10. The apparatus of claim 7 , wherein the processor: determines a discriminative power for each of a plurality of AUs based on statistical data; selects a set of AUs representing each of a plurality of emotion labels, based on the discriminative power for each of the plurality of AUs; and stores the selected set of AUs associated with each of the plurality of emotion labels as AU strings.
10. The apparatus of claim 7 , wherein the processor: determines a discriminative power for each of a plurality of AUs based on statistical data; selects a set of AUs representing each of a plurality of emotion labels, based on the discriminative power for each of the plurality of AUs; and stores the selected set of AUs associated with each of the plurality of emotion labels as AU strings. 11. The apparatus of claim 10 , wherein the selected set of AUs associated with each of the plurality of emotion labels are stored as the AU strings in a matrix.