Understanding and Visualizing Generalization in UNets

Abhejit Rajagopal, Vamshi Chowdary Madala, Thomas A Hope, Peder Larson

Keywords: generalization, deep learning, unets, visual representations

TL;DR: We propose new techniques for visualizing interior features of UNets and new metrics that exploit those features to predict generalization (test) performance on previously-unseen data.

Abstract: Fully-convolutional neural networks, such as the 2D or 3D UNet, are now pervasive in medical imaging for semantic segmentation, classification, image denoising, domain translation, and reconstruction. However, evaluation of UNet performance, as with most CNNs, has mostly been relegated to evaluation of a few performance metrics (e.g. accuracy, IoU, SSIM, etc.) using the network's final predictions, which provides little insight into important issues such as dataset shift that occur in clinical application. In this paper, we propose techniques for understanding and visualizing the generalization performance of UNets in image classification and regression tasks, giving rise to metrics that are indicative of performance on a withheld test-set without the need for groundtruth annotations.

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Paper Type: methodological development

Primary Subject Area: Uncertainty Estimation

Secondary Subject Area: Interpretability and Explainable AI

Source Code Url: https://gitlab.com/abhe/UNet-Generalization_MIDL2021