Fig. 1. Flowchart of the proposed method

Fig. 2. Images of the pre-processing results. (a) Color fundus image; (b) green channel; (c) morphological open operation of Fig. 2(b); (d) image enhancement of Fig. 2(c) by CLAHE

Fig. 3. Multi-scale match filter response images. (a) Response image with σ=1; (b) response image with σ=2; (c) response image with all scales

Fig. 4. Schematic diagram of B-COSFIRE. (a) Principle of B-COSFIRE; (b) symmetrical B-COSFIRE structure; (c) asymmetric B-COSFIRE structure

Fig. 5. Response image of B-COSFIRE filtering. (a) Color fundus image; (b) result of B-COSFIRE filtering

Fig. 6. Schematic diagram of line detector structure. (a) Line detector schematic diagram; (b) schematic diagram of line detector matched with vessel; (c) local neighborhood information

Fig. 7. Segmentation result images of the DRIVE database. (a) The best result of images; (b) the worst result of images; (c) segmentation result of 15th images; (d) segmentation result of 18th images

Fig. 8. Segmentation results of lesion image. (a) Segmentation result of K-means; (b) segmentation result of FCM; (c) segmentation result of proposed method

Fig. 9. Results of proposed method and FCM. (a) Results of FCM; (b) results of the proposed method; (c) segmentation images manually marked by expert