import numpy as np from PIL import Image import os source_directory = '/home/ubuntu/thesis/data/WSSS4LUAD/2.validation/mask/' output_directory = '/home/ubuntu/thesis/data/WSSS4LUAD/2.validation/masks_relabeled/' dir_list = os.listdir(source_directory) for d in dir_list: arr = np.array(Image.open(source_directory + d)) arr[arr == 3] = 255 arr = arr + 1 Image.fromarray(arr).save(output_directory + d)