Assemble a coadded image from a set of coadded temporary exposures. More...
Public Member Functions | |
def | __init__ |
Initialize the task. More... | |
def | run |
Assemble a coadd from a set of coaddTempExp. More... | |
def | getTempExpRefList |
Generate list of coaddTempExp data references corresponding to exposures that lie within the patch to be coadded. More... | |
def | getBackgroundReferenceScaler |
Construct an image scaler for the background reference frame. More... | |
def | prepareInputs |
Prepare the input warps for coaddition by measuring the weight for each warp and the scaling for the photometric zero point. More... | |
def | backgroundMatching |
Perform background matching on the prepared inputs. More... | |
def | assemble |
Assemble a coadd from input warps. More... | |
def | assembleMetadata |
Set the metadata for the coadd. More... | |
def | assembleSubregion |
Assemble the coadd for a sub-region. More... | |
def | addBackgroundMatchingMetadata |
Add metadata from the background matching to the coadd. More... | |
def | readBrightObjectMasks |
def | setBrightObjectMasks |
Public Attributes | |
brightObjectBitmask | |
Static Public Attributes | |
ConfigClass = AssembleCoaddConfig | |
Assemble a coadded image from a set of coadded temporary exposures.
We want to assemble a coadded image from a set of coadded temporary exposures (coaddTempExps). Each input coaddTempExp covers a patch on the sky and corresponds to a single run/visit/exposure of the covered patch. We provide the task with a list of coaddTempExps (selectDataList) from which it selects coaddTempExps that cover the specified patch (pointed at by dataRef). Each coaddTempExp that goes into a coadd will typically have an independent photometric zero-point. Therefore, we must scale each coaddTempExp to set it to a common photometric zeropoint. By default, each coaddTempExp has backgrounds and hence will require config.doMatchBackgrounds=True. When background matching is enabled, the task may be configured to automatically select a reference exposure (config.autoReference=True). If this is not done, we require that the input dataRef provides access to a coaddTempExp (dataset type coaddName + 'Coadd_tempExp') which is used as the reference exposure. The coadd is computed as a mean with optional outlier rejection. Criteria for outlier rejection are set in AssembleCoaddConfig. Finally, coaddTempExps can have bad 'NaN' pixels which received no input from the source calExps. We interpolate over these bad (NaN) pixels.
AssembleCoaddTask uses several sub-tasks. These are
You can retarget these subtasks if you wish.
Initialize the task. Create the interpImage, matchBackgrounds, & scaleZeroPoint subtasks.
Assemble a coadd from a set of coaddTempExp. Coadd a set of coaddTempExps. Compute weights to be applied to each coaddTempExp and find scalings to match the photometric zeropoint to a reference coaddTempExp. Optionally, match backgrounds across coaddTempExps if the background has not already been removed. Assemble the coaddTempExps using assemble. Interpolate over NaNs and optionally write the coadd to disk. Return the coadded exposure.
[in] | dataRef,: | Data reference defining the patch for coaddition and the reference coaddTempExp (if config.autoReference=False). Used to access the following data products:
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[in] | selectDataList[in],: | List of data references to coaddTempExps. Data to be coadded will be selected from this list based on overlap with the patch defined by dataRef. |
The command line task interface supports a flag -d
to import debug.py from your PYTHONPATH
; see baseDebug for more about debug.py files. AssembleCoaddTask has no debug variables of its own. Some of the subtasks may support debug variables. See the documetation for the subtasks for further information.
