title: Musculoskeletal-see-through mirror: computational modeling and algorithm for whole-body muscle activity visualization in real time.
abstract: In this paper, we present a system that estimates and visualizes muscle tensions in real time using optical motion capture and electromyography (EMG). The system overlays rendered musculoskeletal human model on top of a live video image of the subject. The subject therefore has an impression that he/she sees the muscles with tension information through the cloth and skin. The main technical challenge lies in real-time estimation of muscle tension. Since existing algorithms using mathematical optimization to distribute joint torques to muscle tensions are too slow for our purpose, we develop a new algorithm that computes a reasonable approximation of muscle tensions based on the internal connections between muscles known as neuronal binding. The algorithm can estimate the tensions of 274 muscles in only 16 ms, and the whole visualization system runs at about 15 fps. The developed system is applied to assisting sport training, and the user case studies show its usefulness. Possible applications include interfaces for assisting rehabilitation.
authors.affiliation: Department of Mechano-Informatics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. murai@ynl.t.u-tokyo.ac.jp
authors.forename: Akihiko
authors.initials: A
authors.lastname: Murai
authors.forename: Kosuke
authors.initials: K
authors.lastname: Kurosaki
authors.forename: Katsu
authors.initials: K
authors.lastname: Yamane
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Nakamura
mesh_terms: D000465:Algorithms; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D004576:Electromyography / Q000295:instrumentation / Q000379:methods; D026241:Exercise Movement Techniques; D006801:Humans; D008954:Models, Biological; D053580:Muscle Strength; D009129:Muscle Tonus; D018482:Muscle, Skeletal / Q000502:physiology*; D055096:Optical Devices