MATLAB: Comparing single image with many images

Question

I have written a matlab function that enables me to get the name of image from user and compare it with the existing images and display if it matches or not..

    function matchin
    handles = guidata(gcbo);
    set(handles.h_text,'String','performing matching...');
    [image1, pathname]= uigetfile('*.bmp','Open An Fingerprint image');
    Directory = fullfile ('F:','matlab','bin');
    D = dir(fullfile(Directory,'*.bmp'));
    set(handles.h_text,'String','matching complete....');
    for i = 1:numel(D)
       if strcmp(image1,D(i).name)
           disp('matched');
       else       
           disp('not matched');
       end
    end

the above code checks if the file name exists but i now want to compare the images itself instead of the file name. How can I do that?Please help..

Regards

Priya

Answer 1

How do you define a match? If all pixels are the same, and only one single pixel is different by only 1 gray level? Is that a match or not a match? If you say that's not a match, then first just compare the number of rows, columns, and color channels. Then if all those match, simply subtract the image (after converting to floating point) and look for any non-zero values with nnz();

diffImage = single(image1) - single(image2);
imagesMatch = nnz(diffImage(:)) == 0;