MATLAB: Compare each image with another

Question

As suggested by @Image Analyst to read images from the system to workspace I am using his code he answered on a different question.

folder = 'D:\My Pictures\whatever'
filePattern = fullfile(folder, '*.jpg');
f=dir(filePattern)
files={f.name}
for k=1:numel(files)
  fullFileName = fullfile(folder, files{k})
  cellArrayOfImages{k}=imread(fullFileName)
end

Now I want to compare each image in my workspace to other image using the score ssim(). I have to categorize those images into 4 groups dependent on the score (0.7,0.9) using ifelse and also then save them into different folders in my system which would be great. Please let me know how can I do this which would also not slow the system as I have lots of images. Thanks in advance.

Answer 1

I suggest you don't store all the images in a cell array because you might run out of memory if you have a lot of them. I'd just use a double for loop:

numImages = numel(files);
allSsim = ones(numImages, numImages);
for k = 1 : numImages - 1
    fullFileName1 = fullfile(folder, files{k});
    image1 = imread(fullFileName1);
    for k2 = k + 1 : numImages
         fullFileName2 = fullfile(folder, files{k2});
         image2 = imread(fullFileName2);
         allSsim(k, k2) = ssim(image1, image2) % Compute ssim
         allSsim(k2, k) = allSsim(k, k2); % Make symmetric.
    end
end