Controlling Virtual Humans Using PDAs

The new breed of Personal Digital Assistants (PDA) and mobile phones have enough computing power to display 3D graphics. These new mobile devices (handhelds) have some other interesting communication and interaction possibilities as well. In this paper we explore the potential applications of 3D virtual humans inside mobile devices and the use of such handhelds as control interfaces to drive the virtual humans and navigate through their virtual environments

Low-latency compression of mocap data using learned spatial decorrelation transform

Due to the growing needs of human motion capture (mocap) in movie, video games, sports, etc., it is highly desired to compress mocap data for efficient storage and transmission. This paper presents two efficient frameworks for compressing human mocap data with low latency. The first framework processes the data in a frame-by-frame manner so that it is ideal for mocap data streaming and time critical applications. The second one is clip-based and provides a flexible tradeoff between latency and compression performance. Since mocap data exhibits some unique spatial characteristics, we propose a very effective transform, namely learned orthogonal transform (LOT), for reducing the spatial redundancy. The LOT problem is formulated as minimizing square error regularized by orthogonality and sparsity and solved via alternating iteration. We also adopt a predictive coding and temporal DCT for temporal decorrelation in the frame- and clip-based frameworks, respectively. Experimental results show that the proposed frameworks can produce higher compression performance at lower computational cost and latency than the state-of-the-art methods.Comment: 15 pages, 9 figure

Supporting Real-time Pda Interaction With Virtual Environment

Personal Digital Assistants (PDAs) are becoming more and more powerful with advances in technology and are expanding their applications in a variety of fields. This work explores the use of PDAs in Virtual Environments (VE). The goal is to support highly interactive bi-directional user interactions in Virtual Environments in more natural and less cumbersome ways. A proxy-based approach is adopted to support a wide-range of handheld devices and have a multi-PDA interaction with the virtual world. The architecture consists of three components in the complete system, a PDA, a desktop that acts as a proxy and Virtual Environment Software Sandbox (VESS), software developed at the Institute for Simulation and Training (IST). The purpose of the architecture is to enable issuing text and voice commands from PDA to virtual entities in VESS through the proxy. The commands are a pre-defined set of simple words such as \u27move forward\u27, \u27turn right\u27, \u27go\u27, and \u27stop\u27. These commands are matched at the proxy and sent to VESS as text in XML format. The response from VESS is received at the proxy and forwarded back to the PDA. Performance measures with respect to response time characteristics of text messages between PDA and proxy over Wi-Fi networks are conducted. The results are discussed with respect to the acceptable delays for human perception in order to have real-time interaction between a PDA and an avatar in virtual world

Actores sintéticos en tiempo real: Nuevas estructuras de datos y métodos para su integración en aplicaciones de simulación.

RESUMEN La forma más extendida de implementar una aplicación de simulación es mediante la utilización de un grafo de escena. Este tipo de estructura resulta muy adecuado para definir escenas estáticas, pero presenta serias carencias a la hora de representar estructuras articuladas, u objetos con comportamientos complejos. Ambas circunstancias se dan en el caso de los actores virtuales. Este trabajo define nuevas estructuras de datos y métodos que permiten integrar de una forma adecuada actores virtuales en una aplicación de simulación: 1-Se presentan dos nuevos tipos de nodos (Actor y Skeleton), que actúan como elemento modular para la definición y gestión de cualquier tipo de actor virtual. En el diseño de estos nodos se ha prestado especial atención a la estandarización, y la eficiencia computacional. 2-Se proponen técnicas que permiten solventar algunas carencias de los grafos de escena actuales a la hora de ser empleados con actores virtuales. Se actúa sobre el cuello de botella existente en relación con aplicación de matrices de transformación. Se define un nuevo método de gestión de culling específico para actores, es compatible con el tradicional, y actúa sobre los costes asociados a la gestión del comportamiento. Se define un método de gestión de nivel de detalle específico, que actúa simultáneamente sobre la geometría, la topología y el comportamiento, y se realiza un análisis sobre la forma en que los actores han de ser integrados en un sistema multiprocesador 3-Se describe una estructura de nombre ActorClass, que es independiente del grafo de escena y que se encarga de almacenar todas las informaciones de alto nivel que son compartidas por varios actores de la misma especie. Esta estructura es capaz de absorber futuras ampliaciones y permite realizar simulaciones macroscópicas. Con el objeto de demostrar la utilidad práctica de los resultados de este trabajo, se ha implementado una librería de programación y una arquitectura modular que actúan sobre la base de las estructuras y métodos descritos, y se ha desarrollado un ejemplo de su utilización que muestra en detalle todos los aspectos de la integración de actores virtuales en una aplicación de simulación ya existente. ____________________________________________________________________________________________________The Scene Graph is the most widespread method of implementation simulation applications. This kind of structure is a very convenient way to define static scenes, but it has serious drawbacks in representing articulated structures or objects with complex behaviours. Both circumstances are inherent in virtual actors. This thesis defines new data structures and methods permiting the adequate integratión of virtual actors in a simulatión application: 1. Two new kinds of nodes are presented (Actor and Skeleton). These nodes function as modular elements to define and manage all kinds of virtual actor. During the dessing process of this nodes a great attention was paid to standarization and computational efficience. 2. Special techniques are presented in order to solve problems in the current scene graphs: Working on the bottleneck that exists in relation to the transformation matrix process; Defining a new method of culling, specific to actors, that is compatible with the traditional, and considers the costs associated with the behaviour management; Defining a specific Level of Detail method, that works simultaneously with the geometry, the topology and the behaviour; Making an analisis of the technique to ingrate actors in a multiprocessor system. 3. A new structure, named ActorClass, is defined. This structure is independent of the scene graph and is responsible for storing all the high level information that is shared by several actors of the same species. This structure has the capability of assimilating future expansions, and supporting the definition of macroscopic simulations. In order to show the practical utility of the results of this work, a programming library and a modular architecture have been implemented on the basis of these proposed structures and methods. In addition, a practical sample sample has been developed, showing in detail all the aspects of the integratión of virtual actors in an existing simulation application