B Knappmeyer

The use of facial motion and facial form during the processing of identity

Previous research has shown that facial motion can carry information about age, gender, emotion and, at least to some extent, identity. By combining recent computer animation techniques with psychophysical methods, we show that during the computation of identity the human face recognition system integrates both types of information: individual non-rigid facial motion and individual facial form. This has important implications for cognitive and neural models of face perception, which currently emphasize a separation between the processing of invariant aspects (facial form) and changeable aspects (facial motion) of faces.

Automatic Synthesis of Sequences of Human Movements by Linear Combination of Learned Example Patterns

We present a method for the synthesis of sequences of realistically looking human movements from learned example patterns. We apply this technique for the synthesis of dynamic facial expressions. Sequences of facial movements are decomposed into individual movement elements which are modeled by linear combinations of learned examples. The weights of the linear combinations define an abstract pattern space that permits a simple modification and parameterization of the style of the individual movement elements. The elements are defined in a way that is suitable for a simple automatic resynthesis of longer sequences from movement elements with different styles. We demonstrate the efficiency of this technique for the animation of a 3D head model and discuss how it can be used to generate spatio-temporally exaggerated sequences of facial expressions for psychophysical experiments on caricature effects.

Using facial texture manipulation to study facial motion perception

For the creation of manipulated video footage, these extracted “texturemap movies” can now be automatically altered by standard image processing and video editing techniques in various ways like e.g., freezing, replacing or filtering parts of the texture, mixing texture parts from different sources or changing order and timing of “texture frames”. All manipulations to facial regions need to be defined only once on a reference head and texture for a specific experiment and can then be applied automatically to different recordings of different actors, because all head models are in correspondence to each other, saving a lot of manual setup work.