Highpass filter type Butterworth

Read 'cameraman.tif' and convert it to a double, then filter it with a highpass Butterworth filter (in a frequency domain) , cutoff frequency 40 px and level 5. Binarize (level 0.1, highpass). Find all the pixels 20 px above the closest 'true' pixel. Count the number of isolated territories and their areas. Is ot correct?

if true
  img = imread('cameraman.tif');
img = double(img)/255;
fft = fftshift(fft2(img));

N = 5; D0 = 40; D = zeros(256); H = zeros(256);

 for kz=1:256
   for kx=1:256
           %Butterworth
           D(kz,kx) = sqrt( (kz-128)^2 + (kx-128)^2);
           H(kz,kx) = 1/(1+(D(kz,kx)/D0)^2*N);
  end
end

filtered = fft.*(1-H);

result = ifft2(ifftshift(filtered)); figure; subplot(121); imshow(img); title('Oryginalny'); subplot(122); imshow(result); title('Przefiltrowany');

binarized = im2bw(real(result), 0.1);

ilosc= bwdist(binarized)>20 ; ilosc=sum(ilosc(:)) figure; imshow(binarized); title('Zbinaryzowany');

w = binarized == 1; b = binarized == 0; biale = sum(w(:)); czarne = sum(b(:));

[blab, blobs] = bwlabel(binarized); end