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Abstract
Most conventional computer-aided navigation sys- tems assist the surgeon visually by tracking the position of an ancillary and by superposing this position into the 3D preoperative imaging exam. This paper aims at adding to such navigation systems a device that will guide the surgeon towards the target, following a complex preplanned ancillary trajectory. We propose to use tactile stimuli for such guidance, with the design of a vibrating belt. An experiment using a virtual surgery simulator in the case of skull base surgery is conducted with 9 naive subjects, assessing the vibrotactile guidance effectiveness for complex trajectories. Comparisons between a visual guidance and a visual+tactile guidance are encouraging, supporting the relevance of such tactile guidance paradigm.

Abstract
This paper examines the effect of adding haptic force cues (simulated inertia, compensation of gravity) during 3D-path following in large immersive virtual reality environments. Thirty-four participants were asked to follow a 3D ring-on-wire trajectory. The experiment consisted of one pre-test/control bloc of twelve trials with no haptic feedback; followed by three randomized blocs of twelve trials, where force feedbacks differed. Two levels of inertia were proposed and one level compensating the effect of gravity (No-gravity). In all blocks, participants received a real time visual warning feedback (color change), related to their spatial performance. Contrariwise to several psychophysics studies, haptic force cues did not significantly change the task performance in terms of time completion or spatial distance error. The participants however significantly reduced the time passed in the visual warning zone in the presence of haptic cues. Taken together, these results are discussed from a psychophysics and multi-sensory integration point of view.

http://www.techniques-ingenieur.fr/book/re131/apprendre-a-ecrire---apports-des-interfaces-haptiques.html

Introduction
L'utilisation d'interfaces haptiques contrôlées par ordinateurs peut aider les enfants ou les adultes à améliorer la fluidité de leur écriture. Les recherches actuelles révèlent l'utilité de la réalité virtuelle et augmentée dans la réalisation de tâches quotidiennes.

http://cat.inist.fr/?aModele=afficheN&cpsidt=20615897

Summary
Haptic guidance by a force feedback device is a recent and original technology which provides additional proprioceptive cues during visuo-motor learning tasks. The effects of two types of haptic guidances - control in position (HGP) or in force (HGF) - on visuo-manual tracking ("following") of trajectories are still under debate. In children, studies analyzed the effects of using HPG to train the fluency of writing cursive letters. Results showed that the fluency of handwriting for all letters was higher after the HGP training session than after the control training session: The movements of the hand were faster, exhibited less velocity peaks and the children lifted the pen less frequently during handwriting. In adults, three training techniques of haptic guidance (HGP, HGF or control condition, NHG, without haptic guidance) were evaluated. Results showed that the use of HGF globally improves the fluency of the visuo-manual tracking of trajectories (two Arabic and two Japanese-inspired letters and ellipses) while no significant improvement was found for HGP or NHG. These results show that the addition of haptic information, probably encoded in force coordinates, play a crucial role on the learning of new trajectories.

Abstract
Background: Learning to perform new movements is usually achieved by following visual demonstrations. Haptic guidance by a force feedback device is a recent and original technology which provides additional proprioceptive cues during visuomotor learning tasks. The effects of two types of haptic guidances-control in position (HGP) or in force (HGF) - on visuomanual tracking ("following") of trajectories are still under debate. Methodology/Principals Findings: Three training techniques of haptic guidance (HGP, HGF or control condition, NHG, without haptic guidance) were evaluated in two experiments. Movements produced by adults were assessed in terms of shapes (dynamic time warping) and kinematics criteria (number of velocity peaks and mean velocity) before and after the training sessions. Trajectories consisted of two Arabic and two Japanese-inspired letters in Experiment 1 and ellipses in Experiment 2. We observed that the use of HGF globally improves the fluency of the visuo-manual tracking of trajectories while no significant improvement was found for HGP or NHG. Conclusion/Significance: These results show that the addition of haptic information, probably encoded in force coordinates, play a crucial role on the visuo-manual tracking of new trajectories.

http://doi.acm.org/10.1145/1152399.1152418

Abstract

This paper presents a system that allows patients and physicians to experience better communication during medical consultations using Augmented Reality (AR) technology. This AR system can superimpose augmentations (i.e., human body components) onto the real patient's body. This annotated information would form the cornerstone for collaborative work between the two actors. We focus on the advantages of projector-based technology and the ARToolKit. Our technique, based on thermal markers (i.e., using human body temperature as a source of information) is used for tracking the location of pain in the patient through the projected augmentations. The second aim of using thermal markers is to protect the patient's privacy. The required calibration method between thermal-camera and projector is also presented. The feasibility of the system is demonstrated through development of a complete application.

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Last update: 07/11/10