ZogyMapper

class lsst.ip.diffim.ZogyMapper(*args, **kwargs)

Bases: lsst.ip.diffim.ZogyTask, lsst.ip.diffim.ImageMapper

Task to be used as an ImageMapper for performing ZOGY image subtraction on a grid of subimages.

Methods Summary

run(subExposure, expandedSubExposure, …) Perform ZOGY proper image subtraction on sub-images

Methods Documentation

run(subExposure, expandedSubExposure, fullBBox, template, **kwargs)

Perform ZOGY proper image subtraction on sub-images

This method performs ZOGY proper image subtraction on subExposure using local measures for image variances and PSF. subExposure is a sub-exposure of the science image. It also requires the corresponding sub-exposures of the template (template). The operations are actually performed on expandedSubExposure to allow for invalid edge pixels arising from convolutions, which are then removed.

Parameters:
subExposure : lsst.afw.image.Exposure

the sub-exposure of the diffim

expandedSubExposure : lsst.afw.image.Exposure

the expanded sub-exposure upon which to operate

fullBBox : lsst.afw.geom.BoundingBox

the bounding box of the original exposure

template : lsst.afw.image.Exposure

the template exposure, from which a corresponding sub-exposure is extracted

kwargs :

additional keyword arguments propagated from ImageMapReduceTask.run. These include:

- doScorr : bool

Compute and return the corrected likelihood image S_corr rather than the proper image difference

- inImageSpace : bool

Perform all convolutions in real (image) space rather than in Fourier space. This option currently leads to artifacts when using real (measured and noisy) PSFs, thus it is set to False by default.

These kwargs may also include arguments to be propagated to ZogyTask.computeDiffim and ZogyTask.computeScorr.
Returns:
A `lsst.pipe.base.Struct` containing the result of the
`subExposure` processing, labelled ‘subExposure’. In this case
it is either the subExposure of the proper image difference D,
or (if `doScorr==True`) the corrected likelihood exposure `S`.

Notes

This run method accepts parameters identical to those of ImageMapper.run, since it is called from the ImageMapperTask. See that class for more information.