTransform.makeScaling(bin_size_x, bin_size_y)))
632 return makeModifiedWcs(binned_to_original, original, False)