AssembleCoaddTask assembles a set of warped coaddTempExp images into a coadded image. The AssembleCoaddTask can be invoked by running assembleCoadd.py with the flag '–legacyCoadd'. Usage of assembleCoadd.py expects a data reference to the tract patch and filter to be coadded (specified using '–id = [KEY=VALUE1[^VALUE2[^VALUE3...] [KEY=VALUE1[^VALUE2[^VALUE3...] ...]]') along with a list of coaddTempExps to attempt to coadd (specified using '–selectId [KEY=VALUE1[^VALUE2[^VALUE3...] [KEY=VALUE1[^VALUE2[^VALUE3...] ...]]'). Only the coaddTempExps that cover the specified tract and patch will be coadded. A list of the available optional arguments can be obtained by calling assembleCoadd.py with the –help command line argument:
To demonstrate usage of the AssembleCoaddTask in the larger context of multi-band processing, we will generate the HSC-I & -R band coadds from HSC engineering test data provided in the ci_hsc package. To begin, assuming that the lsst stack has been already set up, we must set up the obs_subaru and ci_hsc packages. This defines the environment variable $CI_HSC_DIR and points at the location of the package. The raw HSC data live in the $CI_HSC_DIR/raw directory. To begin assembling the coadds, we must first
We can perform all of these steps by running
This will produce warped coaddTempExps for each visit. To coadd the warped data, we call assembleCoadd.py as follows:
that will process the HSC-I band data. The results are written in $CI_HSC_DIR/DATA/deepCoadd-results/HSC-I You may also choose to run:
to generate the coadd for the HSC-R band if you are interested in following multiBand Coadd processing as discussed in High-level Overview of Multi-Band Coadd Processing (but note that normally, one would use the SafeClipAssembleCoaddTask rather than AssembleCoaddTask to make the coadd.
Definition at line 156 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.__init__ | ( | self, | |
args, | |||
kwargs | |||
) |
Initialize the task.
Create the interpImage, matchBackgrounds, & scaleZeroPoint subtasks.
Definition at line 262 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.addBackgroundMatchingMetadata | ( | self, | |
coaddExposure, | |||
tempExpRefList, | |||
backgroundInfoList | |||
) |
Add metadata from the background matching to the coadd.
[in] | coaddExposure,: | Coadd |
[in] | tempExpRefList,: | List of data references for temp exps to go into coadd |
[in] | backgroundInfoList,: | List of background info, results from background matching |
Definition at line 697 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.assemble | ( | self, | |
skyInfo, | |||
tempExpRefList, | |||
imageScalerList, | |||
weightList, | |||
bgInfoList = None , |
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altMaskList = None , |
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doClip = False , |
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mask = None |
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) |
Assemble a coadd from input warps.
Assemble the coadd using the provided list of coaddTempExps. Since the full coadd covers a patch (a large area), the assembly is performed over small areas on the image at a time in order to conserve memory usage. Iterate over subregions within the outer bbox of the patch using assembleSubregion to mean-stack the corresponding subregions from the coaddTempExps (with outlier rejection if config.doSigmaClip=True). Set the edge bits the the coadd mask based on the weight map.
[in] | skyInfo,: | Patch geometry information, from getSkyInfo |
[in] | tempExpRefList,: | List of data references to tempExp |
[in] | imageScalerList,: | List of image scalers |
[in] | weightList,: | List of weights |
[in] | bgInfoList,: | List of background data from background matching, or None |
[in] | altMaskList,: | List of alternate masks to use rather than those stored with tempExp, or None |
[in] | doClip,: | Use clipping when codding? |
[in] | mask,: | Mask to ignore when coadding |
Definition at line 525 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.assembleMetadata | ( | self, | |
coaddExposure, | |||
tempExpRefList, | |||
weightList | |||
) |
Set the metadata for the coadd.
This basic implementation simply sets the filter from the first input.
[in] | coaddExposure,: | The target image for the coadd |
[in] | tempExpRefList,: | List of data references to tempExp |
[in] | weightList,: | List of weights |
Definition at line 592 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.assembleSubregion | ( | self, | |
coaddExposure, | |||
bbox, | |||
tempExpRefList, | |||
imageScalerList, | |||
weightList, | |||
bgInfoList, | |||
altMaskList, | |||
statsFlags, | |||
statsCtrl | |||
) |
Assemble the coadd for a sub-region.
For each coaddTempExp, check for (and swap in) an alternative mask if one is passed. If background matching is enabled, add the background and background variance from each coaddTempExp. Remove mask planes listed in config.removeMaskPlanes, Finally, mean-stack the actual exposures using statisticsStack with outlier rejection if config.doSigmaClip=True. Assign the stacked subregion back to the coadd.
