A Regularized Conditional GAN for Posterior Sampling in Image Recovery Problems

Matthew C Bendel, Rizwan Ahmad, Philip Schniter

Keywords: Generative adversarial network, inverse problems, posterior sampling, cGAN, GAN

TL;DR: A novel regularization technique that elevates conditional GANs to the state-of-the-art in posterior image sampling.

Abstract:

In image recovery problems, one seeks to infer an image from distorted, incomplete, and/or noise-corrupted measurements.
Such problems arise in magnetic resonance imaging (MRI), computed tomography, deblurring, super-resolution, inpainting, phase retrieval, image-to-image translation, and other applications. Given a training set of signal/measurement pairs, we seek to do more than just produce one good image estimate. Rather, we aim to rapidly and accurately sample from the posterior distribution. To do this,
we propose a regularized conditional Wasserstein GAN that generates dozens of high-quality posterior samples per second. Our regularization comprises an $\ell_1$ penalty and an adaptively weighted standard-deviation reward. Using quantitative evaluation metrics like conditional Fréchet inception distance, we demonstrate that our method produces state-of-the-art posterior samples in both multicoil MRI and large-scale inpainting applications. The code for our model can be found here: https://github.com/matt-bendel/rcGAN.

Submission Number: 14526