Mario Gutiérrez

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.

Emerging Web graphics standards and technologies

Migrating computer graphics to the Web poses several problems, but with new standards and technology advances, graphics applications can balance latency and bandwidth constraints with image quality. The paper discusses Web graphics standards, distributed virtual environments and virtual humans.

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.

Semantic Virtual Environments with Adaptive Multimodal Interfaces

We present a system for real-time configuration of multimodal interfaces to Virtual Environments (VE). The flexibility of our tool is supported by a semantics-based representation of VEs. Semantic descriptors are used to define interaction devices and virtual entities under control. We use portable (XML) descriptors to define the I/O channels of a variety of interaction devices. Semantic description of virtual objects turns them into reactive entities with whom the user can communicate in multiple ways. This article gives details on the semantics-based representation and presents some examples of multimodal interfaces created with our system, including gestures-based and PDA-based interfaces, amongst others.

Conducting a virtual orchestra

The virtual orchestra is a multimodal system architecture based on complex 3D sound environment processing and a compact user interface. The system architecture supports high-performance sound content for VR (virtual reality) applications, and the user controls the performance with a magnetically tracked handheld device. The objective of this work is to give music amateurs the opportunity to conduct a group of musicians and produce a new kind of multimedia experience. To explore this idea, the authors developed a semi-immersive virtual reality system, based on a large projection screen, designed to create an entertaining multimedia experience for nonexpert users. They decided to implement a music performance simulator, a VR system where several virtual characters play different musical instruments and adapt their performance according to the users instructions.

Mediators: virtual haptic interfaces for tele-operated robots

This work develops the concept of mediators: virtual interfaces with haptic feedback for teleoperation. Our approach is to replace physical operator interfaces by fully parameterizable adaptive virtual interfaces. Mediators open new possibilities for multimodal feedback for control interfaces. We apply mediators in the context of teleoperation of robots. The implemented prototype shows the feasibility of using virtual haptic interfaces to drive robots remotely.

Magic wand and the Enigma of the Sphinx

Abstract This paper presents an evaluation of the benefits and user acceptance of a multimodal interface in which the user interacts with a game-like interactive virtual reality application “The Enigma of the Sphinx”. The interface consists of a large projection screen as the main display, a “magic wand”, a stereo sound system and the users voice for “casting spells”. We present our conclusions concerning “friendliness” and sense of presence, based on observations of more than 150 users in a public event.

A MPEG-4 virtual human animation engine for interactive web based applications

This paper presents a novel, MPEG-4 compliant animation engine (body player). It has been designed to synthesize virtual human full-body animations in interactive multimedia applications for the web. We believe that a full-body player can provide a more expressive and interesting interface than the use of animated faces only (talking heads). This is one of the first implementations of a MPEG-4 animation engine with deformable models (it uses the MPEG-4 Body Definition Parameters and Deformation Tables). Several potential applications are overviewed. This software tool was developed in the framework of the IST-INTERFACE European project.

Reflex Movements for a Virtual Human: A Biology Inspired Approach

This paper presents the results of a method to produce autonomous animation of virtual humans. In particular, the proposedmethodology is focused on the autonomous synthesis of non-voluntary gestures such as reflexes and subtle movements which provide a noticeable impression of realism and naturalness. The final goal of this technique is to produce virtual humans with a more spontaneous, non pre-programmed behaviour. For the moment, the technique is applied to the synthesis of reflex movements of the arm, in reaction to thermic stimuli. Nevertheless, a general architecture is outlined.