vessel density calculation of fundus image in MATLAB

Hi,

I have segmented blood vessels from the fundus image. I want to calculate vessel density as one my feature from this segmented image (attached here).

I came across the method provided in 'http://www5.informatik.uni-erlangen.de/Forschung/Publikationen/2012/Budai12-BVD-talk.pdf'.

Can any one help me with this? Other possible suggetions are also welcome.

Thanks in advance!

Answer 1

[Image Analyst]

I'd sum the image to get the sum of all white pixels in the mask, then do the same for the convex hull and ratio them

numVesselPixels = sum(mask(:));
chImage = bwconvhull(mask, 'union');
roiArea = sum(chImage(:));
vesselDensity = numVesselPixels / roiArea;

[Bala Amala Kannan]

I tried to calculate vessel density using the approach from paper ''Automated image quality evaluation of retinal fundus photographs in diabetic retinopathy screening ''. I would like to know if this code is same as ur code. What is the use of bwconvhull in your code? Is it to create FOV mask? I have attached my image mask which I have mentioned in my code as 'mask'.

%% Vessel Density feature
    %------ Actual number of pixels(white pixels) in the segmented region
    area_segmented_vessels = regionprops(BW_segmented_img(:), 'Area');
    area_segmented_vessels = [area_segmented_vessels.Area];
    area_segmented_vessels = sum(area_segmented_vessels(:));
    %----- Area of field of view (FOV)
    [~,~,area_FOV] = find(mask==255);
    area_FOV = sum(area_FOV(:));
    %----- Vessel density
    Vessel_density = area_segmented_vessels / area_FOV;

[Image Analyst]

It's only the same if the mask is the same as the convex hull. The convex hull would be roughly circular, like you put a rubber band around your blobs. Your mask will include some areas that definitely will not include vessels. You have to decide what reference area you want. The one you have might be better since it will be the same regardless of patient or how many vessels the patient has.

[Bala Amala Kannan]

Thank you so much. Then I will use the mask I have.