黑白图转RGB（Matlab）

SamplePath1 =  "C:\Users\LY\Desktop\green\";  %存储图像的路径
fileExt = '*.bmp';  %待读取图像的后缀名
%获取所有路径
files = dir(fullfile(SamplePath1,fileExt)); 
len = size(files,1);
for ii=1:len
    fileName = strcat(SamplePath1,files(ii).name);
    I=imread(fileName);
    I_r=zeros(size(I,1),size(I,2),3);
    I_g=zeros(size(I,1),size(I,2),3);
    I_b=zeros(size(I,1),size(I,2),3);
    I_r(:,:,1)=im2double(I(:,:,1));
    I_g(:,:,2)=im2double(I(:,:,1));
    I_b(:,:,3)=im2double(I(:,:,1));
    temp=strcat(files(ii).name);
    eval(['imwrite(I_r,''I',num2str(str2num(temp(1:end-4)), '%04d'),'_r.bmp'');']);
    eval(['imwrite(I_g,''I',num2str(str2num(temp(1:end-4)), '%04d'),'_g.bmp'');']);
    eval(['imwrite(I_b,''I',num2str(str2num(temp(1:end-4)), '%04d'),'_b.bmp'');']);
end

效果

 只保留了红色和绿色，蓝色不用已经删除