hi, am doing my project in Diabetic Retinopathy, for that I need to calculate the background image. I didnt get output . pls check my code and help me to get the output

a=imread('RGB image filename');
%imtool(a)to crop center portion of an eye image
b=imcrop(a,[178.5 27.5 349 542]);
c=rgb2gray(b);

%basic background image separation ie., gray to binary
%s=min intensity value of c:max intensity value of c
for s=63:224
    threshforc=118;
    if c(s)<threshforc
        c(s)=0;
    else
        c(s)=1;    
    end
    imshow(c(s));  
end

I tried im2bw also. I need to do with threshold value only but i got the output as 1 or 0 in the command window insted of binary image.wat can i do

Answer 1

[David Sanchez]

BW = im2bw(I, level) converts the grayscale image I to a binary image.

Answer 2

[Image Analyst]

Not correct. You're using linear indexing to binarize just the first column of your grayscale image, c. Most likely not what you want. I doubt global thresholding would be good for fundus images anyway (for a couple of years my dissertation work was on fundus images before I switched to radiology). You can post your image if you'd like more advice. You can also check here for algorithms of people who got it right and published their method: http://iris.usc.edu/Vision-Notes/bibliography/contentsmedical.html#Medical%20Applications,%20CAT,%20MRI,%20Ultrasound,%20Heart%20Models,%20Brain%20Models