A comparison of latent space modeling techniques in a plain-vanilla autoencoder setting

By sampling from the latent space of an autoencoder and decoding the latent space samples to the original data space, any autoencoder can be turned into a generative model. For this to work, it is necessary to model the latent space with a distribution from which samples can be obtained. Several simple possibilities such as kernel density estimates or a Gaussian distribution and more sophisticated ones such as Gaussian mixture models, copula models, and normalization flows can be thought of and have been tried recently. In a plain-vanilla autoencoder setting, this study aims to discuss, assess, and compare various techniques that can be used to capture the latent space so that an autoencoder can become a generative model. Furthermore, we provide insights into further aspects of these methods, such as targeted sampling or synthesizing new data with specific features.