Visualize Autoencoder Output

Question

I come with a pretty noob question but I'm stuck... I have created a Autoencoder with Pytorch and I trained it with the typical MNIST dataset and so on:

class Autoencoder(nn.Module):
    def __init__(self, **kwargs):
        super().__init__()
        self.encoder_hidden_layer = nn.Linear(
            in_features=kwargs["input_shape"], out_features=kwargs["embedding_dim"]
        )
        self.encoder_output_layer = nn.Linear(
            in_features=kwargs["embedding_dim"], out_features=kwargs["embedding_dim"]
        )
        self.decoder_hidden_layer = nn.Linear(
            in_features=kwargs["embedding_dim"], out_features=kwargs["embedding_dim"]
        )
        self.decoder_output_layer = nn.Linear(
            in_features=kwargs["embedding_dim"], out_features=kwargs["input_shape"]
        )

    def forward(self, features):
        activation = self.encoder_hidden_layer(features)
        activation = torch.relu(activation)

        code = self.encoder_output_layer(activation)
        code = torch.relu(code)
        
        activation = self.decoder_hidden_layer(code)
        activation = torch.relu(activation)

        activation = self.decoder_output_layer(activation)
        reconstructed = torch.relu(activation)

        return reconstructed

model = Autoencoder(input_shape=784, embedding_dim=128)

criterion = nn.MSELoss()
optimizer = optim.Adam(model.parameters(), lr=0.0001)

What I want now is to visualize the reconstructed images, but I don't know how to do it. I know it's quite simple but I cannot find a way. I know that the shape of the output is [128,784] because the batch_size is 128 and 784 is 28x28(x1channel).

Could anyone please tell me how could I get an image from my reconstructed tensor?

Thank you so much!

Ivan · Accepted Answer · 2020-12-06T19:50:27.370

2

First you will have to broadcast the tensor into 128x28x28:

reconstructed = x.reshape(128, 1, 28, 28)

Then, you can convert one of the batch elements into a PIL image using torchvision's functions. The following will show the first image:

import torchvision.transforms as T
img = T.ToPILImage()(reconstructed[0])
img.show()

edited Dec 06 '20 at 19:50

answered Dec 06 '20 at 18:30

Ivan

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Thank you so much! So easy! And another question now: How can I display the image inside the Jupyter Notebook? Because it is opened in an app of my PC instead. And, how can I display everytime the same example? I mean, for every epoch, see how the autoencoder is improving over the same image. Thank you so much!! – Ale Dec 06 '20 at 19:04
1

This https://stackoverflow.com/a/26649884/6331369 will make it so you can preview your image inside Jupyter. You could aopend the first image of the first batch in an array every epoch. At the end you will be able to display each element of that array. – Ivan Dec 06 '20 at 19:17

Visualize Autoencoder Output

1 Answers1