Learning more expressive joint distributions in multimodal variational methods

TL;DR

This paper enhances multimodal variational models by integrating normalizing flows to better approximate complex joint distributions, leading to improved data representations and sample quality across various vision tasks.

Contribution

It introduces a novel approach that uses normalizing flows to increase the flexibility of the approximate posterior in multimodal variational models.

Findings

Improved performance on computer vision tasks like colorization and edge detection.

Enhanced quality of generated samples.

Outperforms state-of-the-art variational multimodal methods.

Abstract

Data often are formed of multiple modalities, which jointly describe the observed phenomena. Modeling the joint distribution of multimodal data requires larger expressive power to capture high-level concepts and provide better data representations. However, multimodal generative models based on variational inference are limited due to the lack of flexibility of the approximate posterior, which is obtained by searching within a known parametric family of distributions. We introduce a method that improves the representational capacity of multimodal variational methods using normalizing flows. It approximates the joint posterior with a simple parametric distribution and subsequently transforms into a more complex one. Through several experiments, we demonstrate that the model improves on state-of-the-art multimodal methods based on variational inference on various computer vision tasks such as colorization, edge and mask detection, and weakly supervised learning. We also show that learning more powerful approximate joint distributions improves the quality of the generated samples. The code of our model is publicly available at https://github.com/SashoNedelkoski/BPFDMVM.