spread spectrum watermarking for hiding data on a image

i have written the code for spreading a water,ark on a image, based on spread spectrum watermarking. i am not getting the recovered watermark properly. since the programe is running succesfully and not showing any errors, i cudnt find out reason for not getting the output. please help me to rewrite the same. program is shown below.

clc;
clear all;
close all;
 k=.0009;            % set the gain factor for embeding
 % read in the cover object
cover_object=double(dicomread('189.dcm'));
cover_object = uint8(255*mat2gray(cover_object));
figure, imshow(cover_object,[])
 title('input Image')

    % determine size of watermarked image
  Mc=size(cover_object,1);    %Height
   Nc=size(cover_object,2);    %Width
   [fname,path]=uigetfile({'*.txt';'*.*'},'selct file');
  path=[path fname];

A=importdata(path);
x=A(1);
for i=2:size(A,1)
    x=strcat(x,'\n');
    x=strcat(x,A(i));
end
x=x{1};
c=dec2bin(x,8);
y=c(1,:);
for i=2:size(c,1)
    y=strcat(y,c(i,:));
end
for i=1:size(y,2)
    z(i)=double(y(i));
end
z(z(:)==48)=0;
z(z(:)==49)=1;
disp(z)
message=z;
 [e f]=size(message);
 %message=im2bw(message);
 figure, imshow(message,[])
title('watermark message Image')
message_vector=message(:);
 x=length(message_vector);
 els = {'p',[-0.125 0.125],0};

lshaarInt = liftwave('haar','int2int');
lsnewInt = addlift(lshaarInt,els);

[LL,LH,HL,HH] = lwt2(double(cover_object),lsnewInt);
[LL1,LH1,HL1,HH1] = lwt2(double(HH),lsnewInt);
% figure,imshow(HH,[]);
% title(' HH band');

% figure,imshow(LL1,[]);
% title(' LL1 band');
 w=0;
 [m n]=size(LL1);
pn=zeros(x,m*n);
 % add pn sequences to HH 
for kk=1:x
     pn_sequence_h=round(rand(1,m*n));
     pn(kk,:)=pn_sequence_h;
         if (message_vector(kk) == 1)
             w=w+pn_sequence_h;

       end
  end
   host_vector=HH1(:);
    Iw=host_vector+k*w';
   wm=buffer(Iw,n);
  %   figure, imshow(wm,[])
  %  title(' band after watermarking')
     % perform IDWT
  HH =  uint8(ilwt2(LL1,LH1,HL1,wm,lsnewInt));
  watermarked_image=uint8(ilwt2(LL,LH,HL,double(HH),lsnewInt));

    % convert back to uint8
   watermarked_image_uint8=uint8(watermarked_image);

   % display watermarked image
   figure,imshow(watermarked_image_uint8,[])

   % extraction part

    title('Watermarked Image')
     els = {'p',[-0.125 0.125],0};
  % 
   lshaarInt = liftwave('haar','int2int');
   lsnewInt = addlift(lshaarInt,els);

   [LL,LH,HL,HH] = lwt2(double(watermarked_image_uint8),lsnewInt);
   [LL1,LH1,HL1,HH1] = lwt2(double(HH),lsnewInt);

     iw=HH1(:);
     for kk=1:x
         if (sign(corr2(iw',pn(kk,:))) < 0)
           message_vector(kk)=0;
       else
                    message_vector(kk)=1;

       end
    end
  if  (message_vector== message')
      disp('same watermark')
       else 
         disp('differentwm')

end