Cross-Scale Fuzzy Holistic Attention Network for Diabetic Retinopathy Grading From Fundus Images

Diabetic Retinopathy (DR) is one of the leading causes of visual impairment and blindness in diabetic patients worldwide. Accurate Computer-Aided Diagnosis (CAD) systems can aid in the early diagnosis and treatment of DR patients to reduce the risk of vision loss, but it remains challenging due to the following reasons: 1) the relatively low contrast and ambiguous boundaries between pathological lesions and normal retinal regions, and 2) the considerable diversity in lesion size and appearance. In this paper, a Cross-Scale Fuzzy Holistic Attention Network (CSFHANet) is proposed for DR grading using fundus images, and it consists of two main components: Fuzzy-Enhanced Holistic Attention (FEHA) and Fuzzy Learning-based Cross-Scale Fusion (FLCSF). FEHA is developed to adaptively recalibrate the importance of feature elements by assigning fuzzy weights across both channel and spatial domains, which can enhance the model's ability to learn the features of lesion regions while reducing the interference from irrelevant information in normal retinal regions. Then, the FLCSF module is designed to eliminate the uncertainty in fused multi-scale features derived from different branches by utilizing fuzzy membership functions, producing a more comprehensive and refined feature representation from complex DR lesions. Extensive experiments on the Messidor-2 and DDR datasets demonstrate that the proposed CSFHANet exhibits superior performance compared to state-of-the-art methods.