prysm.bayer

Basic operations for bayer data.

prysm.bayer.wb_prescale(mosaic, wr, wg1, wg2, wb, cfa='rggb')

Apply white-balance prescaling in-place to mosaic.

Parameters

• mosaic (numpy.ndarray) – ndarray of shape (m, n), a float dtype

• wr (float) – red white balance prescalar

• wg1 (float) – G1 white balance prescalar

• wg2 (float) – G2 white balance prescalar

• wb (float) – blue white balance prescalar

• cfa (str, optional, {'rggb', 'bggr'}) – color filter arrangement

prysm.bayer.wb_scale(trichromatic, wr, wg, wb)

Apply white balance scaling in-place to trichromatic.

Parameters

• trichromatic (numpy.ndarray) – ndarray of shape (m, n, 3), a float dtype

• wr (float) – red scale factor, out = in * wr

• wg (float) – green scale factor, out = in * wg

• wb (float) – blue scale factor, out = in * wb

prysm.bayer.composite_bayer(r, g1, g2, b, cfa='rggb', output=None)

Composite an interleaved image from densely sampled bayer color planes.

Parameters

• r (numpy.ndarray) – ndarray of shape (m, n)

• g1 (numpy.ndarray) – ndarray of shape (m, n)

• g2 (numpy.ndarray) – ndarray of shape (m, n)

• b (numpy.ndarray) – ndarray of shape (m, n)

• cfa (str, optional, {'rggb', 'bggr'}) – color filter arangement

• output (numpy.ndarray, optional) – output array, of shape (m, n) and same dtype as r, g1, g2, b

Returns

array of interleaved data

Return type

numpy.ndarray

prysm.bayer.decomposite_bayer(img, cfa='rggb')

Decomposite an interleaved image into densely sampled color planes.

Parameters

• img (numpy.ndarray) – composited ndarray of shape (m, n)

• cfa (str, optional, {'rggb', 'bggr'}) – color filter arangement

Returns

• r (numpy.ndarray) – ndarray of shape (m//2, n//2)

• g1 (numpy.ndarray) – ndarray of shape (m//2, n//2)

• g2 (numpy.ndarray) – ndarray of shape (m//2, n//2)

• b (numpy.ndarray) – ndarray of shape (m//2, n//2)

prysm.bayer.recomposite_bayer(r, g1, g2, b, cfa='rggb', output=None)

Recomposite raw color planes back into a mosaic.

This function is the reciprocal of decomposite_bayer

Parameters

• r (numpy.ndarray) – ndarray of shape (m, n)

• g1 (numpy.ndarray) – ndarray of shape (m, n)

• g2 (numpy.ndarray) – ndarray of shape (m, n)

• b (numpy.ndarray) – ndarray of shape (m, n)

• cfa (str, optional, {'rggb', 'bggr'}) – color filter arangement

• output (numpy.ndarray, optional) – output array, of shape (2m, 2n) and same dtype as r, g1, g2, b

Returns

array containing the re-composited color planes

Return type

numpy.ndarray

prysm.bayer.demosaic_malvar(img, cfa='rggb')

Demosaic an image using the Malvar algorithm.

Parameters

• img (numpy.ndarray) – ndarray of shape (m, n) containing mosaiced (interleaved) pixel data, as from a raw file

• cfa (str, optional, {'rggb', 'bggr'}) – color filter arrangement

Returns

ndarray of shape (m, n, 3) that has been demosaiced. Final dimension is ordered R, G, B. Is of the same dtype as img and has the same energy content and sense of z scaling

Return type

numpy.ndarray