MATLAB: How to compare the saved names of two images stored in different folders

comparing two images in separate foldersretrieving image names

I have 12 input images in the inputImages folder with names 001_in.png, 002_in.png ….. 012_in.png. Also I have the ground truths of these images 001_GT.png, 002_GT.png … 012_GT.png in another folder named GroundTruth. I want to read and display these 12 images and for each of these 12 images, I have to calculate the PSNR value with respect to the ground truth stored in the GroundTruth folder. How will I get the ground truth for a particular input image ? Here's my code. I have tried to retrieve the image names and compare them. But, I am getting name1 = * , name 2 = * , last= 1×0 empty char array. 
location1='G:\MTech\InputImages\*.png';
ds1=imageDatastore(location1)
while(hasdata(ds1))
    I=read(ds1);
    figure,imshow(I),title('Input Image');
    [filepath1,name1,ext1] = fileparts(location1) 
    underlineLocation1 = strfind(name1, '_')
    first = name1(1:underlineLocation1-1)   %Getting the image name upto underscore
    location2='G:\MTech\GroundTruth\*.png';
    ds2=imageDatastore(location2)
    while(hasdata(ds2))
        ref=read(ds2);
        figure,imshow(ref),title('Ground Truth');
        [filepath2,name2,ext2] = fileparts(location2)
        underlineLocation2 = strfind(name2, '_')
        last = name2(1:underlineLocation2-1)
        if first==last
            [peaksnr, snr] = psnr(I, ref);  
            fprintf('\n The Peak-SNR value of final output is %0.4f', peaksnr);
        end
    end    
end

Best Answer

I don't think imageDatastore particularly helps in this case. Something like this:
P1 = 'G:\MTech\InputImages';
P2 = 'G:\MTech\GroundTruth';
for k = 1:12
    F1 = sprintf('%03u_in.png',k);
    F2 = sprintf('%03u_GT.png',k);
    im = imread(fullfile(P1,F1));
    rf = imread(fullfile(P2,F2));
    [peaksnr,snr] = psnr(im,rf);
    fprintf('\n The Peak-SNR value of final output is %0.4f', peaksnr);
end
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