A gated task-attentive multi-task network for unified retinal image analysis

Diabetic retinopathy (DR) is one of the major causes of preventable blindness in the world, and accurate large-scale screening tools are needed urgently. Most of the deep learning methods which have been developed for retinal image analysis are treating tasks like optic disc segmentation and DR grading separately. This separation is making it difficult for the model to use the shared anatomical and contextual cues which are linking the two tasks. So we are proposing GTAM-Net, a Gated Task-Attentive Multi-Task Network for retinal image analysis. GTAM-Net is performing optic disc segmentation and DR severity grading together inside a single end-to-end network. Inside the network, a gated task-attentive block is deciding how the features should be shared between the two tasks at each layer. In this way the network is keeping the useful complementary information for each task, and at the same time it is avoiding the negative transfer which often hurts multi-task models. We are also using a multi-scale feature pyramid for keeping the hierarchical context, and an uncertainty-based loss weighting so that one task is not dominating the training. The proposed method is tested on five public datasets: IDRiD, DDR, Messidor-2, APTOS, and REFUGE. The model is reaching up to 98.17% Dice score for optic disc segmentation and 99.12% accuracy for DR grading, and the performance of the proposed method is competitive on every dataset that we tried. The cross-dataset tests are also showing that the model is fairly stable when the imaging conditions are changing. From these results, the proposed multi-task design is appearing to be a useful and reasonably stable option for joint retinal image analysis, and it can be considered for use in large screening pipelines.