Motion Editing with the State Feedback Dynamic Model

In this paper, a novel motion editing tool, called the state feedback dynamic model, is proposed and demonstrated for the animators to edit the pre-existing motion capture data. The state feedback dynamic model is based on the linear time-invariant system (LTI). Compared with previous works, by this model, the animators need only modify a few keyframes manually, and the other frames can be adjusted automatically while preserving as much of the original quality as possible. It is a global modification on motion sequence. More important, the LTI model derives an explicit mapping between the high-dimensional motion capture data and low-dimensional hidden state variables. It transforms a number of possibly correlated joint angle variables into a smaller number of uncorrelated state variables. Then, the motion sequence is edited in state space, and which considers that the motion among joints is correlated. It is different from traditional methods which consider each joint as independent of each other. Finally, an effective algorithm is also developed to calculate the model parameters. Experimental results show that the generated animations through this method are natural and smooth.