lsst.ip.isr g8db5811388+31d8c72c14
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Public Member Functions | Static Public Member Functions | Static Public Attributes | List of all members
lsst.ip.isr.deferredCharge.DeferredChargeTask Class Reference
Inheritance diagram for lsst.ip.isr.deferredCharge.DeferredChargeTask:

Public Member Functions

def run (self, exposure, ctiCalib, gains=None)
 

Static Public Member Functions

def flipData (ampData, amp)
 
def local_offset_inverse (inputArr, drift_scale, decay_time, num_previous_pixels=15)
 
def local_trap_inverse (inputArr, trap, global_cti=0.0, num_previous_pixels=6)
 

Static Public Attributes

 ConfigClass = DeferredChargeConfig
 

Detailed Description

Task to correct an exposure for charge transfer inefficiency.

This uses the methods described by Snyder et al. 2021, Journal of
Astronimcal Telescopes, Instruments, and Systems, 7,
048002. doi:10.1117/1.JATIS.7.4.048002 (Snyder+21).

Definition at line 526 of file deferredCharge.py.

Member Function Documentation

◆ flipData()

def lsst.ip.isr.deferredCharge.DeferredChargeTask.flipData (   ampData,
  amp 
)
static
Flip data array such that readout corner is at lower-left.

Parameters
----------
ampData : `numpy.ndarray`, (nx, ny)
    Image data to flip.
amp : `lsst.afw.cameraGeom.Amplifier`
    Amplifier to get readout corner information.

Returns
-------
ampData : `numpy.ndarray`, (nx, ny)
    Flipped image data.

Definition at line 603 of file deferredCharge.py.

◆ local_offset_inverse()

def lsst.ip.isr.deferredCharge.DeferredChargeTask.local_offset_inverse (   inputArr,
  drift_scale,
  decay_time,
  num_previous_pixels = 15 
)
static
Remove CTI effects from local offsets.

    This implements equation 10 of Snyder+21.  For an image with
    CTI, s'(m, n), the correction factor is equal to the maximum
    value of the set of:

    .. code-block::

        {A_L s'(m, n - j) exp(-j t / \tau_L)}_j=0^jmax

    Parameters
    ----------
    inputArr : `numpy.ndarray`, (nx, ny)
        Input image data to correct.
    drift_scale : `float`
        Drift scale (Snyder+21 A_L value) to use in correction.
    decay_time : `float`
        Decay time (Snyder+21 \tau_L) of the correction.
    num_previous_pixels : `int`, optional
        Number of previous pixels to use for correction.  As the
        CTI has an exponential decay, this essentially truncates
        the correction where that decay scales the input charge to
        near zero.

    Returns
    -------
    outputArr : `numpy.ndarray`, (nx, ny)
        Corrected image data.

Definition at line 635 of file deferredCharge.py.

◆ local_trap_inverse()

def lsst.ip.isr.deferredCharge.DeferredChargeTask.local_trap_inverse (   inputArr,
  trap,
  global_cti = 0.0,
  num_previous_pixels = 6 
)
static
Apply localized trapping inverse operator to pixel signals.

    This implements equation 13 of Snyder+21.  For an image with
    CTI, s'(m, n), the correction factor is equal to the maximum
    value of the set of:

    .. code-block::

        {A_L s'(m, n - j) exp(-j t / \tau_L)}_j=0^jmax

    Parameters
    ----------
    inputArr : `numpy.ndarray`, (nx, ny)
        Input image data to correct.
    trap : `lsst.ip.isr.SerialTrap`
        Serial trap describing the capture and release of charge.
    global_cti: `float`
        Mean charge transfer inefficiency, b from Snyder+21.
    num_previous_pixels : `int`, optional
        Number of previous pixels to use for correction.

    Returns
    -------
    outputArr : `numpy.ndarray`, (nx, ny)
        Corrected image data.

Definition at line 682 of file deferredCharge.py.

◆ run()

def lsst.ip.isr.deferredCharge.DeferredChargeTask.run (   self,
  exposure,
  ctiCalib,
  gains = None 
)
Correct deferred charge/CTI issues.

Parameters
----------
exposure : `lsst.afw.image.Exposure`
    Exposure to correct the deferred charge on.
ctiCalib : `lsst.ip.isr.DeferredChargeCalib`
    Calibration object containing the charge transfer
    inefficiency model.
gains : `dict` [`str`, `float`]
    A dictionary, keyed by amplifier name, of the gains to
    use.  If gains is None, the nominal gains in the amplifier
    object are used.

Returns
-------
exposure : `lsst.afw.image.Exposure`
    The corrected exposure.

Definition at line 536 of file deferredCharge.py.

Member Data Documentation

◆ ConfigClass

lsst.ip.isr.deferredCharge.DeferredChargeTask.ConfigClass = DeferredChargeConfig
static

Definition at line 533 of file deferredCharge.py.


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