def __init__(self, root_dir=r'../data/val_test', image_folder='img/', mask_folder='masks/',
             batch_size=1, image_size=768, nb_y_features=1,
             augmentation=None,
             suffle=True):
    self.image_filenames = listdir_fullpath(os.path.join(root_dir, image_folder))
    self.mask_names = listdir_fullpath(os.path.join(root_dir, mask_folder))
    self.batch_size = batch_size
    self.augmentation = augmentation
    self.image_size = image_size
    self.nb_y_features = nb_y_features
    self.suffle = suffle

def listdir_fullpath(d):
    return np.sort([os.path.join(d, f) for f in os.listdir(d)])