%% 读取图片
img = imread('船.bmp');
%% 全局阈值二值化
bw = img>65;
figure;
imshow(bw);
%% 横向投影
ys = sum(bw,2);
figure;
plot(ys);
%% 去掉下面的部分和宽度大于1/2的部分
for i=length(ys):-1:1
    if ys(i) > 0
        ys(i) = 0;
    else
        break;
    end
end
ys(ys>size(img,2)/2) = 0;
bw(ys==0,:)=0;
figure;
imshow(bw);
%% 选取最大连通分量
L = bwlabel(bw);
areas = regionprops(L, 'area');
areas = [areas.Area];
index = find(areas==max(areas));
mask=L==index;
figure;
tmp = img;
tmp(mask==0) = 0;
imshow(tmp);



%% 区域生长
figure;
mins = [109*ones(35,1),(121:155)'];
thres = 6;
g_thres = 75;
while ~isempty(mins)
    l = size(mins,1);
    for i = 1:l
        x = mins(i,1);
        y = mins(i,2);
        v = img(x,y);
        if x==1 || y==1 || x==285 || y==378
            continue
        end
        for j=-1:1
            for k=-1:1
                if (abs(img(x+j,y+k)-v) < thres) && (mask(x+j,y+k)==0) && img(x+j,y+k)>g_thres
                    mins = [mins;x+j,y+k];
                    mask(x+j,y+k) = 1;
                end
            end
        end
    end
    mins(1:l,:) = [];
end
subplot(2,2,1);
imshow(mask);
subplot(2,2,2);
ic = imclose(mask,ones(3,3));
imshow(ic);
subplot(2,2,3);
res = img;
res(ic==0)=0;
imshow(res);