Solved by tom in post #2 
              
              
                So Normalize does x_norm=(x-mean)/std. If you want to undo that, you could do x = x_norm * std[None, :, None, None] + mean[None, :, None, None] (the indexing aligning the channel dimension) or if you prefer magic, reframe it as (leaving out the indexing) x = (x_norm + (mean / std)) * std and then yo…