ComputeExposureSummaryStatsTask¶
- class lsst.pipe.tasks.computeExposureSummaryStats.ComputeExposureSummaryStatsTask(**kwargs)¶
Bases:
Task
Task to compute exposure summary statistics.
This task computes various quantities suitable for DPDD and other downstream processing at the detector centers, including: - psfSigma - psfArea - psfIxx - psfIyy - psfIxy - ra - dec - zenithDistance - zeroPoint - skyBg - skyNoise - meanVar - raCorners - decCorners - astromOffsetMean - astromOffsetStd
These additional quantities are computed from the stars in the detector: - psfStarDeltaE1Median - psfStarDeltaE2Median - psfStarDeltaE1Scatter - psfStarDeltaE2Scatter - psfStarDeltaSizeMedian - psfStarDeltaSizeScatter - psfStarScaledDeltaSizeScatter
These quantities are computed based on the PSF model and image mask to assess the robustness of the PSF model across a given detector (against, e.g., extrapolation instability): - maxDistToNearestPsf - psfTraceRadiusDelta
These quantities are computed to assess depth: - effTime - effTimePsfSigmaScale - effTimeSkyBgScale - effTimeZeroPointScale
Methods Summary
Empty (clear) the metadata for this Task and all sub-Tasks.
Get metadata for all tasks.
Get the task name as a hierarchical name including parent task names.
getName
()Get the name of the task.
Get a dictionary of all tasks as a shallow copy.
makeField
(doc)Make a
lsst.pex.config.ConfigurableField
for this task.makeSubtask
(name, **keyArgs)Create a subtask as a new instance as the
name
attribute of this task.run
(exposure, sources, background)Measure exposure statistics from the exposure, sources, and background.
timer
(name[, logLevel])Context manager to log performance data for an arbitrary block of code.
update_background_stats
(summary, background)Compute summary-statistic fields that depend only on the background model.
update_effective_time_stats
(summary, exposure)Compute effective exposure time statistics to estimate depth.
update_masked_image_stats
(summary, masked_image)Compute summary-statistic fields that depend on the masked image itself.
update_photo_calib_stats
(summary, photo_calib)Compute all summary-statistic fields that depend on the photometric calibration model.
update_psf_stats
(summary, psf, bbox[, ...])Compute all summary-statistic fields that depend on the PSF model.
update_wcs_stats
(summary, wcs, bbox, visitInfo)Compute all summary-statistic fields that depend on the WCS model.
Methods Documentation
- getFullMetadata() TaskMetadata ¶
Get metadata for all tasks.
- Returns:
- metadata
TaskMetadata
The keys are the full task name. Values are metadata for the top-level task and all subtasks, sub-subtasks, etc.
- metadata
Notes
The returned metadata includes timing information (if
@timer.timeMethod
is used) and any metadata set by the task. The name of each item consists of the full task name with.
replaced by:
, followed by.
and the name of the item, e.g.:topLevelTaskName:subtaskName:subsubtaskName.itemName
using
:
in the full task name disambiguates the rare situation that a task has a subtask and a metadata item with the same name.
- getFullName() str ¶
Get the task name as a hierarchical name including parent task names.
- Returns:
- fullName
str
The full name consists of the name of the parent task and each subtask separated by periods. For example:
The full name of top-level task “top” is simply “top”.
The full name of subtask “sub” of top-level task “top” is “top.sub”.
The full name of subtask “sub2” of subtask “sub” of top-level task “top” is “top.sub.sub2”.
- fullName
- getName() str ¶
Get the name of the task.
- Returns:
- taskName
str
Name of the task.
- taskName
See also
getFullName
Get the full name of the task.
- getTaskDict() dict[str, weakref.ReferenceType[lsst.pipe.base.task.Task]] ¶
Get a dictionary of all tasks as a shallow copy.
- Returns:
- taskDict
dict
Dictionary containing full task name: task object for the top-level task and all subtasks, sub-subtasks, etc.
- taskDict
- classmethod makeField(doc: str) ConfigurableField ¶
Make a
lsst.pex.config.ConfigurableField
for this task.- Parameters:
- doc
str
Help text for the field.
- doc
- Returns:
- configurableField
lsst.pex.config.ConfigurableField
A
ConfigurableField
for this task.
- configurableField
Examples
Provides a convenient way to specify this task is a subtask of another task.
