Comparative Study of Retinal Vessel Segmentation Based on Global Thresholding Techniques

Algorithm 3

Algorithm for phase congruence global-based thresholding technique.

(1) Input the colored retinal image

(2) Extract the green channel of the colored retinal image

(3) Perform preprocessing on image using phase congruence as indicated in (5)

(4) Further enhance the preprocessed image using average filter

(5) Segment image using any of the following thresholding techniques:

   (i) Otsu threshold using (9)

   (ii) ISODATA threshold using (10)

   (iii) IDM-based threshold computed in Algorithm 2

(6) Perform morphological operation for noise removal

(7) Subtract image mask to obtain segmented vascular network