Exposure Level Processing¶
- Class:
- Alias:
exposure_pipeline
The ExposurePipeline
applies detector-level corrections to given exposure
types (imaging, prism, and grism.). It is applied to one
exposure at a time.
It is sometimes referred to as “ramps-to-slopes” processing, because the input
raw data are in the form of ramps containing accumulating counts from the
non-destructive detector readouts and the output is a corrected countrate
(slope) image.
The list of steps applied by the ExposurePipeline
pipeline is shown in the
table below.
Step |
WFI-Image |
WFI-Prism |
WFI-Grism |
---|---|---|---|
✓ |
✓ |
✓ |
|
✓ |
✓ |
✓ |
|
✓ |
✓ |
✓ |
|
✓ |
✓ |
✓ |
|
✓ |
✓ |
✓ |
|
✓ |
✓ |
✓ |
|
✓ |
✓ |
✓ |
|
✓ |
|||
✓ |
|||
✓ |
|||
✓ |
Arguments¶
The exposure
pipeline has an optional argument:
--use_ramp_jump_detection boolean default=True
When set to True
, the pipeline will perform jump detection as a part of the ramp
fitting step. The data at this stage of the pipeline are still in the form of the original
3D ramps ( ngroups x ncols x nrows ) and have had all of the detector-level
correction steps applied to it, up to but not including the detection and flagging of
Cosmic-Ray (CR) hits within each ramp (integration). For this case the jump
module in ramp_fitting will update the dq array with the CR hits (jumps) that
are identified in the step.
Inputs¶
3D raw data¶
- Data model:
RampModel
- File suffix:
_uncal
The input to the ExposurePipeline
is a single raw exposure,
e.g. “r0008308002010007027_06311_0019_WFI01_uncal.asdf”, which contains the
original raw data from all of the detector readouts in the exposure
( ngroups x ncols x nrows ).
Note that in the operational environment, the
input will be in the form of a RawScienceModel
, which only
contains the 3D array of detector pixel values, along with some optional
extensions. When such a file is loaded into the pipeline, it is immediately
converted into a RampModel
, and has all additional data arrays
for errors and Data Quality flags created and initialized.
Outputs¶
2D Image model¶
- Data model:
ImageModel
- File suffix:
_cal
Result of applying all pipeline steps up through the tweakreg step is to produce calibrated data with the image WCS aligned to Gaia, and is 2D image data, which will have one less data dimensions as the input raw 3D data. In addition to being a 2-dimensional image the output from the pipeline has the reference pixels removed from the edges of the science array and saved as additional 3D arrays.