Processing motion capture data to achieve positional accuracy

In animating an articulated entity with motion capture data, if the reconst ruction is based on forward kinematics, there could be a large error in the end-effector position. The inaccuracy becomes conspicuous when the entity makes interactions with the environment or other entities. The frames at wh ich the end-effector position needs to be accurate are designated as "keyfr ames" (e.g., the impact moment in a punch). We present an algorithm that pr ocesses the original joint angle data to produce a new motion in which the end-effector error is reduced to zero at keyframes. The new motion should n ot be too much different from the original motion. We formulated the proble m as a constrained minimization problem so that the characteristics of the original joint angle data is optimally preserved during the enhancement ste ps. The algorithm was applied to several examples such as boxing, kicking, and catching motions. Experiments Drove that our algorithm is a valuable to ol to improve captured motion especially when the end-effector trajectory c ontains a special goal. (C) 1999Academic Press.