lsst.ip.isr  16.0-4-g6c14c47+7
Classes | Functions | Variables
lsst.ip.isr.crosstalk Namespace Reference

Classes

class  CrosstalkConfig
 
class  CrosstalkTask
 

Functions

def extractAmp (image, amp, corner)
 
def calculateBackground (mi, badPixels=["BAD"])
 
def subtractCrosstalk (exposure, badPixels=["BAD"], minPixelToMask=45000, crosstalkStr="CROSSTALK")
 

Variables

dictionary X_FLIP
 
dictionary Y_FLIP
 

Function Documentation

◆ calculateBackground()

def lsst.ip.isr.crosstalk.calculateBackground (   mi,
  badPixels = ["BAD"] 
)
Calculate median background in image

Getting a great background model isn't important for crosstalk correction,
since the crosstalk is at a low level. The median should be sufficient.

Parameters
----------
mi : `lsst.afw.image.MaskedImage`
    MaskedImage for which to measure background.
badPixels : `list` of `str`
    Mask planes to ignore.

Returns
-------
bg : `float`
    Median background level.

Definition at line 113 of file crosstalk.py.

◆ extractAmp()

def lsst.ip.isr.crosstalk.extractAmp (   image,
  amp,
  corner 
)
Return an image of the amp

The returned image will have the amp's readout corner in the
nominated `corner`.

Parameters
----------
image : `lsst.afw.image.Image` or `lsst.afw.image.MaskedImage`
    Image containing the amplifier of interest.
amp : `lsst.afw.table.AmpInfoRecord`
    Amplifier information.
corner : `lsst.afw.table.ReadoutCorner` or `None`
    Corner in which to put the amp's readout corner, or `None` for
    no flipping.

Returns
-------
output : `lsst.afw.image.Image`
    Image of the amplifier in the standard configuration.

Definition at line 84 of file crosstalk.py.

◆ subtractCrosstalk()

def lsst.ip.isr.crosstalk.subtractCrosstalk (   exposure,
  badPixels = ["BAD"],
  minPixelToMask = 45000,
  crosstalkStr = "CROSSTALK" 
)
Subtract the intra-CCD crosstalk from an exposure

We set the mask plane indicated by ``crosstalkStr`` in a target amplifier
for pixels in a source amplifier that exceed `minPixelToMask`. Note that
the correction is applied to all pixels in the amplifier, but only those
that have a substantial crosstalk are masked with ``crosstalkStr``.

The uncorrected image is used as a template for correction. This is good
enough if the crosstalk is small (e.g., coefficients < ~ 1e-3), but if it's
larger you may want to iterate.

Parameters
----------
exposure : `lsst.afw.image.Exposure`
    Exposure for which to subtract crosstalk.
badPixels : `list` of `str`
    Mask planes to ignore.
minPixelToMask : `float`
    Minimum pixel value in source amplifier for which to set
    ``crosstalkStr`` mask plane in target amplifier.
crosstalkStr : `str`
    Mask plane name for pixels greatly modified by crosstalk.

Definition at line 137 of file crosstalk.py.

Variable Documentation

◆ X_FLIP

dictionary lsst.ip.isr.crosstalk.X_FLIP
Initial value:
1 = {lsst.afw.table.LL: False, lsst.afw.table.LR: True,
2  lsst.afw.table.UL: False, lsst.afw.table.UR: True}

Definition at line 78 of file crosstalk.py.

◆ Y_FLIP

dictionary lsst.ip.isr.crosstalk.Y_FLIP
Initial value:
1 = {lsst.afw.table.LL: False, lsst.afw.table.LR: False,
2  lsst.afw.table.UL: True, lsst.afw.table.UR: True}

Definition at line 80 of file crosstalk.py.