Matlab 实现彩色图像的转换 平滑 锐化与分割

clcf=imread('D:\pic\DIP3E_CH06\Fig0651(a)(flower_no_compression).tif');imshow(f)title('原图像');
[X1,map1]=rgb2ind(f,8,'nodither');figureimshow(X1,map1);%无抖动处理的颜色数减少到8 的图像title('无抖动处理的颜色数减少到8 的图像');
[X2,map2]=rgb2ind(f,8,'dither');figureimshow(X2,map2)%有抖动处理的颜色数减少到8 的图像title('有抖动处理的颜色数减少到8 的图像');
g=rgb2gray(f);g1=dither(g);figure,imshow(g);title('使用函数rgb2gray 得到的原图像的灰度级图像');figure,imshow(g1);title('经抖动处理后的灰度图像（这是一幅二值图像）');

function hsi = rgb2hsi(rgb)
rgb=im2double(rgb);r=rgb(:,:,1);g=rgb(:,:,2);b=rgb(:,:,3);
num=0.5*((r-g)+(r-b));den=sqrt((r-g).^2+(r-b).*(g-b));theta=acos(num./(den+eps));
H=theta;H(b>g)=2*pi-H(b>g);H=H/(2*pi);
num=min(min(r,g),b);den=r+g+b;den(den==0)=eps;S=1-3.*num./den;
H(S==0)=0;I=(r+g+b)/3;
hsi=cat(3,H,S,I);
function rgb=hsi2rgb(hsi)H=hsi(:,:,1)*2*pi;S=hsi(:,:,2);I=hsi(:,:,3);
R=zeros(size(hsi,1),size(hsi,2));G=zeros(size(hsi,1),size(hsi,2));B=zeros(size(hsi,1),size(hsi,2));
idx=find((0<=H)&(H<2*pi/3));B(idx)=I(idx).*(1-S(idx));R(idx)=I(idx).*(1-S(idx).*cos(H(idx))./cos(pi/3-H(idx)));G(idx)=3*I(idx)-(R(idx)+B(idx));
idx=find((2*pi/3<=H)&(H<4*pi/3));R(idx)=I(idx).*(1-S(idx));G(idx)=I(idx).*(1+S(idx).*cos(H(idx)-2*pi/3)./cos(pi-H(idx)));B(idx)=3*I(idx)-(R(idx)+G(idx));
idx=find((4*pi/3<=H)&(H<=2*pi));G(idx)=I(idx).*(1-S(idx));B(idx)=I(idx).*(1+S(idx).*cos(H(idx)-4*pi/3)./cos(5*pi/3-H(idx)));R(idx)=3*I(idx)-(G(idx)+B(idx));
rgb=cat(3,R,G,B);rgb=max(min(rgb,1),0);
%%%%%%%%%%%主函数——图像平滑
clear allclcfc=imread('D:\pic\DIP3E_CH06\Fig0637(a)(caster_stand_original).tif');imshow(fc)h=rgb2hsi(fc);H=h(:,:,1);%显示h 分量图像figure,imshow(H)title('H 分量')S=h(:,:,2);title('S 分量')figure,imshow(S)I=h(:,:,3);figure,imshow(I)title('I 分量')w=fspecial('average',25);I_filtered=imfilter(I,w,'replicate');h=cat(3,H,S,I_filtered);f=hsi2rgb(h);figure,imshow(f)f=min(f,1);%RGB images must have values in the range[0,1]figure,imshow(f)

clear allclcfc=imread('D:\pic\DIP3E_CH06\Fig0637(a)(caster_stand_original).tif');imshow(fc)
lapmask=[1 1 1;1 -8 1;1 1 1];fen=imsubtract(fc,imfilter(fc,lapmask,'replicate'));figure,imshow(fen)

function [C,m]=covmatrix(X)
[K,n]=size(X);X=double(X);if n==1    C=0; m=x;else    m=sum(X,1)/K;    X=X-m(ones(K,1),:);    C=(X'*X)/(K-1);    m=m';end
function I=colorseg(varargin)
f=varargin{2};if(ndims(f)~=3)|(size(f,3)~=3)    error('Input image must be RGB!');endM=size(f,1); N=size(f,2);[f,L]=imstack2vectors(f);f=double(f);I=zeros(M*N,1);T=varargin{3};m=varargin{4};m=m(:)';%make sure that m is a row vetorif length(varargin)==4    method='euclidean';elseif length(varargin)==5    method='mahalanobis';else    error('wrong number of inputs!');endswitch method    case 'euclidean'        p=length(f);        D=sqrt(sum(abs(f-repmat(m,p,1)).^2,2));    case 'mahalanobis'        C=varargin{5};        D=mahalanobis(f,C,m);    otherwise        error('Unknown segmentation method!');end
J=find(D<=T);I(J)=1;I=reshape(I,M,N);
function [X,R]=imstack2vectors(S,MASK)[M,N,n]=size(S);if nargin==1    MASK=true(M,N);else    MASK=MASK~=0;end[I,J]=find(MASK);R=[I,J];Q=M*N;X=reshape(S,Q,n);MASK=reshape(MASK,Q,1);X=X(MASK,:);

%%%%%%RGB 图像分割主程序clear allclcf=imread('D:\pic\DIP3E_CH06\Fig0637(a)(caster_stand_original).tif');mask=roipoly(f);figure,imshow(mask)%mask 是一幅2 值图像（大小与f 相同）red=immultiply(mask,f(:,:,1));figure,imshow(red)title('red 分量');
green=immultiply(mask,f(:,:,2));figure,imshow(green)title('green 分量');
blue=immultiply(mask,f(:,:,3));figure,imshow(blue)title('blue 分量');g=cat(3,red,green,blue);figure,imshow(g)
%计算ROI 中的点的均值向量和协方差矩阵[M,N,K]=size(g);I=reshape(g,M*N,3);idx=find(mask);I=double(I(idx,1:3));[C,m]=covmatrix(I);
d=diag(C);sd=sqrt(d)'E25=colorseg('euclidean',f,25,m);%colorseg('m',f,T,m)T 值可取的值为25 的倍数时得到的不同结果