Body expression in virtual environments

As technology improves, virtual reality interfaces based on body actions and expressions are becoming more and more important. In the domain of games, an evident application is the control of the hero by body actions. The robotics domain is another area where such an interface presents an attractive issue, especially in the tele-presence field. In this paper we discuss an action model along with a real-time recognition system and show how it may be used in virtual environment

Conferring human action recognition skills to life-like agents

Most of today's virtual environments are populated with some kind of autonomous life-like agents. Such agents follow a preprogrammed sequence of behaviours that excludes the user as a participating entity in the virtual society. In order to make inhabited virtual reality an attractive place for information exchange and social interaction, we need to equip the autonomous agents with some perception and interpretation skills. We present one skill: human action recognition. By opposition to human-computer interfaces that focus on speech or hand gestures, we propose a full-body integration of the user. We present a model of human actions along with a real time recognition system. To cover the bilateral aspect in human-computer interfaces, we also discuss some action response issues. In particular, we describe a motion management library that solves animation continuity and mixing problems. Finally, we illustrate our system with two examples and discuss what we have learne

Interacting with virtual humans through body actions

Since their inception, interactive virtual environments have not been able to interpret users' gestures. Researchers have investigated a few tentative solutions, but most of them concern a specific set of body parts like hands, arms, or facial expressions. However, when placing a participant in a virtual world to interact with synthetic inhabitants, it would be more convenient and intuitive to use body-oriented actions. To achieve this, we developed a hierarchical model of human actions based on fine-grained primitives. An associated recognition algorithm identifies simultaneous actions on the fl

Live participant's action recognition for virtual reality interactions

The recognition of daily human activities is a decisive interface component for more intuitive virtual reality (VR) interactions. In this paper, we describe a hierarchical model of body actions based on fine-grained action primitives. The associated recognition algorithm allows on-the-fly identification of simultaneous actions. Measurements highlight robustness to participants' variability and high detection rates when using the full potential of the action model. An example illustrates an interaction with a virtual character driven by the participant's action recognitio

Integration of motion control techniques for virtual human and avatar real-time animation

Real-time animation of virtual humans requires a dedicated architecture for the integration of different motion control techniques running into so-called actions. In this paper, we describe a software architecture called AGENTlib for the management of action combination. Considered actions exploit various techniques from keyframe sequence playback to inverse kinematics and motion capture. Two major requirements have to be enforced from the end user viewpoint: first, that multiple motion controllers can control simultaneously some parts or whole of the virtual human, and second, that successive actions result in a smooth motion flo

Real-time interactions with virtual agents driven by human action identification

The authors evaluate a multi-level action recognition algorithm for behavioral interactions in inhabited virtual world

Multi-level modeling and recognition of human actions involving full body motion

A multi-level model of human actions involving full body motion is proposed. Actions are considered as the combination of action primitives at different levels: motions of the center of mass, end effectors, and final postures of the virtual skeleton. The model is especially designed for fast action recognition from the input of the human motion at the joint leve

Versatile tuning of humanoid agent activity

Presents an integration framework for heterogeneous motion generators. The objective is to outline issues that are currently easily solved in the professional post-processing systems used in film and game production but which cannot be transposed “as-is” to real-time systems with autonomous agents. We summarise our approach for articulated agent modelling and their animation by combining heterogeneous motion generators, such as real-time motion capturing, key-framing, inverse kinematics and procedural walking generators. We propose an agent/action-oriented framework. Activity properties, such as action simultaneity and motion blending, spatial coherence, motion-flow update schemes, agent attachments and location corrections are the main topics handled by our generic animation framework. Numerous examples throughout the paper illustrate our approach and outline encountered problems and solutions or open research direction

Interaction in Virtual Worlds: Application to Music Performers

We present am odel for the representation of the interactions between virtual hum an figures and virtual objects in 3D virtual scenes. These interactions can depend on externally provided inform ation not being lim ited in their com plexity. The representationm odel for virtual hum ans ism odular and provides tools for representation of the interaction know-how pre-requisite.Tim ng constraints are relevant in thism odel and concurrency and synchronism are used to insure the adequacy of the resulting anim ations of virtual hum ans and associated interacted objects. Resulting gestures are derived from an adapted application of Inverse Kinem aticsm; hods. Keywords: Virtua Scenes, Virtua Hum ans, Virtua Objects, Interaction, Inverse Kinem atics, Musician Sim u ation. 1