get_nirspec_persistence_mask

grizli.jwst_utils.get_nirspec_persistence_mask(file='jw01180136001_11101_00002_nrs1_rate.fits', ok_bits=4, rnoise_threshold=10, closing_iterations=2, erosion_iterations=4, dilation_iterations=1, verbose=True, **kwargs)[source]

Make a mask for NIRSpec pixels likely to cause persistence.

Parameters
filestr

Filename of a NIRSPec exposure file with a minimum of 'DQ' and 'VAR_RNOISE' extensions.

ok_bitsint

DQ bits to ignore when making the mask

rnoise_thresholdfloat

Threshold for masking pixels relative to median(VAR_RNOISE)

closing_iterationsint

Number of binary_closing iterations on initial mask initial = valid_dq & VAR_RNOISE > rnoise_threshold * median_rnoise

erosion_iterationsint

Number of binary_erosion iterations

dilation_iterationsint

Number of isotropic_dilation iterations

Returns
flaggedbool array

Final mask defined by

initial = valid_dq & (VAR_RNOISE > rnoise_threshold * median_rnoise)
closed = scipy.ndimage.binary_closing(initial, closing_iterations)
eroded = scipy.ndimage.binary_erosion(closed, erosion_iterations)
flagged = skimage.morphology.isotropic_dilation(eroded, dilation_iterations)