def _thin_cond_g1():
    '\n    Thinning morphological operation; condition G1\n    :return: a LUT index mask\n    '
    b = np.zeros(512, dtype=int)
    for i in range(1, 5):
        b += (lut_masks_zero(((2 * i) - 1)) & (lut_masks_one((2 * i)) | lut_masks_one(((2 * i) + 1))))
    return (b == 1)
Thinning morphological operation; condition G1
:return: a LUT index mask
def _thin_cond_g1():
    '\n    Thinning morphological operation; condition G1\n    :return: a LUT index mask\n    '
    b = np.zeros(512, dtype=int)
    for i in range(1, 5):
        b += (lut_masks_zero(((2 * i) - 1)) & (lut_masks_one((2 * i)) | lut_masks_one(((2 * i) + 1))))
    return (b == 1)