DetectAndMeasureTask

DetectAndMeasureTask performs source detection and execution of measurement plugins in difference images.

Description

This task cross-convolves the difference image with a PSF approximation to obtain maximum-likelihood source candidates. Measurements are run on all the detections, including positive and negative flux candidates. Close sources will be combined, enabling trailed sources as well as dipole-like source detection.

The plugins used by this task by default are meant to provide basic measurements for all types of transient sources: point sources, trailed sources and dipoles as well. Additional forced measurements are provided through PSF flux photometry measurements and centroid determination plugins. Finally, the plugins make use of the image mask planes to provide a wide range of source flags, including streak flagging and injected source flagging.

Python API summary

from lsst.ip.diffim.detectAndMeasure import DetectAndMeasureTask
classDetectAndMeasureTask(**kwargs)

Detect and measure sources on a difference image...

attributeconfig

Access configuration fields and retargetable subtasks.

methodrun(science, matchedTemplate, difference, idFactory=None)

Detect and measure sources on a difference image...

See also

See the DetectAndMeasureTask API reference for complete details.

Retargetable subtasks

applyApCorr

Default

lsst.meas.base.applyApCorr.ApplyApCorrTask

Field type

ConfigurableField

Task to apply aperture corrections

deblend

Default

lsst.meas.deblender.sourceDeblendTask.SourceDeblendTask

Field type

ConfigurableField

Task to split blended sources into their components.

detection

Default

lsst.meas.algorithms.detection.SourceDetectionTask

Field type

ConfigurableField

Final source detection for diaSource measurement

forcedMeasurement

Default

lsst.meas.base.forcedMeasurement.ForcedMeasurementTask

Field type

ConfigurableField

Task to force photometer science image at diaSource locations.

maskStreaks

Default

lsst.meas.algorithms.maskStreaks.MaskStreaksTask

Field type

ConfigurableField

Subtask for masking streaks. Only used if doMaskStreaks is True. Adds a mask plane to an exposure, with the mask plane name set by streakMaskName.

measurement

Default

lsst.ip.diffim.dipoleFitTask.DipoleFitTask

Field type

ConfigurableField

Task to measure sources on the difference image.

setPrimaryFlags

Default

lsst.meas.algorithms.setPrimaryFlags.SetPrimaryFlagsTask

Field type

ConfigurableField

Task to add isPrimary and deblending-related flags to the catalog.

skySources

Default

lsst.meas.algorithms.skyObjects.SkyObjectsTask

Field type

ConfigurableField

Generate sky sources

Configuration fields

badSourceFlags

Default
('base_PixelFlags_flag_offimage', 'base_PixelFlags_flag_interpolatedCenterAll', 'base_PixelFlags_flag_badCenterAll', 'base_PixelFlags_flag_edgeCenterAll', 'base_PixelFlags_flag_saturatedCenterAll')
Field type

str ListField

Sources with any of these flags set are removed before writing the output catalog.

clearMaskPlanes

Default
('DETECTED', 'DETECTED_NEGATIVE', 'NOT_DEBLENDED', 'STREAK')
Field type

str ListField

Mask planes to clear before running detection.

connections

Data type

lsst.pipe.base.config.DetectAndMeasureConfigConnections

Field type

ConfigField

Configurations describing the connections of the PipelineTask to datatypes

diaSourceMatchRadius

Default
0.5
Field type

float Field

Match radius (in arcseconds) for DiaSource to Source association

doAddMetrics

Default
False
Field type

bool Field

Add columns to the source table to hold analysis metrics?

doApCorr

Default
True
Field type

bool Field

Run subtask to apply aperture corrections

doForcedMeasurement

Default
True
Field type

bool Field

Force photometer diaSource locations on PVI?

doMaskStreaks

Default
True
Field type

bool Field

Turn on streak masking

doMerge

Default
True
Field type

bool Field

Merge positive and negative diaSources with grow radius set by growFootprint

doSkySources

Default
False
Field type

bool Field

Generate sky sources?

growFootprint

Default
2
Field type

int Field

Grow positive and negative footprints by this many pixels before merging

idGenerator

Data type

lsst.meas.base._id_generator.DetectorVisitIdGeneratorConfig

Field type

ConfigField

Configuration for how to generate catalog IDs from data IDs.

saveLogOutput

Default
True
Field type

bool Field

Flag to enable/disable saving of log output for a task, enabled by default.

streakBinFactor

Default
4
Field type

int Field

Bin scale factor to use when rerunning detection for masking streaks. Only used if doMaskStreaks is True.

writeStreakInfo

Default
False
Field type

bool Field

Record the parameters of any detected streaks. For LSST, this should be turned off except for development work.