Multiple Sphere Fits to 3D matrix

I need to be able to do multiple sphere fits to a 3D matrix. The 3D matrix is created from a series of 2D images. This 3D matrix is supposed to represent a sort of mesh-like material, and I want to fit spheres to estimate pore size. The code that I am using is the Sphere Fit (Least squared) by Alan Jennings, but I think this only fits one sphere to the data. How would I go about fitting spheres everywhere there might be a 'pore'?

I have attached the current code that I have below. Essentially, I am taking a series of 2D images, resizing them, so they can be made into a 3D matrix.

% pre-allocate (or pre-size) a matrix to store all 1001 2D images
numImages = 1001;
allImages = uint8(zeros(maxnumrow,maxnumcol,numImages));


for k = 1 : numImages
	% OPTION 2: Create an image filename, and read it in to a variable called imageData.
	jpgFileName = strcat('image', num2str(k), '.jpg');
    if isfile(jpgFileName)
		imageData = imread(jpgFileName);
        %resize all images to same size
        imresize(imageData,[maxnumrow maxnumcol], 'bilinear');
        % load the data from file
        dataStruct = load(imageData);
        % save the data to the 3D array
        allImages(:,:,k) = dataStruct.(char(fields(dataStruct)));
	else
		fprintf('File %s does not exist.\n', jpgFileName);
    end
end

sphereFit(allImages)

Thank you.