Sir, i need to hide the text in color image without converting it to grey scale.This is the code i did so far.I am using syndrome trllis coding here.

clc
close all
clear all
clear stack

Prompt user to select the file

[fn,pn] = uigetfile('*.bmp;*.jpg;*.png','Select your original image');
I = imread([pn,fn]);
% I=imread('lena.jpg');

if size(I,3)==3
I=rgb2gray(I);
end
[r,c]=size(I);
r=r-rem(r,8);
c=c-rem(c,8);
I=imresize(I,[r,c]);
figure,imshow(I);title('cover image');
pause(2)
[row,col]=size(I);
img=I;
%secret message to be embedded
txt1=input('Enter secret text  ','s');
N1=numel(txt1);
txt1=repmat(txt1, 1, 1); %Just to make text big for causing distortion in cover image
%  txt1=repmat(txt1, 1, r*c/(10*8*N1)) %Just to make text big for causing distortion in cover image
N=numel(txt1);
txt=txt1-0;
Lr=dec2bin(txt,8);
Lrm1 = reshape(Lr,1,N*8);
Lrm=uint8(abs(Lrm1(:)-48));
% Lrm=[1; 0;1]
figure(1)
%%Embedding
%%Standard quantization table
qTable=[16 11 10 16 24 40 51 61;
        12 12 14 19 26 58 60 55;
        14 13 16 24 40 57 69 56;
        14 17 22 29 51 87 80 62;
        18 22 37 56 68 109 103 77;
        24 35 55 64 81 104 113 92;
        49 64 78 87 103 121 120 101;
        72 92 95 98 112 100 103 99];

%DCT    
rev=zeros(row,col);
x=zeros(row,col);
for m=1:row/8
    for n=1:col/8
        s1=img((m-1)*8+1:m*8,(n-1)*8+1:n*8);
        d1=dct2(s1);
        q1=floor(d1./qTable+0.5);
        r1=q1.*qTable;
        x((m-1)*8+1:m*8,(n-1)*8+1:n*8)=r1;  
    end
end
% dct_a=x %future
figure,imshow(uint8(x))
title('Quantized DCT Image');

% x=dct_a;
%%x-xb 
x1=x(x~=0);
si= sign(x1);
x1=abs(x1)+eps  ;
pho =x1.^-1;
%xb
m=max(x1);
N=ceil(log2(m));
bi=dec2bin(x1,N);
xb=bi(:,N);
xb=uint8(abs(xb-48));

n = numel(xb);  %size of the cover
h = 10;         %constraint height - default is 10 - drives the complexity/quality tradeof
m = numel(Lrm); % number of message bits

cover =   uint8(xb);
message = uint8(Lrm);
cost =    pho;

   stego = stc_embd_new(cover, message, cost);

% [dist, stego] = stc_embed(cover, message, cost, h); % embed message
% message1 = stc_extract(stego, m, h); % extract check
% disp('extract check');
% all(message == message1)
% 
bi(:,N)=char(48+uint8(stego));
x1=bin2dec(bi);
x1=x1.*si;
x(x~=0)=x1;
% dct_b=x

% x=dct_b;
figure,imshow(uint8(x))
title('stego DCT Image');
%IDCT
nimg=zeros(row,col);
for m=1:row/8
    for n=1:col/8
        q1=x((m-1)*8+1:m*8,(n-1)*8+1:n*8);

          k1=idct2(q1);
          nimg((m-1)*8+1:m*8,(n-1)*8+1:n*8)=k1; %uint8(k1);
      end
  end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5
figure, imshow(uint8(nimg));title('stego image');
imwrite(uint8(nimg),'Stego.jpg');
PSNR=psnr(img,nimg)

%%Extraction

%DCT  
x=zeros(row,col);
for m=1:row/8
    for n=1:col/8
        s1=nimg((m-1)*8+1:m*8,(n-1)*8+1:n*8);
        d1=dct2(s1);
        q1=round(d1);
        x((m-1)*8+1:m*8,(n-1)*8+1:n*8)=q1;  
    end
end
% dct_c=x
figure,imshow(uint8(x))
title('rounded DCT Image');

% x=dct_c;
%%x-xb 

x1=x(x~=0);
si= sign(x1);
x1=abs(x1)  ;

%xb
m=max(x1);
N=ceil(log2(m));
bi=dec2bin(x1,N);
xb=bi(:,N);
xb=uint8(abs(xb-48));

h = 8;         %constraint height - default is 10 - drives the complexity/quality tradeof
m = numel(Lrm); % number of message bits

message3 = stc_extrct_new(xb, m);

message2=char(message3+48);
Lrr = reshape(message2,[],8);
txt2=bin2dec(Lrr);

rectxt=txt2';
disp('Recovered secret message');
disp(char(rectxt));

Answer 1

[Walter Roberson]

if size(I,3)==3
  G = I(:,:,2);
  B = I(:,:,3);
  I = I(:,:,1);
else
  G = I;
  B = I;
end

[r,c]=size(I);
r=r-rem(r,8);
c=c-rem(c,8);
I=imresize(I,[r,c]);
G = imresize(G,[r,c]);
B = imresize(B,[r,c]);

then go ahead with your existing embedding code. After you have embedded, reconstruct the color image using

I = cat(3,I,G,B);

[alphyros mathew]

Thank you sir