No need to mess with the complication of cell arrays, simply index to subsample, resize, and then use "<" (less than operator).
data = randi(99, 192,192); % Sample data
[rows, columns] = size(data);
thresholds = data(2:3:end, 2:3:end); % Get centers of 3x3
% Make same size as data
thresholds = imresize(thresholds, [rows, columns], 'nearest');
% Apply threshold.
out = data > thresholds;
