StitchedCoadd#

class lsst.cell_coadds.StitchedCoadd(cell_coadd: MultipleCellCoadd, *, bbox: Box2I | None = None)#

Bases: StitchedImagePlanes, CommonComponentsProperties

A lazy-evaluation coadd that stitches together images from adjacent cells.

Parameters#

cell_coaddMultipleCellCoadd: Cell-based coadd to stitch together.
bboxBox2I, optional: The region over which a contiguous coadd is desired. Defaults to cell_coadd.outer_bbox.

Notes#

This class simply inserts subimages from each cell into the full image, doing so when an attribute is first accessed to avoid stitching together planes that may never be accessed.

A StitchedCoadd cannot be serialized in FITS format directly. Instead, the recommended way is to serialize the MultipleCellCoadd instance that was used to construct the object and reconstruct the StitchedCoadd by calling the stitch method on it. A less recommended way is to call the asExposure method to get an lsst.afw.image.Exposure object and persist that to the disk.

Attributes Summary

`ap_corr_map`	Stitch the aperture correction maps from the cell coadd.
`bbox`	The bounding box common to all image planes.
`ccds`	An ExposureCatalog-like object that contains the information about the `ObservationIdentifiers` at any point on the coadd.
`common`	Struct of image components common to all cells in a patch.
`grid`	Object that defines the piecewise grid (of inner cell regions) that this object stitches together.
`mask_fraction_names`	The names of all mask planes whose fractions were propagated in any cell.
`n_noise_realizations`	The number of noise realizations cells are guaranteed to have.
`psf`	The piecewise PSF of this image.
`visits`	An ExposureCatalog-like object that contains the information about the `ObservationIdentifiers` at any point on the coadd.

Methods Summary

`asExposure`(*[, noise_index])	Return an `lsst.afw.image.Exposure` view of this piecewise image.
`set_cell_edges`(*[, edge_width, edge_mask_name])	Set a mask bit indicating the inner cell edges.

Attributes Documentation

ap_corr_map#

Stitch the aperture correction maps from the cell coadd.

This converts the aperture correction maps from each cell into a single ApCorrMap that quacks like lsst.afw.image.ApCorrMap. The resulting object has the fields to correct as keys and a StitchedApertureCorrection for each field.

Notes#

These cannot be attached to an Exposure object.

bbox#

ccds#: An ExposureCatalog-like object that contains the information about the ObservationIdentifiers at any point on the coadd. It can also be used as an iterable to iterate over the unique (visit, detector) combinations.

common#

grid#

Object that defines the piecewise grid (of inner cell regions) that this object stitches together.

This may include cells outside the region covered by these image planes.

mask_fraction_names#

n_noise_realizations#

psf#: The piecewise PSF of this image.

visits#: An ExposureCatalog-like object that contains the information about the ObservationIdentifiers at any point on the coadd. It can also be used as an iterable to iterate over the unique visits.

Methods Documentation

asExposure(*, noise_index: int | None = None) → ExposureF#

Return an lsst.afw.image.Exposure view of this piecewise image.

Parameters#

noise_indexint or None, optional: If specified, return an exposure containing the specified noise realization instead of the data image.

Returns#

exposurelsst.afw.image.ExposureF: The stitched exposure.

Notes#

The returned exposure will have its coaddInputs set. However, its internal representation is very different from those that are genuine afw objects. The records in the ccds and visits tables do not contain the individual bounding boxes and WCSs. Instead, the validPolygon is already in the coadd coordinates. To query the subset of inputs, use the subset_containing_ccds and subset_containing_visits methods on the returned exposure’s getInfo().getCoaddInputs() object.

set_cell_edges(*, edge_width: int = 1, edge_mask_name: str = 'CELL_EDGE') → None#

Set a mask bit indicating the inner cell edges.

Parameters#

edge_widthint, optional: The width of the edge region to flag, in pixels.
edge_mask_namestr, optional: The name of the mask plane to add for the edge region.