DM-4692 and DM-5348 overhaul ProcessCcdTask
and introduce some backwards-incompatible changes.
Code changes
-
ProcessCoaddTask
is gone, along with all bin scripts that run it. Use the new Multi-Band code, instead. -
ProcessCcdTask
has been rewritten, so its config has changed. Config override files will need to be updated. This will be done for the obs_ packages as part of the merge, but if you have personal config override files then you will probably need to update them. -
Camera-specific variants of
ProcessCcdTask
are gone. You will runbin/processCcdTask.py
to process images for all cameras. -
For DECam
bin/processCcdTask.py
will use the LSST stack’s ISR by default. To readinstcal
files from the community pipeline, replace the ISR task withDecamNullIsrTask
by using a config override file containing the following:from lsst.obs.decam.decamNullIsr import DecamNullIsrTask
config.isr.retarget(DecamNullIsrTask) -
A new dynamic dataset type is available for adding data ID arguments to the argument parser for command-line tasks:
ConfigDatasetType
obtains the dataset type from a config parameter. -
Various subtasks have changed, including:
- New camera-specific ISR task variants for SDSS and DECam:
SdssNullIsrTask
andDecamNullIsrTask
. - New task
DetectAndMeasureTask
detects and deblends sources and performs single-frame measurement. - New task
CharacterizeImageTask
measures PSF and aperture correction, among other things. -
CalibrateTask
has been rewritten. It now performs deep detection and measurement, astrometry and photometry. - Camera-specific variants of
CalibrateTask
are gone. -
ProcessImageTask
(formerly a base class forProcessCcdTask
andProcessCoaddTask
) is gone.
- New camera-specific ISR task variants for SDSS and DECam:
Data product changes
-
icSrc
no longer includes RA/Dec coordinate data, because the fit WCS is not available when the catalog is constructed. You will have to set the coord field yourself if you need it. -
icExp
andicExpBackground
can optionally be written byCharacterizeImageTask
. They are so close tocalexp
andcalexpBackground
that they are not written by default. -
icMatch
is no longer being written.
Algorithm changes
- PSF is fit somewhat differently. The new task fits the PSF in using a configurable number of iterations. By default each iteration starts with a simple Gaussian PSF whose sigma matches the PSF of the previous fit, but you can use the actual PSF each time. Using a Gaussian causes convergence in 2 iterations. Using the fit PSF slows convergence.
- Sources in the
icSrc
catalog should have a more consistent minimum SNR for varying seeing. The old code detected once, using a Gaussian PSF with FWHM set by a config parameter. The new code performs detection using the PSF in the final PSF iteration. - The default star selector for
MeasurePsfTask
isobjectSize
rather thansizeMagnitude
. TheobjectSize
star selector is preferred and was already being specified as an override by HSC. - The icSrc catalog is not matched to an astrometric reference catalog unless the star selector used to measure PSF can use the matches (which is unusual).
- The astrometric and photometric solution now use the deeper
src
catalog instead of the shallowericSrc
catalog, though with a new SNR cutoff whose default provides a depth similar to theicSrc
catalog. - Fake source handling is temporarily missing; it will be re-added in DM-5310.