“…One approach for objectively measuring the performance of a synthesizer is to re-synthesize a set of test sentences for which the original visual speech is available and measure the distance between key points located about the face [6], [17], [44], [46], [52], [53], within the parameters used to model the visual speech [20], [23], [43], [54]- [56], or in the image pixels [12]. Although this approach is intuitive and simple to compute, there are two main limitations.…”