Step Arguments

The outlier detection step has the following optional arguments that control the behavior of the processing. For more details about step arguments (including datatypes, possible values and defaults) see jwst.outlier_detection.OutlierDetectionStep.spec.

General Step Arguments

The following arguments apply to all modes unless otherwise specified:

--save_intermediate_results

Specifies whether or not to save any intermediate products created during step processing.

--good_bits

The DQ bit values from the input image DQ arrays that should be considered ‘good’. Any pixel with a DQ value not included in this value (or list of values) will be ignored when resampling and flagged when building the weight mask. See DQ flag Parameter Specification for details. Has no effect for IFU data.

--snr

The signal-to-noise values to use for bad pixel identification. Since cosmic rays often extend across several pixels, the user must specify two cut-off values for determining whether a pixel should be masked: the first for detecting the primary cosmic ray, and the second (typically lower threshold) for masking lower-level bad pixels adjacent to those found in the first pass. Valid values are a pair of floating-point values in a single string (for example “5.0 4.0”). Has no effect for IFU data.

Step Arguments for Imaging and Slit-like Spectroscopic data

--weight_type

The type of data weighting to apply to the resampled data. Available options are ivm (default) to compute and use an inverse-variance map, and exptime to weight by the exposure time.

--pixfrac

The pixel fraction used during resampling; valid values go from 0.0 to 1.0. Indicates the fraction by which input pixels are “shrunk” before being drizzled onto the output image grid. This specifies the size of the footprint, or “dropsize”, of a pixel in units of the input pixel size.

--kernel

The form of the kernel function used to distribute flux onto a resampled image.

--fillval

The value to assign to resampled image pixels that have zero weight or do not receive any flux from any input pixels during drizzling. Any floating-point value, given as a string, is valid. The default value of ‘NAN’ sets NaN values.

--maskpt

The percent of maximum weight to use as lower-limit for valid data; valid values go from 0.0 to 1.0.

--scale

The scaling factor applied to derivative used to identify bad pixels. Since cosmic rays often extend across several pixels the user must specify two cut-off values for determining whether a pixel should be masked: the first for detecting the primary cosmic ray, and the second (typically lower threshold) for masking lower-level bad pixels adjacent to those found in the first pass. Valid values are a pair of floating-point values in a single string (for example “1.2 0.7”).

--backg

User-specified background value to apply to the median image.

--resample_data

Specifies whether or not to resample the input images when performing outlier detection.

--in_memory

Specifies whether or not to load and create all images that are used during processing into memory. If False, input files are loaded from disk when needed and all intermediate files are stored on disk, rather than in memory. Has no effect for spectroscopic data. For imaging data this parameter is superseded by the pipeline-level in_memory parameter set by calwebb_image3.

Step Arguments for IFU data

--kernel_size

The size of the kernel to use to normalize the pixel differences. The kernel size must only contain odd values. Valid values are a pair of ints in a single string (for example “7 7”, the default).

--threshold_percent

The threshold (in percent) of the normalized minimum pixel difference used to identify bad pixels. Pixels with a normalized minimum difference above this percentage are flagged as outliers.

--ifu_second_check

Perform a secondary check searching for outliers. This will set outliers where ever the difference array of adjacent pixels is a Nan.

Step Arguments for TSO data

--rolling_window_width

Number of integrations over which to take the median when using rolling-window median for TSO observations. The default is 25. If the number of integrations is less than or equal to rolling_window_width, a simple median is used instead.

Step Arguments for Coronagraphic data

General step arguments apply to coronagraphic data. No additional arguments are used.