Non-Photorealistic Computer Graphics Library

Evaluation of Real-World and Computer-Generated Stylized Facial Expressions

Author(s): Christian Wallraven, Heinrich H. Bülthoff, Douglas W. Cunningham, Jan Fischer, Dirk Bartz.
Article: ACM Transactions on Applied Perception (TAP), Vol. 4, No. 3, pp. 1544--3558, November, 2007.
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Abstract:
The goal of stylization is to provide an abstracted representation of an image that highlights specific types of visual information. Recent advances in computer graphics techniques have made it possible to render many varieties of stylized imagery efficiently making stylization into a useful technique, not only for artistic, but also for visualization applications. In this paper, we report results from two sets of experiments that aim at characterizing the perceptual impact and effectiveness of three different stylization techniques in the context of dynamic facial expressions. In the first set of experiments, animated facial expressions are stylized using three common techniques (brush, cartoon, and illustrative stylization) and investigated using different experimental measures. Going beyond the usual questionnaire approach, these experiments compare the techniques according to several criteria ranging from subjective preference to task-dependent measures (such as recognizability, intensity) allowing us to compare behavioral and introspective approaches. The second set of experiments use the same stylization techniques on real-world video sequences in order to compare the effect of stylization on natural and artificial stimuli. Our results shed light on how stylization of image contents affects the perception and subjective evaluation of both real and computer-generated facial expressions.