Generating Realistic COVID19 X-rays with a Mean Teacher + Transfer Learning GAN

TL;DR

This paper introduces MTT-GAN, a novel GAN model that uses transfer learning and the Mean Teacher algorithm to generate high-quality COVID-19 X-ray images, improving data augmentation for better classification accuracy.

Contribution

The paper presents a new GAN architecture combining transfer learning and Mean Teacher constraints to produce realistic COVID-19 X-rays, enhancing classifier performance.

Findings

MTT-GAN generates high-quality, realistic COVID-19 X-ray images.

Using transfer learning from pneumonia datasets improves GAN stability.

Classifiers trained with MTT-GAN images outperform baseline models.

Abstract

COVID-19 is a novel infectious disease responsible for over 800K deaths worldwide as of August 2020. The need for rapid testing is a high priority and alternative testing strategies including X-ray image classification are a promising area of research. However, at present, public datasets for COVID19 x-ray images have low data volumes, making it challenging to develop accurate image classifiers. Several recent papers have made use of Generative Adversarial Networks (GANs) in order to increase the training data volumes. But realistic synthetic COVID19 X-rays remain challenging to generate. We present a novel Mean Teacher + Transfer GAN (MTT-GAN) that generates COVID19 chest X-ray images of high quality. In order to create a more accurate GAN, we employ transfer learning from the Kaggle Pneumonia X-Ray dataset, a highly relevant data source orders of magnitude larger than public COVID19 datasets. Furthermore, we employ the Mean Teacher algorithm as a constraint to improve stability of training. Our qualitative analysis shows that the MTT-GAN generates X-ray images that are greatly superior to a baseline GAN and visually comparable to real X-rays. Although board-certified radiologists can distinguish MTT-GAN fakes from real COVID19 X-rays. Quantitative analysis shows that MTT-GAN greatly improves the accuracy of both a binary COVID19 classifier as well as a multi-class Pneumonia classifier as compared to a baseline GAN. Our classification accuracy is favourable as compared to recently reported results in the literature for similar binary and multi-class COVID19 screening tasks.