Diagonal Hierarchical Consistency Learning for Semi-supervised Medical Image Segmentation
Heejoon Koo
TL;DR
The paper tackles the high annotation cost in medical image segmentation by introducing DiHC-Net, a semi-supervised framework built from three identical multi-scale V-Net sub-models with distinct sub-layers. It combines deep supervision on labeled data with two consistency mechanisms: mutual consistency via sharpened pseudo labels and a novel diagonal hierarchical consistency that links pseudo labels to other models' intermediate and final predictions, optimized through a warming-up loss schedule. Empirical results on LA and BraTS 2019 demonstrate that DiHC-Net outperforms several strong baselines, with ablations confirming the contribution of multi-scale diversification and the DiHC loss to performance gains. This approach offers a robust, relatively simple strategy to leverage unlabeled data in MIS, tightening segmentation accuracy and contour fidelity while reducing annotation demands.
Abstract
Medical image segmentation, which is essential for many clinical applications, has achieved almost human-level performance via data-driven deep learning technologies. Nevertheless, its performance is predicated upon the costly process of manually annotating a vast amount of medical images. To this end, we propose a novel framework for robust semi-supervised medical image segmentation using diagonal hierarchical consistency learning (DiHC-Net). First, it is composed of multiple sub-models with identical multi-scale architecture but with distinct sub-layers, such as up-sampling and normalisation layers. Second, with mutual consistency, a novel consistency regularisation is enforced between one model's intermediate and final prediction and soft pseudo labels from other models in a diagonal hierarchical fashion. A series of experiments verifies the efficacy of our simple framework, outperforming all previous approaches on public benchmark dataset covering organ and tumour.
