DeferredChargeTask¶
- class lsst.ip.isr.DeferredChargeTask(config: Config | None = None, *, name: str | None = None, parentTask: Task | None = None, log: logging.Logger | lsst.utils.logging.LsstLogAdapter | None = None)¶
Bases:
Task
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).
Methods Summary
Empty (clear) the metadata for this Task and all sub-Tasks.
flipData
(ampData, amp)Flip data array such that readout corner is at lower-left.
Get metadata for all tasks.
Get the task name as a hierarchical name including parent task names.
getName
()Get the name of the task.
Get a dictionary of all tasks as a shallow copy.
local_offset_inverse
(inputArr, drift_scale, ...)Remove CTI effects from local offsets.
local_trap_inverse
(inputArr, trap[, ...])Apply localized trapping inverse operator to pixel signals.
makeField
(doc)Make a
lsst.pex.config.ConfigurableField
for this task.makeSubtask
(name, **keyArgs)Create a subtask as a new instance as the
name
attribute of this task.run
(exposure, ctiCalib[, gains])Correct deferred charge/CTI issues.
timer
(name[, logLevel])Context manager to log performance data for an arbitrary block of code.
Methods Documentation
- static flipData(ampData, amp)¶
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.
- ampData
- Returns:
- ampData
numpy.ndarray
, (nx, ny) Flipped image data.
- ampData
- getFullMetadata() TaskMetadata ¶
Get metadata for all tasks.
- Returns:
- metadata
TaskMetadata
The keys are the full task name. Values are metadata for the top-level task and all subtasks, sub-subtasks, etc.
- metadata
Notes
The returned metadata includes timing information (if
@timer.timeMethod
is used) and any metadata set by the task. The name of each item consists of the full task name with.
replaced by:
, followed by.
and the name of the item, e.g.:topLevelTaskName:subtaskName:subsubtaskName.itemName
using
:
in the full task name disambiguates the rare situation that a task has a subtask and a metadata item with the same name.
- getFullName() str ¶
Get the task name as a hierarchical name including parent task names.
- Returns:
- fullName
str
The full name consists of the name of the parent task and each subtask separated by periods. For example:
The full name of top-level task “top” is simply “top”.
The full name of subtask “sub” of top-level task “top” is “top.sub”.
The full name of subtask “sub2” of subtask “sub” of top-level task “top” is “top.sub.sub2”.
- fullName
- getName() str ¶
Get the name of the task.
- Returns:
- taskName
str
Name of the task.
- taskName
See also
getFullName
Get the full name of the task.
- getTaskDict() dict[str, weakref.ReferenceType[lsst.pipe.base.task.Task]] ¶
Get a dictionary of all tasks as a shallow copy.
- Returns:
- taskDict
dict
Dictionary containing full task name: task object for the top-level task and all subtasks, sub-subtasks, etc.
- taskDict
- static local_offset_inverse(inputArr, drift_scale, decay_time, num_previous_pixels=15)¶
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:
{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.
- inputArr
- Returns:
- outputArr
numpy.ndarray
, (nx, ny) Corrected image data.
- outputArr
- static local_trap_inverse(inputArr, trap, global_cti=0.0, num_previous_pixels=6)¶
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:
{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.
- inputArr
- Returns:
- outputArr
numpy.ndarray
, (nx, ny) Corrected image data.
- outputArr
- classmethod makeField(doc: str) ConfigurableField ¶
Make a
lsst.pex.config.ConfigurableField
for this task.- Parameters:
- doc
str
Help text for the field.
- doc
- Returns:
- configurableField
lsst.pex.config.ConfigurableField
A
ConfigurableField
for this task.
- configurableField
Examples
Provides a convenient way to specify this task is a subtask of another task.
Here is an example of use:
class OtherTaskConfig(lsst.pex.config.Config): aSubtask = ATaskClass.makeField("brief description of task")
- makeSubtask(name: str, **keyArgs: Any) None ¶
Create a subtask as a new instance as the
name
attribute of this task.- Parameters:
- name
str
Brief name of the subtask.
- **keyArgs
Extra keyword arguments used to construct the task. The following arguments are automatically provided and cannot be overridden:
config
.parentTask
.
- name
Notes
The subtask must be defined by
Task.config.name
, an instance ofConfigurableField
orRegistryField
.
- run(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.
- exposure
- Returns:
- exposure
lsst.afw.image.Exposure
The corrected exposure.
- exposure