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Sample what you can't compress; image auto-encoders wihtout GANs (arxiv.org)
19 points by vighneshb on Oct 17, 2024 | hide | past | pdf | 4 comments on HN

In plain words: An autoencoder is trained with a denoising loss, and its random decoder invents details the compressed code cannot hold. It rebuilds images more faithfully than the usual approach that sharpens them by training against a fake-image detector, and is easier to tune.

Abstract · Sample what you cant compress

For learned image representations, basic autoencoders often produce blurry results. Reconstruction quality can be improved by incorporating additional penalties such as adversarial (GAN) and perceptual losses. Arguably, these approaches lack a principled interpretation. Concurrently, in generative settings diffusion has demonstrated a remarkable ability to create crisp, high quality results and has solid theoretical underpinnings (from variational inference to direct study as the Fisher Divergence). Our work combines autoencoder representation learning with diffusion and is, to our knowledge, the first to demonstrate jointly learning a continuous encoder and decoder under a diffusion-based loss and showing that it can lead to higher compression and better generation. We demonstrate that this approach yields better reconstruction quality as compared to GAN-based autoencoders while being easier to tune. We also show that the resulting representation is easier to model with a latent diffusion model as compared to the representation obtained from a state-of-the-art GAN-based loss. Since our decoder is stochastic, it can generate details not encoded in the otherwise deterministic latent representation; we therefore name our approach "Sample what you can't compress", or SWYCC for short.

Vighnesh Birodkar, Gabriel Barcik, James Lyon, Sergey Ioffe, David Minnen, Joshua V. Dillon
arXiv:2409.02529 · cs.LG, cs.CV · submitted Sep 4, 2024 · updated Sep 24, 2025
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Hi

In our latest paper we shoa that a GAN loss (used by almost all latent diffusion models) to train their autoencoders is not required and instead can be replaced with a diffusion loss. Our auto-encoder is trained end-to-end and achieves higher compression and better generation quality.

I am excited to share it with you. Let me know what you think.

Cheers

I just saw https://hanlab.mit.edu/projects/hart

it seems to be another autoencoder(autoregressive) + diffusion.

This is very interesting. Unlike us (who focus on the decoder) they focus on changing the representation itself so that they can achieve better generation. Thanks for the link.
they use autoencoder/autoregressive model to predict the big picture, and diffusion for the details, similar to yours.

The difference is they use discrete tokens.