Can PSNR be infinity

I am doing thesis on Image watermarking using DWT(Discrete Wavelet Transforms) and encryption using random permutations. After applying various attacks such as rotation, scaling, croping,contrast, I am getting PSNR between Original watermark and Decrypted watermark equal to Infinity.

Can this Possible????????????????

I am attaching my code and picture along with this..................

[i11,i12]=uigetfile('*.jpg;*.png;*.tif;*bmp');
i12=strcat(i12,i11);  %String Concatenation
i1=imread(i12);       %Image is read and stored in the variable i1 
i1= imresize(i1,[256 256]); %resizing the image with new dimensions as 512*512
[l,m,n]=size(i1);     %displaying the dimensions of Image
P1=im2double(i1);     %Convert the integer image into double image as it gives more Precised value
%Did 3 level DWT
[F1,F2]= wfilters('haar', 'd');
[LL,LH,HL,HH] = dwt2(P1,'haar','d'); %One Level DWT
[LL1,LH1,HL1,HH1] = dwt2(LL,'haar','d'); %Two Level DWT
[LL2,LH2,HL2,HH2] = dwt2(LL1,'haar','d') %Three Level DWT
[a,b]= uigetfile('*.jpg;*.png;*.tif;*bmp'); %Fetching the Image to be watermarkedXXXXXXXXXX%
b= strcat(b,a);   %String Concatenation
c=imread(b);     %Image is read and stored in the variable c
c= imresize(c,[64 64]); %resizing the image with new dimensions as 64*64
[p,q,r]=size(c); %displaying the dimensions of Image
%%%%%%%%%Cipher watermark%%%%%%%%%%%%%%%%%%%%%
scrambleOrder = randperm(p*q);
redChannel = c(:, :, 1);
greenChannel = c(:, :, 2);
blueChannel = c(:, :, 3);
redChannel = redChannel(scrambleOrder);
greenChannel = greenChannel(scrambleOrder);
blueChannel = blueChannel(scrambleOrder);
redChannel = reshape(redChannel, [p,q]);
greenChannel = reshape(greenChannel, [p,q]);
blueChannel = reshape(blueChannel, [p,q]);
s = cat(3, redChannel, greenChannel, blueChannel);
%converting the encrypted image into one level dwt
 f= im2double(s);
 [F1,F2]= wfilters('haar', 'd');
 [LL11,LH11,HL11,HH11] = dwt2(f,'haar','d'); %one level dwt of the encrypted image
 %LL11 = imresize(LL11,[64 64]);
 k = LL2 + 0.001*LL11.*LL2;
 Watermarkedimage_level1= idwt2(k,LH2,HL2,HH2,'haar'); %reconstruction of the watermark level3
 Watermarkedimage_level2=idwt2(Watermarkedimage_level1,LH1,HL1,HH1,'haar'); %reconstruction of the watermark level2
 Watermarkedimage_final=idwt2(Watermarkedimage_level2,LH,HL,HH,'haar');   %reconstruction of the watermark level1
%%%%%%%%%%%%%%%rotation attack%%%%%%%%%%%%%%%%%%%%%%%
 %data = clipboard('pastespecial') 
 J = imresize(Watermarkedimage_final,[220 140]);
 [N1 L1 B1] = size(J);
 %axis tight;
 %%%%%%%PSNR and MSE between Host Image and Watermarked
 %%%%%%%Image%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%Recovery of watermark fromm attacked image%%%%%%%%%%%%%%%%%%%%%%%%%%
 [a b c1 d]=dwt2(J,'haar','d');
 [aa bb cc dd]=dwt2(a,'haar','d');
 [aaa bbb ccc ddd]=dwt2(aa,'haar','d');
 aaa = imresize(aaa,[N1/3 L1/3]);
 LL2 = imresize(LL2,[N1/3 L1/3]);
 Recovered_watermark = [(aaa ./LL2)-1]./0.001;
 %imshow(Recovered_watermark);
 Recovered_watermark1 = imresize(Recovered_watermark,[32 32]);

