title: Stereovision and augmented reality for closed-loop control of grasping in hand prostheses.
abstract: OBJECTIVE
  Technologically advanced assistive devices are nowadays available to restore grasping, but effective and effortless control integrating both feed-forward (commands) and feedback (sensory information) is still missing. The goal of this work was to develop a user friendly interface for the semi-automatic and closed-loop control of grasping and to test its feasibility.
  
  
  METHODS
  We developed a controller based on stereovision to automatically select grasp type and size and augmented reality (AR) to provide artificial proprioceptive feedback. The system was experimentally tested in healthy subjects using a dexterous hand prosthesis to grasp a set of daily objects. The subjects wore AR glasses with an integrated stereo-camera pair, and triggered the system via a simple myoelectric interface.
  
  
  RESULTS
  The results demonstrated that the subjects got easily acquainted with the semi-autonomous control. The stereovision grasp decoder successfully estimated the grasp type and size in realistic, cluttered environments. When allowed (forced) to correct the automatic system decisions, the subjects successfully utilized the AR feedback and achieved close to ideal system performance.
  
  
  CONCLUSIONS
  The new method implements a high level, low effort control of complex functions in addition to the low level closed-loop control. The latter is achieved by providing rich visual feedback, which is integrated into the real life environment. The proposed system is an effective interface applicable with small alterations for many advanced prosthetic and orthotic/therapeutic rehabilitation devices.
authors.affiliation: Department of NeuroRehabilitation Engineering, Bernstein Focus Neurotechnology Göttingen, Bernstein Center for Computational Neuroscience, University Medical Center Göttingen, Georg-August University, D-37075 Göttingen, Germany.
authors.forename: Marko
authors.initials: M
authors.lastname: Markovic
authors.forename: Strahinja
authors.initials: S
authors.lastname: Dosen
authors.forename: Christian
authors.initials: C
authors.lastname: Cipriani
authors.forename: Dejan
authors.initials: D
authors.lastname: Popovic
authors.forename: Dario
authors.initials: D
authors.lastname: Farina
mesh_terms: D000465:Algorithms; D003627:Data Interpretation, Statistical; D004576:Electromyography; D056228:Feedback, Sensory; D006225:Hand; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D019736:Prostheses and Implants; D011474:Prosthesis Design; D012371:Robotics; D015348:Vision, Binocular / Q000502:physiology*