Sylvain Chagué

Artanim · R&D

We present two experiments to assess the relative impact of different levels of body animation fidelity on plausibility illusion (Psi). The first experiment presents a virtual character that is not controlled by the user ( $n = 13$ ) while the second experiment presents a user-controlled virtual avatar ( $n = 24$ , all male). Psi concerns how rea...

In this paper, we investigate three forms of virtual reality (VR) content production and consumption. Namely, pre-rendered 360 stereoscopic video, full real-time rendered 3D scenes, and the combination of a real-time rendered 3D environment with a pre-rendered video billboard used to present the central elements of the scene. We discuss the advanta...

In this paper, we investigate three forms of virtual reality content production and consumption. Namely, 360 stereoscopic video, the combination of a 3D environment with a video billboard for dynamic elements, and a full 3D rendered scene. On one hand, video based techniques facilitate the acquisition of content, but they can limit the experience o...

Purpose To quantify shoulder motion during Codman pendulum exercises. Methods Shoulder kinematics were analyzed in 17 healthy volunteers using a validated biomechanical model coupling patient-specific imaging and motion capture. Participants were instructed to perform medio-lateral, antero-posterior and circular pendulum exercises. Glenohumeral (G...

Introduction : Il n’existe pas de consensus sur la meilleure méthode de réaliser une acromioplastie, notamment quant à la localisation et à l’étendue de la résection osseuse, qui dépendent de la morphologie de l'articulation scapulo-humérale. Hypothèse : Notre but est de déterminer si la planification de l’acromioplastie assistée par ordinateur aid...

Introduction There is no consensus on how to perform acromioplasty, particularly regarding the level and extent of bone resection, which depend on scapular and humeral morphologies. Hypothesis We aimed to determine whether computer-assisted acromioplasty planning helps surgeons remove impinging bone, reduce unnecessary resections, and improve shor...

Background To date, there is no consensus on when and how to perform acromioplasty during rotator cuff repair (RCR). We aimed to determine the volume of impinging bone removed during acromioplasty and whether it influences postoperative range of motion (ROM) and clinical scores after RCR. Methods Preoperative and postoperative computed tomography...

Purpose Rehabilitation is an important aspect of both non-operative and operative treatments of knee ligament tear. Posterior cruciate ligament (PCL) non-operative treatment consists of a step-by-step rehabilitation protocol and is well described. It goes from rest (phase I) to strengthening exercises (phase IV). More specific and high-intensity ex...

Background Augmented reality (AR) allows the surgeon to represent holographic patient‐specific anatomical information and surgical instruments on the physical world. To correctly superimpose virtual and physical objects, a hand‐eye calibration method for mapping the virtual and physical spaces was proposed. Methods Mathematical relationships betwe...

The aim of this study was to analyze the occurrence of rotator cuff impingement due to reduction of subacromial space height during complex shoulder motion to determine safety of sexual activities. The hypothesis was that such activities could be deleterious if not performed with precaution. To use a patient-specific 3D measurement technique coupli...

Purpose Recent technology advances in Augmented Reality (AR) is creating an opportunity for a paradigm shift in the field of Computer Assisted Surgery (CAS). Despite having the potential of being a promising technology in clinical applications, its accuracy, robustness, and performances under specific environmental conditions have not been fully i...

We present a visualization tool for human motion analysis in augmented reality. Our tool builds upon our previous work on joint biomechanical modelling for kinematic analysis, based on optical motion capture and personalized anatomical reconstruction of joint structures from medical imaging. It provides healthcare professionals with the in situ vis...

We present a visualization tool for human motion analysis in augmented reality. Our tool builds upon our previous work on joint biomechanical modelling for kinematic analysis, based on optical motion capture and personalized anatomical reconstruction of joint structures from medical imaging. It provides healthcare professionals with the in situ vis...

We describe a calibration procedure to track consumer Head Mounted Displays (HMD) using a 3rd party tracking solution. The calibration consists of registering the center of projection of the rendering hardware to a 3rd party tracked object attached to it, and is performed by matching motion datasets from the HMD built-in and 3rd party tracking solu...

Purpose: We present a computer-assisted planning solution "ArthroPlanner" for acromioplasty based on 3D anatomical models, computed tomography and joint kinematic simulations. Methods: In addition to a standard static clinical evaluation (anamnesis, radiological examination), the software provides a dynamic assessment of the shoulder joint by co...

Purpose: Shoulder strength training exercises represent a major component of rehabilitation protocols designed for conservative or postsurgical management of shoulder pathologies. Numerous methods are described for exercising each shoulder muscle or muscle group. Limited information is available to assess potential deleterious effects of individua...

The primary objective of this study was to compare radiological results including persistent subacromial impingement in a serie of patients operated from a postero-superior rotator cuff repair with or without a computer-assisted planning solution, called ArthroPlanner, for acromioplasty. As individual scapular anatomy and patient's expectations are...

