Frédéric Vexo

A wearable system for mobility improvement of visually impaired people

Degradation of the visual system can lead to a dramatic reduction of mobility by limiting a person to his sense of touch and hearing. This paper presents the development of an obstacle detection system for visually impaired people. While moving in his environment the user is alerted to close obstacles in range. The system we propose detects an obstacle surrounding the user by using a multi-sonar system and sending appropriate vibrotactile feedback. The system aims at increasing the mobility of visually impaired people by offering new sensing abilities.

An ontology of virtual humans: Incorporating semantics into human shapes

Most of the efforts concerning graphical representations of humans (Virtual Humans) have been focused on synthesizing geometry for static or animated shapes. The next step is to consider a human body not only as a 3D shape, but as an active semantic entity with features, functionalities, interaction skills, etc. We are currently working on an ontology-based approach to make Virtual Humans more active and understandable both for humans and machines. The ontology for Virtual Humans we are defining will provide the “semantic layer” required to reconstruct, stock, retrieve, reuse and share content and knowledge related to Virtual Humans.

Semantics-based representation of virtual environments

In this paper, we present an object representation based on the semantics and functionality of interactive digital items - virtual objects - within a Virtual Environment (VE). We consider every object participating in a VE application not only as a 3D shape, but as a dynamic entity with multiple visual representations and functionalities. This allows for dynamically scaling and adapting the objects geometry and functions to different scenarios. Some test applications are described to demonstrate the benefits of the semantics-based representation of interactive virtual environments, including autonomous characters and collaborative environments.

The mobile animator: interactive character animation in collaborative virtual environments

We have designed a mobile -PDA-based- interface for real-time control of virtual characters in multiuser semi-immersive virtual environments - using a large rear-projection screen. The proof-of-concept implementation we present shows the potential of handheld devices as powerful interfaces to virtual reality applications. This technique eliminates the display of floating menus and other widgets over the simulation screen. A brief discussion on the advantages and disadvantages of using a handheld for 3D interaction is presented as well.

Quantifying Effects of Exposure to the Third and First-Person Perspectives in Virtual-Reality-Based Training

In the recent years, usage of the third-person perspective (3PP) in virtual training methods has become increasingly viable and despite the growing interest in virtual reality and graphics underlying third-person perspective usage, not many studies have systematically looked at the dynamics and differences between the third and first-person perspectives (1PPs). The current study was designed to quantify the differences between the effects induced by training participants to the third-person and first-person perspectives in a ball catching task. Our results show that for a certain trajectory of the stimulus, the performance of the participants post3PP training is similar to their performance postnormal perspective training. Performance post1PP training varies significantly from both 3PP and the normal perspective.

Emotional face expression profiles supported by virtual human ontology

Expressive facial animation synthesis of human like characters has had many approaches with good results. MPEG‐4 standard has functioned as the basis of many of those approaches. In this paper we would like to lay out the knowledge of some of those approaches inside an ontology in order to support the modeling of emotional facial animation in virtual humans (VH). Inside this ontology we will present MPEG‐4 facial animation concepts and its relationship with emotion through expression profiles that utilize psychological models of emotions. The ontology allows storing, indexing and retrieving prerecorded synthetic facial animations that can express a given emotion. Also this ontology can be used a refined knowledge base in regards to the emotional facial animation creation. This ontology is made using Web Ontology Language and the results are presented as answered queries. Copyright

Haptic feedback in mixed-reality environment

The training process in industries is assisted with computer solutions to reduce costs. Normally, computer systems created to simulate assembly or machine manipulation are implemented with traditional Human-Computer interfaces (keyboard, mouse, etc). But, this usually leads to systems that are far from the real procedures, and thus not efficient in term of training. Two techniques could improve this procedure: mixed-reality and haptic feedback. We propose in this paper to investigate the integration of both of them inside a single framework. We present the hardware used to design our training system. A feasibility study allows one to establish testing protocol. The results of these tests convince us that such system should not try to simulate realistically the interaction between real and virtual objects as if it was only real objects.

Mental vision: a computer graphics teaching platform

We have developed a learning platform to simplify and improve teaching and practice of Computer Graphics for beginners and advanced students. Our goal is to offer a set of tools to help students having a better mental vision of the abstract notions introduced during the course. Our platform is composed by a pedagogical-oriented, intuitive and user-friendly graphic engine, offering a powerful amount of features with an extremely easy and comfortable interface, and a set of interactive and collaborative applications (called modules) to use during lessons and workshop sessions to present complex concepts in an easy and clear way. In this paper we expose how we have built our platform, what it offers and which role will play in our courses.

Advanced virtual reality technologies for surveillance and security applications

We present a system that exploits advanced Virtual Reality technologies to create a surveillance and security system. Surveillance cameras are carried by a mini Blimp which is tele-operated using an innovative Virtual Reality interface with haptic feedback. An interactive control room (CAVE) receives multiple video streams from airborne and fixed cameras. Eye tracking technology allows for turning the users gaze into the main interaction mechanism; the user in charge can examine, zoom and select specific views by looking at them. Video streams selected at the control room can be redirected to agents equipped with a PDA. On-field agents can examine the video sent by the control center and locate the actual position of the airborne cameras in a GPS-driven map. The PDA interface reacts to the users gestures. A tilt sensor recognizes the position in which the PDA is held and adapts the interface accordingly. The prototype we present shows the added value of integrating VR technologies into a complex application and opens up several research directions in the areas of tele-operation, Multimodal Interfaces, etc.

Telerehabilitation: controlling haptic virtual environments through handheld interfaces

This paper presents a telerehabilitation system for kinesthetic therapy (treatment of patients with arm motion coordination disorders). Patients can receive therapy while being immersed in a virtual environment (VE) with haptic feedback. Our system is based on a Haptic Workstation that provides force-feedback on the upper limbs. One of our main contributions is the use of a handheld device as the main interface for the therapist. The handheld allows for monitoring, adapting and designing exercises in real-time (dynamic VE). Visual contact with the patient is kept by means of a webcam.