lsst.ip.isr.measureCrosstalk Namespace Reference

Classes
class	MeasureCrosstalkConfig
class	MeasureCrosstalkTask

Functions
def	extractCrosstalkRatios (exposure, threshold=30000, badPixels=["SAT", BAD, INTRP)
def	measureCrosstalkCoefficients (ratios, rejIter=3, rejSigma=2.0)

Function Documentation

extractCrosstalkRatios()

def lsst.ip.isr.measureCrosstalk.extractCrosstalkRatios	(		exposure,
			threshold = 30000,
			badPixels = ["SAT",
			BAD,
			INTRP
	)

Extract crosstalk ratios between different amplifiers

For pixels above ``threshold``, we calculate the ratio between each
target amp and source amp. We return a list of ratios for each pixel
for each target/source combination, as a matrix of lists.

Parameters
----------
exposure : `lsst.afw.image.Exposure`
    Exposure for which to measure crosstalk.
threshold : `float`
    Lower limit on pixels for which we measure crosstalk.
badPixels : `list` of `str`
    Mask planes indicating a pixel is bad.

Returns
-------
ratios : `list` of `list` of `numpy.ndarray`
    A matrix of pixel arrays. ``ratios[i][j]`` is an array of
    the fraction of the ``j``-th amp present on the ``i``-th amp.
    The value is `None` for the diagonal elements.

Definition at line 41 of file measureCrosstalk.py.

measureCrosstalkCoefficients()

def lsst.ip.isr.measureCrosstalk.measureCrosstalkCoefficients	(		ratios,
			rejIter = 3,
			rejSigma = 2.0
	)

Measure crosstalk coefficients from the ratios

Given a list of ratios for each target/source amp combination,
we measure a robust mean and error.

The coefficient errors returned are the (robust) standard deviation of
the input ratios.

Parameters
----------
ratios : `list` of `list` of `numpy.ndarray`
    Matrix of arrays of ratios.
rejIter : `int`
    Number of rejection iterations.
rejSigma : `float`
    Rejection threshold (sigma).

Returns
-------
coeff : `numpy.ndarray`
    Crosstalk coefficients.
coeffErr : `numpy.ndarray`
    Crosstalk coefficient errors.
coeffNum : `numpy.ndarray`
    Number of pixels for each measurement.

Definition at line 87 of file measureCrosstalk.py.