数字图像处理:RGB 与 HSI 模型转换 Matlab 程序 im1=imread('Fig6.30(01).jpg'); im3=im1; im1=im2double(im1); [m,n,q]=size(im1); % 获取图像的 RGB 3 个通道 R=im1(:,:,1); G=im1(:,:,2); B=im1(:,:,3); % 改变通道来观察图像 figure,subplot(1,3,1),imshow(cat(3,R*0.5,G,B)),title('R 通道减半'); set(gcf,'outerposition',get(0,'screensize')); set(gcf,'NumberTitle','off','Name','改变通道来观察图像'); subplot(1,3,2),imshow(cat(3,R,G*2,B)),title('G 通道翻倍'); subplot(1,3,3),imshow(cat(3,R,G,zeros(m,n))),title('B 通道为 0'); % 观察 HSI 通道图像 % 因系统没有 rgb2hsi 函数,只有 rgb2hsv 函数,所以自己编写程序实现 H=zeros(m,n); S=H; for i1=1:m for i2=1:n numerator=0.5*(R(i1,i2)-G(i1,i2)+R(i1,i2)-B(i1,i2)); denominator=sqrt((R(i1,i2)-G(i1,i2))^2+(R(i1,i2)-B(i1, i2))*(G(i1,i2)-B(i1,i2))); theta=acos(numerator/denominator)*180/pi; if(B(i1,i2)<=G(i1,i2)) H(i1,i2)=theta; else H(i1,i2)=360-theta; end min1=min(R(i1,i2),G(i1,i2)); min1=min(B(i1,i2),min1); S(i1,i2)=1-3/(R(i1,i2)+G(i1,i2)+B(i1,i2))*min1; end end I=(R+G+B)/3; figure,subplot(1,3,1),imshow(H,[]),title('色度图 H'); set(gcf,'outerposition',get(0,'screensize')); set(gcf,'NumberTitle','off','Name','HSI 通道图像'); 

subplot(1,3,2),imshow(S),title('饱和度图 S'); subplot(1,3,3),imshow(I),title('强度图 I'); % 从 HSI 转换回 RGB 模型并观察图像,系统也不自带 hsi2rgb,仅自带 hsv2rgb im2=zeros(m,n,3); for i1=1:m for i2=1:n value1=I(i1,i2)*(1+S(i1,i2)*cos(H(i1,i2))/cos(pi/3-H(i 1,i2)/180*pi)); value2=I(i1,i2)*(1-S(i1,i2)); switch (floor(H(i1,i2)/120)) case 0 im2(i1,i2,1)=value1; im2(i1,i2,2)=3*I(i1,i2)-R(i1,i2)-B(i1, im2(i1,i2,3)=value2; case 1 H(i1,i2)=H(i1,i2)-120; im2(i1,i2,1)=value2; im2(i1,i2,2)=value1; im2(i1,i2,3)=3*I(i1,i2)-R(i1,i2)-G(i1, case 2 H(i1,i2)=H(i1,i2)-240; im2(i1,i2,1)=3*I(i1,i2)-G(i1,i2)-B(i1, im2(i1,i2,2)=value2; im2(i1,i2,3)=value1; i2); i2); i2); end end end % 模型转换完毕,显示图像 figure,subplot(1,2,1),imshow(im1),title('原图'); set(gcf,'outerposition',get(0,'screensize')); set(gcf,'NumberTitle','off','Name','原图与 HSI 转 RGB 通道图像对比'); subplot(1,2,2),imshow(im2),title('HSI 转 RGB 通道图像'); % 给图像添加噪声 im3=imnoise(im3,'salt & pepper',0.02); R=im3(:,:,1); 

G=im3(:,:,2); B=im3(:,:,3); R=medfilt2(R); G=medfilt2(G); B=medfilt2(B); im4=cat(3,R,G,B); figure,subplot(1,3,1),imshow(im1),title('原图'); set(gcf,'outerposition',get(0,'screensize')); set(gcf,'NumberTitle','off','Name','图像对比'); subplot(1,3,2),imshow(im3),title('加入椒盐噪声后图像'); subplot(1,3,3),imshow(im4),title('中值滤波后图像');