Understanding and Improving Interpolation in Autoencoders via an Adversarial Regularizer

David Berthelot*, Colin Raffel*, Aurko Roy, Ian Goodfellow

Abstract: Autoencoders provide a powerful framework for learning compressed representations by encoding all of the information needed to reconstruct a data point in a latent code. In some cases, autoencoders can "interpolate": By decoding the convex combination of the latent codes for two datapoints, the autoencoder can produce an output which semantically mixes characteristics from the datapoints. In this paper, we propose a regularization procedure which encourages interpolated outputs to appear more realistic by fooling a critic network which has been trained to recover the mixing coefficient from interpolated data. We then develop a simple benchmark task where we can quantitatively measure the extent to which various autoencoders can interpolate and show that our regularizer dramatically improves interpolation in this setting. We also demonstrate empirically that our regularizer produces latent codes which are more effective on downstream tasks, suggesting a possible link between interpolation abilities and learning useful representations.

TL;DR: We propose a regularizer that improves interpolation and autoencoders and show that it also improves the learned representation for downstream tasks.

Keywords: autoencoders, interpolation, unsupervised learning, representation learning, adversarial learning

Code: [ brain-research/acai](https://github.com/brain-research/acai) + [ 6 community implementations](https://paperswithcode.com/paper/?openreview=S1fQSiCcYm)

Data: [CIFAR-10](https://paperswithcode.com/dataset/cifar-10), [SVHN](https://paperswithcode.com/dataset/svhn)

Community Implementations: [ 6 code implementations](https://www.catalyzex.com/paper/arxiv:1807.07543/code)