Online motion retargetting

Abstract

This paper presents a method to retarget the motion of a character to another in real time. The technique is based on inverse rate control, which computes the changes in joint angles corresponding to the changes in end-effector position. While tracking the multiple end-effector trajectories of the original subject or character, our online motion retargetting also minimizes the joint angle differences by exploiting the kinematic redundancies of the animated model. This method can apply a captured motion to another anthropometry so that it can perform slightly different motion, while preserving the original motion characteristics. Because the above is done online, a real-time performance can be mapped to other characters. Moreover, if the method is used interactively during motion capture session, the feedback of retargetted motion on the screen provides more chances to get satisfactory results. As a by-product, our algorithm can be used to reduce measurement errors in restoring captured motion. The data enhancement improves the accuracy in both joint angles and end-effector positions. Experimental results show that our retargetting algorithm preserves high-frequency details of the original motion quite accurately. Copyright © 2000 John Wiley & Sons, Ltd.