课程学习——灰度图像转换为彩色图像_ChouMaRenShen的博客_灰度图像转换为彩色效果

代码：

function R=gray2rgb(img1,img2)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%　This Program converts a gray image ro RGB image based on the colors of the destination image. The　better the destination image match with the source gray image, the better the coloring will be. The program takes some time  as the searching time is high. You can decrease the searching time by taking　only samples from the used color image but quality may decrease. U can use jittered sampling for improving running speed. % 
%  You can use also use the attahed test images, Use the following combinations for better result　nature1.jpg(as img1) and nature2.jpg(as img2) or test1.jpg(as img1) and test2.jpg (as img2)　%
%　Usage: gray2rgb('nature1.jpg','nature2.jpg');  %

%  Authors : Jeny　Rajan , Chandrashekar　P.S %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% img1 - Source Image  (gray image)   
% img2 - Selected color image for coloring the gray image. 
tic
 clc;
 warning off;
 imt=imread(img1);
 ims=imread(img2);
 [sx sy sz]=size(imt);
 [tx ty tz]=size(ims);
 if sz~=1
     imt=rgb2gray(imt);
 end
 if tz~=3
     disp ('img2 must be a color image (not indexed)');
 else
     imt(:,:,2)=imt(:,:,1);
     imt(:,:,3)=imt(:,:,1);

 % Converting to ycbcr color space
     nspace1=rgb2ycbcr(ims);
     nspace2= rgb2ycbcr(imt);

    ms=double(nspace1(:,:,1));
     mt=double(nspace2(:,:,1));
     m1=max(max(ms));
     m2=min(min(ms));
     m3=max(max(mt));
     m4=min(min(mt));
     d1=m1-m2;
     d2=m3-m4;
 % Normalization
     dx1=ms;
     dx2=mt;
     dx1=(dx1*255)/(255-d1);
     dx2=(dx2*255)/(255-d2);
     [mx,my,mz]=size(dx2);
 %Luminance Comparison
     disp('Please wait..................');
     for i=1:mx
         for j=1:my
              iy=dx2(i,j);
              tmp=abs(dx1-iy);
              ck=min(min(tmp));
              [r,c] = find(tmp==ck);
              ck=isempty(r);
              if (ck~=1)            
                  nimage(i,j,2)=nspace1(r(1),c(1),2);
                  nimage(i,j,3)=nspace1(r(1),c(1),3);
                  nimage(i,j,1)=nspace2(i,j,1);           
             end
          end
      end
     rslt=ycbcr2rgb(nimage)
     figure,imshow(uint8(imt));
     figure,imshow(uint8(rslt));
     R=uint8(rslt);
     toc
 end  
function R=gray2rgb(img1,img2)
%%%