how to calculate visual information fidelity (VIF) of images

the following function doesnot work

function vif=vifvec(imorg,imdist);

% -----------COPYRIGHT NOTICE STARTS WITH THIS LINE------------ % Copyright (c) 2005 The University of Texas at Austin % All rights reserved. % % Permission is hereby granted, without written agreement and without license or royalty fees, to use, copy, % modify, and distribute this code (the source files) and its documentation for % any purpose, provided that the copyright notice in its entirety appear in all copies of this code, and the % original source of this code, Laboratory for Image and Video Engineering (LIVE, http://live.ece.utexas.edu) % at the University of Texas at Austin (UT Austin, % http://www.utexas.edu), is acknowledged in any publication that reports research using this code. The research % is to be cited in the bibliography as: % % H. R. Sheikh and A. C. Bovik, "Image Information and Visual Quality", IEEE Transactions on % Image Processing, (to appear). % % IN NO EVENT SHALL THE UNIVERSITY OF TEXAS AT AUSTIN BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, % OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF THIS DATABASE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF TEXAS % AT AUSTIN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. % % THE UNIVERSITY OF TEXAS AT AUSTIN SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED % WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE DATABASE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, % AND THE UNIVERSITY OF TEXAS AT AUSTIN HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. % % -----------COPYRIGHT NOTICE ENDS WITH THIS LINE------------ % %This is an implementation of the algorithm for calculating the %Visual Information Fidelity (VIF) measure (may also be known as the Sheikh %-Bovik Index) between two images. Please refer %to the following paper: % %H. R. Sheikh and A. C. Bovik "Image Information and Visual Quality" %IEEE Transactios on Image Processing, in publication, May 2005. %Download manuscript draft from http://live.ece.utexas.edu in the %Publications link % %This implementation is slightly differnet from the one used to report %results in the paper above. The modification have to do with using more %subands than those used in the paper, better handling of image boundaries, %and a window that automatically resizes itself based on the scale. % %Report bugfixes and comments to [e-mail] % %---------------------------------------------------------------------- % Prerequisites: The Steerable Pyramid toolbox. Available at % http://www.cns.nyu.edu/~lcv/software.html % %Input : (1) img1: The reference image % (2) img2: The distorted image (order is important) % %Output: (1) VIF te visual information fidelity measure between the two images

%Default Usage: % Given 2 test images img1 and img2, whose dynamic range is 0-255 % % vif = vifvec(img1, img2); % %Advanced Usage: % Users may want to modify the parameters in the code. % (1) Modify sigma_nsq to find tune for your image dataset. % (2) MxM is the block size that denotes the size of a vector used in the % GSM model. % (3) subbands included in the computation %========================================================================

M=3; subbands=[4 7 10 13 16 19 22 25]; sigma_nsq=0.4;

% Do wavelet decomposition. This requires the Steerable Pyramid. You can % use your own wavelet as long as the cell arrays org and dist contain % corresponding subbands from the reference and the distorted images % respectively. [pyr,pind] =buildSpyr(imorg, 4, 'sp5Filters', 'reflect1'); % compute transform org=ind2wtree(pyr,pind); % convert to cell array [pyr,pind] = buildSpyr(imdist, 4, 'sp5Filters', 'reflect1'); dist=ind2wtree(pyr,pind);

% calculate the parameters of the distortion channel [g_all,vv_all]=vifsub_est_m(org,dist,subbands,M);

% calculate the parameters of the reference image [ssarr, larr, cuarr]=refparams_vecgsm(org,subbands,M);

% reorder subbands. This is needed since the outputs of the above functions % are not in the same order vvtemp=cell(1,max(subbands)); ggtemp=vvtemp; for(kk=1:length(subbands)) vvtemp{subbands(kk)}=vv_all{kk}; ggtemp{subbands(kk)}=g_all{kk}; end

% compute reference and distorted image information from each subband for i=1:length(subbands) sub=subbands(i); g=ggtemp{sub}; vv=vvtemp{sub}; ss=ssarr{sub}; lambda = larr(sub,:);, cu=cuarr{sub};

    % how many eigenvalues to sum over. default is all.
    neigvals=length(lambda);

    % compute the size of the window used in the distortion channel estimation, and use it to calculate the offset from subband borders
    % we do this to avoid all coefficients that may suffer from boundary
    % effects
    lev=ceil((sub-1)/6);
    winsize=2^lev+1; offset=(winsize-1)/2;
    offset=ceil(offset/M);

    % select only valid portion of the output.
    g=g(offset+1:end-offset,offset+1:end-offset);
    vv=vv(offset+1:end-offset,offset+1:end-offset);
    ss=ss(offset+1:end-offset,offset+1:end-offset);

    %VIF
    temp1=0; temp2=0;
    for j=1:length(lambda)
        temp1=temp1+sum(sum((log2(1+g.*g.*ss.*lambda(j)./(vv+sigma_nsq))))); % distorted image information for the i'th subband
        temp2=temp2+sum(sum((log2(1+ss.*lambda(j)./(sigma_nsq))))); % reference image information
    end
    num(i)=temp1;
    den(i)=temp2;

end

% compuate VIF vif=sum(num)./sum(den);

Answer 1

[Mahmood Haithami]

Dear Sir: This is not build in function in MATLAB. There are missing functions So, no body can help you with that. HOWEVER FORTUNATELY... I traced down the author and downloaded his code. The code is attached. Just extract the zip folder and in MATLAB write

>> vif_value = vifvec(OriginalImage, DistortedImage); #gray scale images

Answer 2

[lenin]

dear sir, i have downloaded the zipfile and tried to run the code .

but i am getting the following error "Undefined function or variable 'buildSpyr'"

[Congmin Chen]

a toolbox named "matlabPyrTools" is needed