**5. Some example of interaction**

10 Will-be-set-by-IN-TECH

Fig. 2. The dominance function for the diphtong case (a) and the weights diagram (b) for the

Emotions can be considered as particular visemes, called emotional visemes. They must be "mixed" with the phonetic visemes to express an emotion during the facial animation. Such a process can be performed in two different ways. FaceGen can generate also facial modification to express an emotion, so a phonetic viseme can be modified using FaceGen to include an emotion. As result, different sets of modified phonetic visemes can be produced. Each of them are different both as type and intensity of a given emotion. Such a solution is very accurate but it requires an adequate amount of memory and time to create a large emotional/phonetic visemes database. The second approach considers a single emotional viseme whose mesh vertexes coordinate are blended with a viseme to produce a new keyframe. Even though such a solution is less accurate than the previous one, it is less expensive on the computational side, and allows to include and mix "on the fly" emotional and phonetic visemes at run-time.

Prosody contains all the information about the intonation and duration to be assigned to each phoneme in a sentence. In our talking head model, the prosody is provided by Espeak espeak (2010), a multilanguage and multiplatform tool that is able to convert the text into a .pho prosody file. The Talking Head is intrinsically synchronized with the audio streaming because the facial movements are driven by the .pho file, which determines the phoneme (viseme) and its duration. Espeak provides a variety of options to produce the prosody for the language and speech synthesizer to use. As an example it can generate a prosody control for the couple Italian/Mbrola, which is a speech synthesizer based on concatenation of diphones. It takes as

Fig. 3. The same of Fig.2 for the vowel-consonant case.

**4.3 The emotional talking head**

**4.4 Audio streaming synchronization**

diphthong case
