[Feature Request] Un-Normalize Image Tensor

Basically the inverse of transforms.Normalize as this will allow us to visualize tensors during training more easily.

[fmassa]

I agree with @karandwivedi42 and the comment that he linked to.

If you want to reverse the normalization, all you need to do is to use a new normalization, with slight modifications:

mean = torch.tensor([1, 2, 3], dtype=torch.float32)
std = torch.tensor([2, 2, 2], dtype=torch.float32)

normalize = T.Normalize(mean.tolist(), std.tolist())

unnormalize = T.Normalize((-mean / std).tolist(), (1.0 / std).tolist())

EDIT: fixed thanks to @karandwivedi42 comment

[varunagrawal]

Your solution is pretty much what @fmassa laid out. If you look at his unnormalize method, he is computing the negative mean divided by the standard deviation.