When estimating knee kinematics from skin markers and stereophotogrammetry, multi-body optimization (MBO) has provided promising results for reducing soft tissue artefacts (STA), but can still be improved. The goal of this study was to assess the performance of MBO with subject-specific knee models at high knee flexion angles (up to 110°) against k...

Introduction Codman's pendular shoulder exercises have been widely used for decades as means of passively mobilizing the glenohumeral (GH) joint while not compromising recently injured or repaired tissues. Neurophysiological studies have confirmed the largely passive nature of the exercises, but no studies have actually shown that the exercises res...

Background Despite the fact that surgery is commonly used to treat glenohumeral instability, there is no evidence that such treatment effectively corrects glenohumeral translation. The purpose of this prospective clinical study was to analyze the effect of surgical stabilization on glenohumeral translation. Methods Glenohumeral translation was ass...

Background Shoulder strength training exercises represent a major component of rehabilitation protocols designed for conservative or post-surgical management of shoulder pathologies. Numerous methods are described for exercising each shoulder muscle or muscle group. Limited information is available to assess potential deleterious effects of individ...

The feeling of synchrony is fundamental for most social activities and prosocial behaviors. However, little is known about the behavioral correlates of this feeling and its modulation by intergroup differences. We previously showed that the subjective feeling of synchrony in subjects involved in a mirror imitation task was modulated by objective be...

Despite the fact that surgery is commonly used to treat glenohumeral instability, there is no evidence that such treatment effectively corrects glenohumeral translation. The purpose of this prospective clinical study was to analyze the effect of surgical stabilization on glenohumeral translation. Glenohumeral translation was assessed in 11 patients...

Real Virtuality is a multiuser immersive platform combining motion capture with virtual reality (VR) headsets: users can freely move within the physical space while virtually visiting a virtual world and interacting with 3D objects or other users using the sense of touch.

People performing actions together have a natural tendency to synchronize their behavior. Consistently, people doing a task together build internal representations not only of their actions and goals, but also of the other people performing the task. However, little is known about which are the behavioral mechanisms and the psychological factors af...

Shoulder pain and injury are common in tennis players. The precise causes for such pain remain unclear. Impingement at critical tennis positions and glenohumeral instability have never been dynamically evaluated in vivo. The purpose of this study was to evaluate the different types of impingement and stability during tennis movements. Laboratory st...

Embodying an avatar in virtual reality (VR) experiences is very important to reach a high feeling of presence. This is even more important in a collaborative VR scenario where multiple users must interact to achieve a certain task. In this paper, we present a new VR platform combining 3D body scanning, motion capture and head mounted display allowi...

Purpose: Rotator cuff and labral lesions in tennis players could be related to posterosuperior internal impingement or subacromial impingement during tennis serve. However, it is unknown which of these impingements are responsible for the lesions found in the tennis player's shoulder. Moreover, there is a lack of validated noninvasive methods and...

Real Virtuality is a multi-user immersive system that combines motion capture with VR headsets. Users can freely move within the physical space while virtually visiting the recreated interior of a pharaoh's tomb and interacting with 3D objects or other users.

Strengthening of shoulder muscles in rehabilitation protocols and sport practice can be achieved by a wide range of different exercises. Very limited objective data is at disposal to emit recommendations for design of a training protocol that aims at minimizing subacromial impingement, stress on the articular cartilages or labrum and excessive tend...

Purpose: Total Hip Arthroplasty (THA) aims to restore patient mobility by providing a pain-free and stable artificial joint. A successful THA depends on the planning and its execution during surgery. Both tasks rely on the experience of the surgeon to understand the complex biomechanical behavior of the hip. We investigate the hypothesis that a com...

Patients undergoing total hip arthroplasty are increasingly younger and have a higher demand concerning hip range of motion. To date, there is no clear consensus as to the amplitude of the "normal hip" in everyday life. It is also unknown if the physical examination is an accurate test for setting the values of true hip motion. The purpose of this...

Background: Measuring dynamic in vivo shoulder kinematics is crucial to better understanding numerous pathologies. Motion capture systems using skin-mounted markers offer good solutions for non-invasive assessment of shoulder kinematics during dynamic movement. However, none of the current motion capture techniques have been used to study translat...

Relative risk of impingement and joint instability during sexual activities after total hip arthroplasty (THA) has never been objectively investigated. Hip range of motion necessary to perform sexual positions is unknown. A motion capture study with two volunteers was performed. 12 common sexual positions were captured and relevant hip joint kinema...

One of the main goals in populating the virtual environments (VEs) with human body models is to increase the visual realism of the simulation. Population created with a template model cloning technique is perceived by the viewer as a synthetic crowd. To increase the degree of the visual realism, mainly the characters are generated with various body...

One of the main goals in populating the virtual environments (VEs) with human body models is to increase the visual realism of the simulation. Population created with a template model cloning technique is perceived by the viewer as a synthetic crowd. To increase the degree of the visual realism, mainly the characters are generated with various body...