astrowisp.hat_masks module

Utilities for working with HAT-style masks in FITS headers.

astrowisp.hat_masks.parse_hat_mask(header)[source]

Extract the HAT-style mask contained in header.

Parameters:: header – The header of the image whose mask to parse.
Returns:: array with exactly the same resolution as the input image containing a bit-field for each pixel indicating any bad-pixel flags raised per the header.
Return type:: numpy.array(dtype=uint8)

Examples

>>> from astropy.io import fits
>>>
>>> with fits.open('/Users/kpenev/tmp/1-447491_4.fits.fz',
>>>                mode='readonly') as f:
>>>     image_mask = parse_hat_mask(f[1].header)
>>>
>>>     flag_name = 'OVERSATURATED'
>>>
>>>     matched = numpy.bitwise_and(image_mask,
>>>                                 mask_flags[flag_name]).astype(bool)
>>>
>>>     #Print number of pixels for which the OVERSATURATED flag is
>>>     #raised
>>>     print(flag_name + ': ' + repr(matched.sum()))
>>>
>>>     #Output x, y, flux for the pixels flagged as OVERSATURATED
>>>     for y, x in zip(*numpy.nonzero(matched)):
>>>         print('%4d %4d %15d' % (x, y, f[1].data[y, x]))