Machine Perception Laboratory

The output of the face detector is scaled to 90x90 and fed directly to the facial expression analysis system (see Figure 1). The system is essentially the same as the one used for Automatic FACS coding. First the face image is passed through a bank of Gabor filters at 8 orientations and 9 scales (2-32 pixels/cycle at 0.5 octave steps). The filterbank representations are then channeled to a classifier to code the image in terms of a set of expression dimensions. We have found support vector machines to be very effective for classifying facial expressions (Littlewort et al., in press, Bartlett et al., 2003).