Here is an example of use:
class OtherTaskConfig(lsst.pex.config.Config): aSubtask = ATaskClass.makeField("brief description of task")
- makeSubtask(name: str, **keyArgs: Any) None ¶
Create a subtask as a new instance as the
name
attribute of this task.- Parameters:
- name
str
Brief name of the subtask.
- **keyArgs
Extra keyword arguments used to construct the task. The following arguments are automatically provided and cannot be overridden:
config
.parentTask
.
- name
Notes
The subtask must be defined by
Task.config.name
, an instance ofConfigurableField
orRegistryField
.
- run(exposure, sources, background)¶
Measure exposure statistics from the exposure, sources, and background.
- Parameters:
- exposure
lsst.afw.image.ExposureF
- sources
lsst.afw.table.SourceCatalog
- background
lsst.afw.math.BackgroundList
- exposure
- Returns:
- summary
lsst.afw.image.ExposureSummary
- summary
- timer(name: str, logLevel: int = 10) Iterator[None] ¶
Context manager to log performance data for an arbitrary block of code.
- Parameters:
See also
lsst.utils.timer.logInfo
Implementation function.
Examples
Creating a timer context:
with self.timer("someCodeToTime"): pass # code to time
- update_background_stats(summary, background)¶
Compute summary-statistic fields that depend only on the background model.
- Parameters:
- summary
lsst.afw.image.ExposureSummaryStats
Summary object to update in-place.
- background
lsst.afw.math.BackgroundList
orNone
Background model. If
None
, all fields that depend on the background will be reset (generally to NaN).
- summary
Notes
This does not include fields that depend on the background-subtracted masked image; when the background changes, it should generally be applied to the image and
update_masked_image_stats
should be called as well.
- update_effective_time_stats(summary, exposure)¶
Compute effective exposure time statistics to estimate depth.
The effective exposure time is the equivalent shutter open time that would be needed under nominal conditions to give the same signal-to-noise for a point source as what is achieved by the observation of interest. This metric combines measurements of the point-spread function, the sky brightness, and the transparency.
The effective exposure time and its subcomponents are defined in [1]
- Parameters:
- summary
lsst.afw.image.ExposureSummaryStats
Summary object to update in-place.
- exposure
lsst.afw.image.ExposureF
Exposure to grab band and exposure time metadata
- summary
References
[1]Neilsen, E.H., Bernstein, G., Gruendl, R., and Kent, S. (2016). Limiting Magnitude, au, teff, and Image Quality in DES Year 1 https://www.osti.gov/biblio/1250877/
- update_masked_image_stats(summary, masked_image)¶
Compute summary-statistic fields that depend on the masked image itself.
- update_photo_calib_stats(summary, photo_calib)¶
Compute all summary-statistic fields that depend on the photometric calibration model.
- update_psf_stats(summary, psf, bbox, sources=None, image_mask=None, sources_is_astropy=False)¶
Compute all summary-statistic fields that depend on the PSF model.
- Parameters:
- summary
lsst.afw.image.ExposureSummaryStats
Summary object to update in-place.
- psf
lsst.afw.detection.Psf
orNone
Point spread function model. If
None
, all fields that depend on the PSF will be reset (generally to NaN).- bbox
lsst.geom.Box2I
Bounding box of the image for which summary stats are being computed.
- sources
lsst.afw.table.SourceCatalog
orastropy.table.Table
Catalog for quantities that are computed from source table columns. If
None
, these quantities will be reset (generally to NaN). The type of this table must correspond to thesources_is_astropy
argument.- image_mask
lsst.afw.image.Mask
, optional Mask image that may be used to compute distance-to-nearest-star metrics.
- sources_is_astropy
bool
, optional Whether
sources
is anastropy.table.Table
instance instead of anlsst.afw.table.Catalog
instance. Default isFalse
(the latter).
- summary
- update_wcs_stats(summary, wcs, bbox, visitInfo)¶
Compute all summary-statistic fields that depend on the WCS model.
- Parameters:
- summary
lsst.afw.image.ExposureSummaryStats
Summary object to update in-place.
- wcs
lsst.afw.geom.SkyWcs
orNone
Astrometric calibration model. If
None
, all fields that depend on the WCS will be reset (generally to NaN).- bbox
lsst.geom.Box2I
Bounding box of the image for which summary stats are being computed.
- visitInfo
lsst.afw.image.VisitInfo
Observation information used in together with
wcs
to compute the zenith distance.
- summary