Catálogo de publicaciones - libros

To keep spatial awareness in virtual multilevel building, navigator should understand the spatial structure of space. Mental representation of spatial structure in a virtual cylindrical room was investigated in present experiments. Participants first observed two static views of space in which the two viewpoints were on the same vertical plane but with different heights, and then either judged the relative direction of object in the first experiment or egocentrically pointed out the direction of object in the second experiment. The results suggested that the orientation-dependent representation of spatial structure was created even though participants could learn the space from two different viewpoints lying on the vertical dimension of space.

This paper proposes a novel planar walking algorithm for the Virtual Walking Machine (VWM), which is a dual foot platform type locomotion interface. Unlike existing algorithms used for VWM, the proposed algorithm utilizes a constraint relationship between two platforms as well as position control. Experiments on the VWM show that the proposed planar walking algorithm can generate straight and turning motions which are smoother and collision-free.

On the basis of an established individualized face 3D model, this paper implements a new facial pose detection based on face model plane. The new method, by utilizing the feature point correspondence between model plane and model image, can compute the three parameters of face pose angle and effect model display, representing a simple interactive system of virtual face pose estimation. Experiments show that proposed algorithm, simple and highly automated, can accurately and effectively detect facial pose information and display pose changes of virtual models.

In this paper, we propose a prototype system, which deals with dynamic and huge graphic data on heterogeneous platforms, thus enabling clients to manage their shared virtual world in their hardware/software environment. Through the proposed system, users can experience the same virtual world in different interface metaphors: the keyboard of PC, a virtual control using a handheld MR (Mixed Reality), and the key button/stylus of PDA. Since we consider various service styles to various clients, first of all, we need to adjust the system’s service level to low-end devices having lower performance. Therefore, we processed two kinds of considerations, data simplification, and the virtual control interface using handheld MR method to overcome limitations related to data transmission and data input.

Today, hand-held computing and media devices are commonly used in our everyday lives. This paper assesses the viability of hand-held devices as effective platforms for “virtual reality.” Intuitively, the narrow field of view of hand-held devices is a natural candidate factor against achieving an effective immersion. In this paper, we show two ways of manipulating the visual field of view (perceived or real), in hopes of overcoming this factor. Our study has revealed that when a motion-based interaction was used, the FOV perceived by the user (and presence) for the small hand-held device was significantly greater than the actual. The other method is to implement dynamic rendering in which the FOV is adjusted depending on the viewing position and distance. Although not formally tested, the second method is expected to bring about higher focused attention (and thus immersion) and association of the visual feedback with one’s proprioception. The paper demonstrates the distinct possibility of realizing reasonable virtual reality even with devices with a small visual FOV and limited processing power through multimodal compensation.

We propose a new rendering system for large-scale, 3D geometic data that can be used with web-based content management systems (CMS). To achieve this, we employed a geometry hierarchical encoding method “QSplat” and implemented this in a Java and JOGL (Java bindings of OpenGL) environment. Users can view large-scale geometric data using conventional HTML browsers with a non-powerful CPU and low-speed networks. Further, this system is independent of the platforms. We add new functionalities so that users can easily understand the geometric data: Annotations and HTML Synchronization. Users can see the geometric data with the associated annotations that describe the names or the detailed explanations of the particular portions. The HTML Synchronization enables users to smoothly and interactively switch our rendering system and HTML contents. The experimental results show that our system performs an interactive frame rate even for a large-scale data whereas other systems cannot render them.

TV-Anytime metadata is being widely accepted as a metadata standard format that describes digital TV contents. It provides a wide spectrum of information of TV programs such as program information, program groups, program schedules, program reviews, program segments, user preferences, etc. These metadata are structured in a large hierarchical XML document. For efficiency, the metadata is split into a set of smaller pieces of metadata fragments that can be transmitted and accessed independently over a broadcast network. In this paper, we propose a fragment-based XML data indexing and querying scheme for efficient processing of TV-Anytime metadata. The experimental results show that the proposed scheme performs better than the generic XML data indexing and querying methods.

We have been developing a new type of human-computer interface, myokinetic synthesizer (MyoKinSynthesizer), using electromyography (EMG) signals. It enables a user to select virtual instruments and to control its properties such as volume and tone without any position or force sensors. The virtual marimba system emulates the basic properties of the real instrument by producing a sound depending on in which of eight zones and how hard the user is hitting. The virtual drum set is composed of 4 different virtual drums controlled by arms and legs. We used a three-layer neural network to estimate position and force of the forearm from EMG signals. After training the neural network and obtaining appropriate weights, the subject was able to control the movement of virtual avatar and to play virtual instruments. The system was destined to be used as a demonstration of VR entertainment and music therapy rehabilitation.

This article describes a new contribution culling method for the view-dependent real-time rendering of complex huge urban scenes. As a preprocessing step, the view frustum culling technique is used to cull away invisible objects that are outside the view frustum. For the management of the levels-of-detail, we subdivide the image regions and construct a weighted quadtree. The weight of each quadtree node is defined as the sum of weights of all objects contained in the node or its child nodes. The weight of an object is proportional to the view space area of the projected object as well as the distance from the viewpoint. Hence, large buildings in the far distance are not always culled out since their contributions to the rendering quality can be larger than those of near small buildings. We tested the proposed method by applying it to render a huge number of structures in our metropolitan section which is currently under development. Experimental results showed that the proposed rendering method guarantees real-time rendering of complex huge scenes.

This paper presents our simple and easy to use method to obtain a 3D textured model. Our algorithm consists of building a measurement-based 2D metric map which is acquired by laser range-finder, texture acquisition/stitching and texture-mapping to corresponding 3D model. The algorithm is applied to 2 cases which are corridor and space that has the four walls like room of building. The proposed algorithm can be applied to 2D/3D model-based remote surveillance system through WWW. The application terminals of this environment model for interactive VR that we consider are PC, PDA and Mobile phone. Especially, this paper introduces a case of service on WIPI-based mobile phone.