This looks, like filename is a cell string, containing file names:
info=dicominfo(filenames{1});
Then getting the sizes of the cell array is strange:
[rows, columns, numberOfColorChannels] = size(filenames);
I assume, the size of filenames is [1,1] or maybe a vector. But it is unlikely, that the list of file names has 3 dimensions. I assume, you do not mean the name of the files, but the contents of an imported file - maybe:
img = dicomread(filenames{1});
[rows, columns, numberOfColorChannels] = size(img);
The same applies for
Igray = rgb2gray(filenames); % Converting the name of the file?!?
else
Igray = filenames;
end
X(:,:,:,y) = im2uint16(dicomread(Igray{y})); % Fine: import the contents!
