Convert boolean numpy array to pillow image
Update
This bug has now been solved in Pillow==6.2.0. The link to the issue on GitHub is here.
If you cannot update to the new version of Pillow, please see below.
PIL's Image.fromarray function has a bug with mode '1' images. This Gist demonstrates the bug, and shows a few workarounds. Here are the best two workarounds:
import numpy as npfrom PIL import Image# The standard work-around: first convert to greyscale def img_grey(data): return Image.fromarray(data * 255, mode='L').convert('1')# Use .frombytes instead of .fromarray. # This is >2x faster than img_greydef img_frombytes(data): size = data.shape[::-1] databytes = np.packbits(data, axis=1) return Image.frombytes(mode='1', size=size, data=databytes)
This option might was not available 2018 but currently
from skimage.io._plugins.pil_plugin import ndarray_to_pil, pil_to_ndarrayndarray_to_pil(some_binary_image).convert("1")seems to do the trick.