T.Compose | TypeError: __call__() takes 2 positional arguments but 3 were given

vision
2

There are a few issues in the example code:

  • Even though you are defining your own Compose class, it seems you are still using the torchvision.transforms.Compose one, so you might want to remove the T namespace.
  • Your custom Compose object takes two inputs. However, the underlying torchvision.transforms don’t, so you would have to call the transformation on the image and target separately.
  • Since you are using (one) random transformation, the image and target will not be transformed using the same random number, which might be wrong (e.g. for a segmentation use case). If you want to apply the same random transform on both inputs, have a look at this post
  • RandomHorizontalFlip and Resize work on PIL.Images, so ToTensor should be applied last.

Here is a small dummy example:

class Compose(object):
    def __init__(self, transforms):
        self.transforms = transforms

    def __call__(self, image, target):
        for t in self.transforms:
            image = t(image)
            target = t(target)
        return image, target

import torchvision.transforms as transforms

transform = []
transform.append(transforms.RandomHorizontalFlip(0.5))
transform.append(transforms.Resize(10))
transform.append(transforms.ToTensor())
transform = Compose(transform)

to_image = transforms.ToPILImage()
x = to_image(torch.randn(3, 24, 24))
y = to_image(torch.randn(3, 24, 24))

transform(x, y)
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