function ostu_img=ostu(B);

%Image contains 2 classes of pixels, foreground and background pixels.

%Calculate optimal threshold such that inter-class variance is maximum

B = imresize(B, [256, 256]);

[r,c] = size(B);

 % Calculation of the normalized histogram

    n = 256;

    h = hist(B(:), n);        

    h = h/(length(B(:))+1);

    % Calculation of the cumulated histogram and the mean values

    cumSum = cumsum(h);

    mu = zeros(n, 1); 

    mu(1) = h(1);

    for i=2:n

        mu(i) = mu(i-1) + i*h(i);

    end    

    % Initialisation of the values used for the threshold calculation

    w0 = cumSum(1);

    w1 = 1-w0;

    mu0 = mu(1)/w0;

    mu1 = (mu(end)-mu(1))/w1;

    max = w0*w1*(mu1-mu0)*(mu1-mu0);

    lev = 1;

    for i = 2:n

        w0 = cumSum(i);

        w1 = 1-w0;

        mu0 = mu(i)/w0;

        mu1 = (mu(end)-mu(i))/w1;

        s = w0*w1*(mu1-mu0)*(mu1-mu0);

        if (s > max)

            max = s;

            lev = i;

        end

    end

    % Normalisation of the threshold        

    lev = lev/n;

    ostu_img = imbinarize(uint8(B),lev);