PreProcess.m

function imf=PreProcess(im)

% h = fspecial('gaussian',7,0.5);
% imfilt = imfilter(im, h, 'symmetric');
% for j=1:50
%     imfilt = imfilter(imfilt, h, 'symmetric');
% end

imfilt = imgaussfilt(im);
imhfreq = max((im - imfilt), zeros(size(im)));
imf = medfilt2(imhfreq,[3 3]);
imf=stdfilt(imf,getnhood(strel('disk',5)));
imf = mat2gray(imf);