将彩色图像转换为灰度图像

Question

我正在使用宠物数据集。我想将这些图像转换为灰度，但我不知道如何通过互联网浏览，也没有找到很多有用的东西。如果有人能指出我正确的方向，那么我就可以弄清楚如何将其更改为单通道图像或灰度，那会很棒。

from fastai.vision.all import *
set_seed(333)
image_files = get_image_files(path).sorted().shuffle()
splitter = RandomSplitter(valid_pct=0.2, seed=42)
dblock = DataBlock(blocks    = (ImageBlock, CategoryBlock),
                   get_y     = get_y,
                   splitter  = splitter,
                   item_tfms = Resize(224))
dataloaders = dblock.dataloaders(image_files, batch_size=9, shuffle_fn=lambda idxs: idxs)
batch = dataloaders.train.one_batch()
images, labels = batch
show_image_batch((images, labels))

Answer 1

您可以在 DataBlock 中指定图像的类型：ImageBlock(cls=PILImageBW

from fastai.vision.all import *
set_seed(333)
path = untar_data(URLs.PETS)/"images"
image_files = get_image_files(path)
splitter = RandomSplitter(valid_pct=0.2, seed=42)
dblock = DataBlock(blocks    = (ImageBlock(cls=PILImageBW), CategoryBlock),
                   get_y     = lambda x: re.match(r'^(.*)_\d+.jpg$', x.name).groups()[0],
                   splitter  = splitter,
                   item_tfms = [Resize(224)],
                  )

dataloaders = dblock.dataloaders(image_files, batch_size=9)
dataloaders.show_batch()

或者，您可以将您喜欢的任何 transform 应用到您的数据加载器 after_batch。