   Wavelet_reconstruction=idwt2(Recovered_watermark1,LH11,HL11,HH11,'haar');
   [u v z] = size(Wavelet_reconstruction); 
   %scrambleOrder1 = randperm(u*v);
   %%%%%%%%%%Decryption of Watermark%%%%%%%%%%%
   recoverOrder = zeros([u*v], 2);
   recoverOrder(:, 1) = 1 : (u*v);
   recoverOrder(:, 2) = scrambleOrder;
   newOrder1 = sortrows(recoverOrder, 2);
   newOrder = newOrder1(:,1);
   redChannel = redChannel(newOrder);
   greenChannel = greenChannel(newOrder);
   blueChannel = blueChannel(newOrder);
   redChannel = reshape(redChannel, [u, v]);
   greenChannel = reshape(greenChannel, [u, v]);
   blueChannel = reshape(blueChannel, [u, v]);
   D = cat(3, redChannel, greenChannel, blueChannel);
   s= im2double(s);
   squaredErrorImage = (c-D).^ 2;
      MSE=sum(sum(squaredErrorImage)) / (p* q)
      MaxI=1;   %maX INDICATES THE Maximum Value of the Pixles
      PSNR=10*log10((MaxI^2)/MSE)
      channelToCorrelate = 1;  % Use the red channel.
      correlationOutput = normxcorr2(D(:,:,1), c(:,:, channelToCorrelate));
      [rows, columns, numberOfColorBands] = size(correlationOutput);
      [maxCorrValue, maxIndex] = max(abs(correlationOutput(:)))
      channelToCorrelate = 2;  % Use the green channel.
      correlationOutput = normxcorr2(D(:,:,1), c(:,:, channelToCorrelate));
      [rows, columns, numberOfColorBands] = size(correlationOutput);
      [maxCorrValue, maxIndex] = max(abs(correlationOutput(:)))
      channelToCorrelate = 3;  % Use the green channel.
      correlationOutput = normxcorr2(D(:,:,1), c(:,:, channelToCorrelate));
      [rows, columns, numberOfColorBands] = size(correlationOutput);
      [maxCorrValue, maxIndex] = max(abs(correlationOutput(:)))
      subplot(3, 3, 1);imshow(i1);title('Message Image');
      subplot(3, 3, 2);imshow(c);title('Watermark image');
      subplot(3, 3, 3);imshow(s);title('Encrypted Watermark');
      subplot(3,3,4);imshow(Watermarkedimage_final);title('Watermarked Final');
      subplot(3, 3, 5);imshow(J);title('Scaled Watermarked Image');
      subplot(3, 3, 6);imshow(D);title('Decrypted Watermark');
      figure;surf(correlationOutput);title('correlationOutput');
   %%%%%%%PSNR and MSE between Host Image and Watermarked
      %%%%%%%Image%%%%%%%%%%%%%%%%%%%%
      %squaredErrorImage = (P1 - J) .^ 2;
      %%MSE=sum(sum(squaredErrorImage)) / (l * m)
      %MaxI=1;   %maX INDICATES THE Maximum Value of the Pixles
      %PSNR=10*log10((MaxI^2)/MSE)
      %%%%%%%%%%%%%PSNR and MSE between Encrypted and Extracted
      %%%%%%%%%%%%%Image%%%%%%%%%%%%%%%%%%%%
      %i3= im2double(i3);
      %squaredErrorImage = (s - Wavelet_reconstruction).^ 2;
      %MSE=sum(sum(squaredErrorImage)) / (p* q)
      %MaxI=1;   %maX INDICATES THE Maximum Value of the Pixles
      %PSNR=10*log10((MaxI^2)/MSE)
      %%%%%%%PSNR and MSE between watermark and Decrypted
      %%%%%%%Image%%%%%%%%%%%%%%%%%%%%%%%%

Answer 1

[Walter Roberson]

Yes, PSNR is infinity if the two images being compared are exactly the same.

[amira fauzey]

can i ask? My original image PSNR value is infinity is it correct?and my MSE value of original image is 0.original image means before i add noise to the image

[Walter Roberson]

Correct, if you compare two identical images, the PSNR is infinity and the MSE is 0.