Joint Processing of Audio -Visual Information for the Recognition of Emotional Expressions in Human -Computer Interaction
"This thesis addresses the problem of detecting human emotional expressions by computer from the voice and facial motions of the user. The computer is equipped with a microphone to listen to the user's voice, and a video camera to look at the user. Prosodic features in the audio and facial motions exhibited on the face can help the computer make some inferences about the user's emotional state, assuming the users are willing to show their emotions. Another problem it addresses is the coupling between voice and the facial expression. Sometimes the user moves the lips to produce the speech, and sometimes the user only exhibits facial expression without speaking any words. Therefore, it is important to handle these two modalities accordingly. In particular, a pure ""facial expression detector"" will not function properly when the person is speaking, and a pure ""vocal emotion recognizer"" is useless when the user is not speaking. In this thesis, a complementary relationship between audio and video is proposed. Although these two modalities do not couple strongly in time, they seem to complement each other. In some cases, similar facial expressions may have different vocal characteristics, and vocal emotions having similar properties may have distinct facial behaviors."
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign