SAFRON: Stitching Across the Frontier for Generating Colorectal Cancer Histology Images

Synthetic images can be used for the development and evaluation of deep learning algorithms in the context of limited availability of data. In the field of computational pathology, where histology images are large in size and visual context is crucial, synthesis of large high resolution images via generative modeling is a challenging task. This is due to memory and computational constraints hindering the generation of large images. To address this challenge, we propose a novel SAFRON (Stitching Across the FRONtiers) framework to construct realistic, large high resolution tissue image tiles from ground truth annotations while preserving morphological features and with minimal boundary artifacts. We show that the proposed method can generate realistic image tiles of arbitrarily large size after training it on relatively small image patches. We demonstrate that our model can generate high quality images, both visually and in terms of the Frechet Inception Distance. Compared to other existing approaches, our framework is efficient in terms of the memory requirements for training and also in terms of the number of computations to construct a large high-resolution image. We also show that training on synthetic data generated by SAFRON can significantly boost the performance of a state-of-the-art algorithm for gland segmentation in colorectal cancer histology images. Sample high resolution images generated using SAFRON are available at the URL: https://warwick.ac.uk/TIALab/SAFRON