Data Augmentation of 3D Brain Environment Using Deep Convolutional Refined Auto-Encoding Alpha GAN

Learning-based methods represent the state of the art in path planning problems. Their performance, however, depend on the number of medical images available for the training. Generative Adversarial Networks (GANs) are unsupervised neural networks that can be exploited to synthesize realistic images avoiding the dependency from the original data. In this article, we propose an innovative type of GAN, Deep Convolutional Refined Auto-Encoding Alpha GAN, able to successfully generate 3D brain Magnetic Resonance Imaging (MRI) data from random vectors by learning the data distribution. We combined a Variational Auto-Encoder GAN with a Code Discriminator to solve the common mode collapse problem and reduce the image blurriness. Finally, we inserted a Refiner in series with the Generator Network in order to smooth the shapes of the images and generate more realistic samples. A qualitative comparison between the generated images and the real ones has been used to test our model's quality. With the use of three indexes, namely the Multi-Scale Structural Similarity Metric, the Maximum Mean Discrepancy and the Intersection over Union, we also performed a quantitative analysis. The final results suggest that our model can be a suitable solution to overcome the shortage of medical images needed for learning-based methods.