Plz help in dwt-svd wwtaermarking-its imp

Plz help me in my dessertation work.

I have written this dwt-svd code in matlab.it is running bt giving a very low psnr value.plz help me for wat the errors are.... also my mail id is [e-mail]

%-------------------------
%Embedding 
%-------------------------
clear;
clc

img= imread('lena_gray_256.bmp');
img=imresize(img,[256 256]);
cover_img=img;

img=double(img);
[M,N]=size(img);

%[Uimg,Simg,Vimg]=svd(img);
%Vimg_temp=Vimg;

% read watermark
 img_wat= imread('baboon.bmp');
 img_wat=imresize(img_wat,[256 256]);
img_wat=double(img_wat);
[x y]=size(img_wat);

[ca1,ch1,cv1,cd1]=dwt2(img,'haar');

[u1 s1 v1]=svd(ca1); %svd each subband (DWT 1 level)
[u2 s2 v2]=svd(ch1); %from cover image
[u3 s3 v3]=svd(cv1);
[u4 s4 v4]=svd(cd1);

[ca2,ch2,cv2,cd2]=dwt2(img_wat,'haar');

[u11 s11 v11]=svd(ca2); %svd each subband (DWT 1 level)
[u22 s22 v22]=svd(ch2); %from cover image
[u33 s33 v33]=svd(cv2);
[u44 s44 v44]=svd(cd2);

%[wu ws wv]=svd(img_wat); %svd visual watermark

ws1 = s1 + (s11 * 0.05); %Modify the singular values of the cover
ws2 = s2 + (s22 * 0.05); %image in each subband with singular
ws3 = s3 + (s33 * 0.05); %values of the visual watermark
ws4 = s4 + (s44 * 0.05);

%to obtain the 4 sets of modified DWT coefficients :
wca1=(u1*ws1*v1);
wch1=(u2*ws2*v2);
wcv1=(u3*ws3*v3);
wcd1=(u4*ws4*v4);

% perform IDWT CAA1 = idwt2(cA22,cH2,cV2,cD2,'haar',[RcA1,CcA1]);

Wimg= idwt2(wca1,wch1,wcv1,wcd1,'haar',[M,N]);

Wimg=uint8(Wimg);

figure(1)
imshow(uint8(img));
title('The Original Image')

figure(2)
imshow(uint8(img_wat));
title('The Watermark ')

figure(3)
imshow(uint8(Wimg));
title('The Watermarked Image')

% display psnr of watermarked image
psnr=psnr(cover_img,Wimg,M,N),
PSNR=10*(log10(psnr))
%MSE=mse(img,Wimg,M,N);
%MSE=10*(log10(MSE))

%mse=mean(squeeze(sum(sum((double(img)-double(Wimg)).^2))/(M*N)));
%PSNR=10*log10(255^2./mse);
msg=sprintf('\n\n-------------------------\nWatermark by SVD  PSNR=%fdB\n-----------------------------\n\n', PSNR);
    disp(msg);