[in] | coaddExposure,: | The target image for the coadd |
[in] | bbox,: | Sub-region to coadd |
[in] | tempExpRefList,: | List of data reference to tempExp |
[in] | imageScalerList,: | List of image scalers |
[in] | weightList,: | List of weights |
[in] | bgInfoList,: | List of background data from background matching |
[in] | altMaskList,: | List of alternate masks to use rather than those stored with tempExp, or None |
[in] | statsFlags,: | Statistic for coadd |
[in] | statsCtrl,: | Statistics control object for coadd |
Definition at line 637 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.backgroundMatching | ( | self, | |
inputData, | |||
refExpDataRef = None , |
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refImageScaler = None |
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) |
Perform background matching on the prepared inputs.
Each coaddTempExp has a different background level that must be normalized to a reference level before coaddition. If no reference is provided, the background matcher selects one. If the background matching is performed sucessfully, recompute the weight to be applied to the coaddTempExp to be consistent with the scaled background.
[in] | inputData,: | Struct from prepareInputs() with tempExpRefList, weightList, imageScalerList |
[in] | refExpDataRef,: | Data reference for background reference tempExp, or None |
[in] | refImageScaler,: | Image scaler for background reference tempExp, or None |
Definition at line 454 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.getBackgroundReferenceScaler | ( | self, | |
dataRef | |||
) |
Construct an image scaler for the background reference frame.
Each coaddTempExp has a different background level. A reference background level must be chosen before coaddition. If config.autoReference=True, backgroundMatching will pick the reference level and this routine is a no-op and None is returned. Otherwise, use the scaleZeroPoint subtask to compute an imageScaler object for the provided reference image and return it.
[in] | dataRef,: | Data reference for the background reference frame, or None |
Definition at line 363 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.getTempExpRefList | ( | self, | |
patchRef, | |||
calExpRefList | |||
) |
Generate list of coaddTempExp data references corresponding to exposures that lie within the patch to be coadded.
[in] | patchRef,: | Data reference for patch |
[in] | calExpRefList,: | List of data references for input calexps |
Definition at line 347 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.prepareInputs | ( | self, | |
refList | |||
) |
Prepare the input warps for coaddition by measuring the weight for each warp and the scaling for the photometric zero point.
Each coaddTempExp has its own photometric zeropoint and background variance. Before coadding these coaddTempExps together, compute a scale factor to normalize the photometric zeropoint and compute the weight for each coaddTempExp.
[in] | refList,: | List of data references to tempExp |
Definition at line 391 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.readBrightObjectMasks | ( | self, | |
dataRef | |||
) |
Returns None on failure
Definition at line 720 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.run | ( | self, | |
dataRef, | |||
selectDataList = [] |
|||
) |
Assemble a coadd from a set of coaddTempExp.
Coadd a set of coaddTempExps. Compute weights to be applied to each coaddTempExp and find scalings to match the photometric zeropoint to a reference coaddTempExp. Optionally, match backgrounds across coaddTempExps if the background has not already been removed. Assemble the coaddTempExps using assemble. Interpolate over NaNs and optionally write the coadd to disk. Return the coadded exposure.
[in] | dataRef,: | Data reference defining the patch for coaddition and the reference coaddTempExp (if config.autoReference=False). Used to access the following data products:
|
[in] | selectDataList[in],: | List of data references to coaddTempExps. Data to be coadded will be selected from this list based on overlap with the patch defined by dataRef. |
Definition at line 282 of file assembleCoadd.py.
def lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.setBrightObjectMasks | ( | self, | |
exposure, | |||
dataId, | |||
brightObjectMasks | |||
) |
Set the bright object masks exposure: Exposure under consideration dataId: Data identifier dict for patch brightObjectMasks: afwTable of bright objects to mask
Definition at line 728 of file assembleCoadd.py.
lsst.pipe.tasks.assembleCoadd.AssembleCoaddTask.brightObjectBitmask |
Definition at line 275 of file assembleCoadd.py.
|
static |
Definition at line 259 of file assembleCoadd.py.