aAlgorithmGray.m

function result = aAlgorithmGray(img)
I = rgb2gray(img);

H = imhist(I);
[~,Bval] = max(H);

IB = 155 - Bval;
if Bval>100
  IB = IB + 25;
end
x=IB/255;

BW = imbinarize(I,x);

[counts,~] = imhist(BW);
S=counts(1)/(sum(counts)/100);
while S>10
    if S>20
        x=x-0.01*(S-10)/5; %for speed
    end
    x=x-0.01;
    BW = imbinarize(I,x);
    [counts,~] = imhist(BW);
    S=counts(1)/(sum(counts)/100);
end

BW=bwareaopen(BW, 100);
binaryImg = imcomplement(BW);
binaryImg=bwareaopen(binaryImg, 5000);


result = binaryImg;

end