Extraction of Blood Vessels in Retinal Images Using Four Different Techniques

Figure 10

Matched filter results when kernel with 𝑤=6 is applied to the image in Figure 1(a) for four different orientations, (a) image obtained when matched filter kernel was at an angle 𝜃=0^∘, (b) image obtained when matched filter kernel was at an angle 𝜃=45^∘, (c) image obtained when matched filter kernel was at an angle 𝜃=90^∘, (d) image obtained when matched filter kernel was at an angle 𝜃=135^∘.