Automatic Keyframing of Human Actions for Computer Animation

This paper presents a novel human action model based on key-frames which is suitable for animation purposes. By defining an action as a sequence of time-ordered body posture configurations, we consider that the most characteristic postures (called key-frames) are enough for modeling such an action. As characteristic postures are found to correspond to low likelihood values, we build a human action eigenspace, called aSpace, which is used to estimate the likelihood value for each posture. Once the key-frames have been found automatically, they are used to build a human action model called p–action by means of interpolation between key-frames. This parameterized model represents the time evolution of the human body posture during a prototypical action, and it can be used for computer animation. As a result, realistic and smooth motion is achieved. Furthermore, realistic virtual sequences involving several actions can be automatically generated.