im = imread('prova2.jpg');
im1D = rgb2gray(im);
f = figure;     set(f,'name','Original image');         imshow(im1D,[]);

imBin = im1D > (graythresh(im1D)*255);
imBinNeg = 1 - imBin;
f = figure;     set(f,'name','Binarized negated image');         imshow(imBinNeg,[]);

imBN = imBinNeg;
imSize = size(imBN);

%while (no acabemos xd)
    % Step 1
    flaggedPixels = ones(imSize(1),imSize(2));
    for i = 1:imSize(1)
       for j = 1:imSize(2)
          if imBN(i,j) == 1
              neighbors = [imBN(i-1,j) imBN(i-1,j+1) imBN(i,j+1) imBN(i+1,j+1) imBN(i+1,j) imBN(i+1,j-1) imBN(i,j-1) imBN(i-1,j-1)];
              if min(neighbors) == 0                    % The pixel contains at least a 0 valued neighbor
                  N = sum(neighbors);
                  if N >= 2 && N <= 6                   % Condition a)
                      Ts = CountTransitions(neighbors);
                      if Ts == 1                        % Condition b)
                          if neighbors(4-(1)) == 0 || neighbors(6-(1)) == 0 || neighbors(2-(1))*neighbors(8-(1)) == 0   % Conditions c) & d)
                              flaggedPixels(i,j) = 0;   % Mark the pixel to be removed later
                          end
                      end
                  end
              end
          end
       end
    end
    if min(flaggedPixels) == 0
        imBN = imBN .* flaggedPixels;
    end

    % Step 2
    flaggedPixels = ones(imSize(1),imSize(2));
    for i = 1:imSize(1)
       for j = 1:imSize(2)
          if imBN(i,j) == 1
              neighbors = [imBN(i-1,j) imBN(i-1,j+1) imBN(i,j+1) imBN(i+1,j+1) imBN(i+1,j) imBN(i+1,j-1) imBN(i,j-1) imBN(i-1,j-1)];
              if min(neighbors) == 0                    % The pixel contains at least a 0 valued neighbor
                  N = sum(neighbors);
                  if N >= 2 && N <= 6                   % Condition a)
                      Ts = CountTransitions(neighbors);
                      if Ts == 1                        % Conditions a) & b) are the same ones as before
                          if neighbors(8-(1)) == 0 || neighbors(2-(1)) || neighbors(4-(1))*nighbors(6-(1)) == 0  % Conditions c) & d)
                              flaggedPixels(i,j) = 0;
                          end
                      end
                  end
              end
          end
       end
    end
    if min(flaggedPixels) == 0
        imBN = imBN .* flaggedPixels;
    end

%endwhile