Deep Reinforcement Active Learning for Medical Image Classification

In this paper, we propose a deep reinforcement learning algorithm for active learning on medical image data. Although deep learning has achieved great success on medical image processing, it relies on a large number of labeled data for training, which is expensive and time-consuming. Active learning, which follows a strategy to select and annotate informative samples, is an effective approach to alleviate this issue. However, most existing methods of active learning adopt a hand-design strategy, which cannot handle the dynamic procedure of classifier training. To address this issue, we model the procedure of active learning as a Markov decision process, and propose a deep reinforcement learning algorithm to learn a dynamic policy for active learning. To achieve this, we employ the actor-critic approach, and apply the deep deterministic policy gradient algorithm to train the model. We conduct experiments on two kinds of medical image data sets, and the results demonstrate that our method is able to learn better strategy compared with the existing hand-design ones.