calwebb_image2: Stage 2 Imaging Processing

Class

jwst.pipeline.Image2Pipeline

Alias

calwebb_image2

Stage 2 imaging processing applies additional instrumental corrections and calibrations that result in a fully calibrated individual exposure. There are two parameter references used to control this pipeline, depending on whether the data are to be treated as Time Series Observation (TSO). The parameter reference is provided by CRDS and the reftype pars-image2pipeline. In general, for non-TSO exposures, all applicable steps are applied to the data. For TSO exposures, some steps are set to be skipped by default (see the list of steps in the table below).

The list of steps applied by the Image2Pipeline pipeline is shown in the table below.

Step

Non-TSO

TSO

background

assign_wcs

flat_field

photom

resample 1

1

Resampling is only performed for exposure types “MIR_IMAGE”, “NRC_IMAGE”, and “NIS_IMAGE”.

Arguments

The calwebb_image2 pipeline has one optional argument:

--save_bsub  boolean  default=False

If set to True, the results of the background subtraction step will be saved to an intermediate file, using a product type of “_bsub” or “_bsubints”, depending on whether the data are 2D (averaged over integrations) or 3D (per-integration results).

Inputs

2D or 3D countrate data

Data model

ImageModel or CubeModel

File suffix

_rate or _rateints

The input to Image2Pipeline is a countrate exposure, in the form of either “_rate” or “_rateints” data. A single input file can be processed or an ASN file listing multiple inputs can be used, in which case the processing steps will be applied to each input exposure, one at a time. If “_rateints” products are used as input, each step applies its algorithm to each integration in the exposure, where appropriate.

TSO and coronagraphic exposures are expected to use 3D data as input, to be processed on a per-integration basis.

Outputs

2D or 3D background-subtracted data

Data model

ImageModel or CubeModel

File suffix

_bsub or _bsubints

This is an intermediate product that is only created if “–save_bsub” is set to True and will contain the data as output from the background step. If the input is a “_rate” product, this will be a “_bsub” product, while “_rateints” inputs will be saved as “_bsubints.”

2D or 3D calibrated data

Data model

ImageModel or CubeModel

File suffix

_cal or _calints

The output is a fully calibrated, but unrectified, exposure, using the product type suffix “_cal” or “_calints”, depending on the type of input, e.g. “jw80600012001_02101_00003_mirimage_cal.fits”.

2D resampled image

Data model

ImageModel

File suffix

_i2d

This is the output of the resample step and is only created for regular direct imaging observations (not for TSO or coronagraphy 3D data sets). The output file will use the “_i2d” product type suffix, e.g. “jw80600012001_02101_00003_mirimage_i2d.fits”. Note that this product is intended for quick-look use only and is not passed along as input to Stage 3 processing. Calibrated, but unrectified (_cal) products are used as input to Stage 3.