Long-Tailed Multi-Label Retinal Diseases Recognition Using Hierarchical Information and Hybrid Knowledge Distillation

In the real world, medical datasets often exhibit a longtailed data distribution (i.e., a few classes occupy most of the data, while most classes have rarely few samples), which results in a challenging imbalance learning scenario. For example, there are estimated more than 40 different kinds of retinal diseases with variable morbidity, however with more than 30+ conditions are very rare from the global patient cohorts, which results in a typical long-tailed learning problem for deep learning-based screening models. Moreover, there may exist more than one kind of disease on the retina, which results in a multi-label scenario and bring label co-occurrence issue for re-sampling strategy. In this work, we propose a novel framework that leverages the prior knowledge in retinal diseases for training a more robust representation of the model under a hierarchy-sensible constraint. Then, an instance-wise class-balanced sampling strategy and hybrid knowledge distillation manner are firstly introduced to learn from the long-tailed multi-label distribution. Our experiments training on the retinal dataset of more than one million samples demonstrate the superiority of our proposed methods which outperform all competitors and significantly improve the recognition accuracy of most diseases especially those rare diseases.