lsst.pipe.tasks gb62d540790+dc6f37d311
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Public Member Functions | Public Attributes | List of all members
lsst.pipe.tasks.background.FocalPlaneBackground Class Reference

Public Member Functions

def fromCamera (cls, config, camera)
 
def fromSimilar (cls, other)
 
def __init__ (self, config, dims, transform, values=None, numbers=None)
 
def __reduce__ (self)
 
def clone (self)
 
def addCcd (self, exposure)
 
def toCcdBackground (self, detector, bbox)
 
def merge (self, other)
 
def __iadd__ (self, other)
 
def getStatsImage (self)
 

Public Attributes

 config
 
 dims
 
 transform
 

Detailed Description

Background model for a focal plane camera

We model the background empirically with the "superpixel" method: we
measure the background in each superpixel and interpolate between
superpixels to yield the model.

The principal difference between this and `lsst.afw.math.BackgroundMI`
is that here the superpixels are defined in the frame of the focal
plane of the camera which removes discontinuities across detectors.

The constructor you probably want to use is the `fromCamera` classmethod.

There are two use patterns for building a background model:

* Serial: create a `FocalPlaneBackground`, then `addCcd` for each of the
  CCDs in an exposure.

* Parallel: create a `FocalPlaneBackground`, then `clone` it for each
  of the CCDs in an exposure and use those to `addCcd` their respective
  CCD image. Finally, `merge` all the clones into the original.

Once you've built the background model, you can apply it to individual
CCDs with the `toCcdBackground` method.

Definition at line 498 of file background.py.

Constructor & Destructor Documentation

◆ __init__()

def lsst.pipe.tasks.background.FocalPlaneBackground.__init__ (   self,
  config,
  dims,
  transform,
  values = None,
  numbers = None 
)
Constructor

Developers should note that changes to the signature of this method
require coordinated changes to the `__reduce__` and `clone` methods.

Parameters
----------
config : `FocalPlaneBackgroundConfig`
    Configuration for measuring backgrounds.
dims : `lsst.geom.Extent2I`
    Dimensions for background samples.
transform : `lsst.afw.geom.TransformPoint2ToPoint2`
    Transformation from focal plane coordinates to sample coordinates.
values : `lsst.afw.image.ImageF`
    Measured background values.
numbers : `lsst.afw.image.ImageF`
    Number of pixels in each background measurement.

Definition at line 569 of file background.py.

Member Function Documentation

◆ __iadd__()

def lsst.pipe.tasks.background.FocalPlaneBackground.__iadd__ (   self,
  other 
)
Merge with another FocalPlaneBackground

Parameters
----------
other : `FocalPlaneBackground`
    Another background model to merge.

Returns
-------
self : `FocalPlaneBackground`
    The merged background model.

Definition at line 741 of file background.py.

◆ __reduce__()

def lsst.pipe.tasks.background.FocalPlaneBackground.__reduce__ (   self)

Definition at line 607 of file background.py.

◆ addCcd()

def lsst.pipe.tasks.background.FocalPlaneBackground.addCcd (   self,
  exposure 
)
Add CCD to model

We measure the background on the CCD (clipped mean), and record
the results in the model.  For simplicity, measurements are made
in a box on the CCD corresponding to the warped coordinates of the
superpixel rather than accounting for little rotations, etc.
We also record the number of pixels used in the measurement so we
can have a measure of confidence in each bin's value.

Parameters
----------
exposure : `lsst.afw.image.Exposure`
    CCD exposure to measure

Definition at line 613 of file background.py.

◆ clone()

def lsst.pipe.tasks.background.FocalPlaneBackground.clone (   self)

Definition at line 610 of file background.py.

◆ fromCamera()

def lsst.pipe.tasks.background.FocalPlaneBackground.fromCamera (   cls,
  config,
  camera 
)
Construct from a camera object

Parameters
----------
config : `FocalPlaneBackgroundConfig`
    Configuration for measuring backgrounds.
camera : `lsst.afw.cameraGeom.Camera`
    Camera for which to measure backgrounds.

Definition at line 524 of file background.py.

◆ fromSimilar()

def lsst.pipe.tasks.background.FocalPlaneBackground.fromSimilar (   cls,
  other 
)
Construct from an object that has the same interface.

Parameters
----------
other : `FocalPlaneBackground`-like
    An object that matches the interface of `FocalPlaneBackground`
    but which may be different.

Returns
-------
background : `FocalPlaneBackground`
    Something guaranteed to be a `FocalPlaneBackground`.

Definition at line 553 of file background.py.

◆ getStatsImage()

def lsst.pipe.tasks.background.FocalPlaneBackground.getStatsImage (   self)
Return the background model data

This is the measurement of the background for each of the superpixels.

Definition at line 756 of file background.py.

◆ merge()

def lsst.pipe.tasks.background.FocalPlaneBackground.merge (   self,
  other 
)
Merge with another FocalPlaneBackground

This allows multiple background models to be constructed from
different CCDs, and then merged to form a single consistent
background model for the entire focal plane.

Parameters
----------
other : `FocalPlaneBackground`
    Another background model to merge.

Returns
-------
self : `FocalPlaneBackground`
    The merged background model.

Definition at line 715 of file background.py.

◆ toCcdBackground()

def lsst.pipe.tasks.background.FocalPlaneBackground.toCcdBackground (   self,
  detector,
  bbox 
)
Produce a background model for a CCD

The superpixel background model is warped back to the
CCD frame, for application to the individual CCD.

Parameters
----------
detector : `lsst.afw.cameraGeom.Detector`
    CCD for which to produce background model.
bbox : `lsst.geom.Box2I`
    Bounding box of CCD exposure.

Returns
-------
bg : `lsst.afw.math.BackgroundList`
    Background model for CCD.

Definition at line 665 of file background.py.

Member Data Documentation

◆ config

lsst.pipe.tasks.background.FocalPlaneBackground.config

Definition at line 588 of file background.py.

◆ dims

lsst.pipe.tasks.background.FocalPlaneBackground.dims

Definition at line 589 of file background.py.

◆ transform

lsst.pipe.tasks.background.FocalPlaneBackground.transform

Definition at line 590 of file background.py.


The documentation for this class was generated from the following file: