🤖 AI Summary
Retinal vessel segmentation and artery/vein (A/V) pixel-wise classification are critical for automated ocular disease screening, yet existing methods suffer from topological inconsistencies and A/V misclassification—especially at vessel crossings and fine branches. To address these challenges, we propose RR-Net, a recursive refinement network featuring a novel multi-stage recursive feature refinement mechanism and an A/V semantic consistency constraint. RR-Net employs a dual-branch decoupled architecture built upon an enhanced U-Net backbone, integrating multi-scale residual gated features. We further design a composite loss function combining Dice, Focal, and KL divergence terms to jointly optimize segmentation and classification. Evaluated on DRIVE, CHASE_DB1, and STARE, RR-Net achieves F1-scores of 98.2%, 97.6%, and 97.9%, respectively—surpassing state-of-the-art methods by over 2.1%—and improves A/V classification accuracy by 4.3%, significantly mitigating crossing misclassifications and branch omissions.