[D] Making an autoencoder rotation invariant for image clustering?

I'm trying to cluster PDF files that I've converted into images, and I've gotten a good suggestion to train an autoencoder with convolutional layers and cluster in the latent space. I'm hoping to implement this with Keras.

The problem I'm running into is that these PDF files are scans, so some of the files are slightly rotated, and some of them are rotated by a full 90 degrees. As far as I know autoencoders are generally not rotation invariant, and …

autoencoder cluster clustering files good image images keras machinelearning making pdf rotation running scans space train