分水岭算法及相应处理

matlab中分水岭函数并不能直接得到想要的分割结果。网络上有下面三种处理方式：

代码1：

filename=‘1.jpg';

f=imread(filename);

f=rgb2gray(f);

b1=im2bw(f,0.6);

out=edge(f,'canny',0.3);  

se=strel('disk',1);

b=imclose(b1,se);

b=imopen(b,se);

[X,Y]=size(b);

d=bwdist(b);

I=watershed(-d);

w=I==0;

wait=imfill(w,'holes');

g=f;

g2=imimposemin(d,w);

I2=watershed(g2);

g(w)=0;

wait=imopen(wait,se);

imshow(w);

代码2：

filename='1.jpg';

f=imread(filename);

f=rgb2gray(f);

b=im2bw(f,graythresh(f));

[X,Y]=size(b);

h=fspecial('sobel');

fd=double(f);

g=sqrt(imfilter(fd,h,'replicate').^2+imfilter(fd,h','replicate').^2);

I=watershed(g);

wr=I==0;

g2=imclose(imopen(g,ones(3,3)),ones(3,3));

I2=watershed(g2);

wr2=I2==0;

f2=f;

f2(wr2)=0;

imshow(f);

代码3：

filename='1.jpg';

f=imread(filename);

f=rgb2gray(f);

b=im2bw(f,graythresh(f));

[X,Y]=size(b);

h=fspecial('sobel');

fd=double(f);

g=sqrt(imfilter(fd,h,'replicate').^2+imfilter(fd,h','replicate').^2);

I=watershed(g);

wr=I==0;

rm=imregionalmin(g);

im=imextendedmin(f,50);

lim=watershed(bwdist(im));

em=lim==0;

g2=imimposemin(g,im|em);

I2=watershed(g2);

f2=f;

f2(I2==0)=0;

imshow(f2);

上述的第三种方法为最优方法，不过还是会由于背景的不均匀造成大量的误分割。在做该部分内容时，基于图像重建来去除噪声并进行保留细节特征。代码如下：

clc;

clear;

img=imread('1.jpg');

I=rgb2gray(img);

se = strel('disk', 5);

Ie=imerode(I,se);

Io=imopen(I,se);

subplot(1,2,1);imshow(I,[]);title('gray');

subplot(1,2,2);imshow(Ie);title('腐蚀');

figure;imshow(Io);title('开运算');

Iobr=imreconstruct(Ie,I);

figure;

imshow(Iobr,[]);title('基于开的重建图像');

Iobrd = imdilate(Iobr, se);

Iobrcbr = imreconstruct(imcomplement(Iobrd), imcomplement(Iobr));

Iobrcbr = imcomplement(Iobrcbr);

figure;

imshow(Iobrcbr,[]);title('基于开闭操作的重建图像');

f=Iobrcbr;

%f=rgb2gray(f);

b=im2bw(f,graythresh(f));

%bb=im2bw(ff,graythresh(f));

[X,Y]=size(b);

h=fspecial('sobel');

fd=double(f);

g=sqrt(imfilter(fd,h,'replicate').^2+imfilter(fd,h','replicate').^2);

I=watershed(g);

wr=I==0;

rm=imregionalmin(g);

im=imextendedmin(f,13);

lim=watershed(bwdist(im));

em=lim==0;

g2=imimposemin(g,im|em);

I2=watershed(g2);

f2=f;

f2(I2==1)=255;

figure;

subplot(1,2,1);imshow(b);

subplot(1,2,2);imshow(f2);

figure;

imshow(I2);