图像分割原理：

图像分割函数代码：

function [dst,realT1,realT2] = ImageSegmentation(filepath)
%图像分割
src = double(rgb2gray(imread(filepath)));
[M,N] = size(src);
src = reshape(src,[],1);
mG = mean(src);
g = 0;realT1 = min(src);realT2 = realT1+1;
for T1 = min(src) : max(src)-2
    for T2 = T1+1 : max(src)-1
        index = find(src<=T1);
        p1 = length(index)/(M*N);
        m1 = mean(src(index));
        index = find(src>T1 & src<=T2);
        p2 = length(index)/(M*N);
        m2 = mean(src(index));
        index = find(src>T2);
        p3 = length(index)/(M*N);
        m3 = mean(src(index));
        if g < p1*(m1-mG)^2+p2*(m2-mG)^2+p3*(m3-mG)^2
            g = p1*(m1-mG)^2+p2*(m2-mG)^2+p3*(m3-mG)^2;
            realT1 = T1;realT2 = T2;
        end
    end
end
dst = zeros(size(src));
index = find(src>realT1 & src<=realT2);
dst(index) = 0.5;
index = find(src>realT2);
dst(index) = 1;
dst = reshape(dst,M,N);
end

演示代码：

%% 图像分割
filepath = '...';
[dst,T1,T2] = ImageSegmentation(filepath);
imshow(dst);

运行结果：

输入图像：

图像分割结果：