Proc. SPIE. 5292, Human Vision and Electronic Imaging IX
KEYWORDS: Visual process modeling, Data modeling, Databases, Computer simulations, Data processing, Human vision and color perception, Virtual reality, Motion models, Solid modeling, Vision-based navigation
Intelligent virtual human is widely required in computer games, ergonomics software, virtual environment and so on. We present a vision-based behavior modeling method to realize smart navigation in a dynamic environment. This behavior model can be divided into three modules: vision, global planning and local planning. Vision is the only channel for smart virtual actor to get information from the outside world. Then, the global and local planning module use A* and
D* algorithm to find a way for virtual human in a dynamic environment. Finally, the experiments on our test platform (Smart Human System) verify the feasibility of this behavior model.
Object-order volume rendering algorithms play important part in many visualization applications for their excellent performances. Though many volume rendering algorithms have been proposed during the past two decades, most of them are image-order algorithms. Splatting, one of the classical object-order algorithms, suffers from several kinds of aliasing artifacts for inaccuracy reasons. A much accurate object-order volume rendering algorithm is presented in this paper. By defining a set of data structures to serve as two step reconstruction lookup tables, together with using a simple voxel traversal and resample strategy, the new algorithm can not only get rid of inaccuracy of traditional splatting, but also have the features including high cache hit rate, easy to implement of parallelism and high speedup from pre-processing.
This paper described the design of the DAVRS system. This system not only provides a 3D design environment for architects, but also realizes distributed collaboration between the designers through the internet. The DAVRS system used Java3D to construct virtual sense, XML to pocket sense controlling data, and Java MQ to transmit data. Moreover, a three-level distributed collaboration model is designed in order to confirm the safety of collaboration based on internet.
Volume rendering has been a key technology in the visualization of data sets from various disciplines. However, real-time volume rendering of large scale data sets is still a challenging field due to the vast memory, bandwidth and computational requirements. In this paper, to visualize small to medium scale data set in real-time, we first proposed a new kind of volume rendering graphic processor based on object-order splatting algorithm in which flexible transfer function configuration and software optimization such as early opacity termination and transparent voxel occlusion can be achieved. At the same time, the processor also integrates an eight-way interleaved memory system and an efficient address calculation module to accelerate the voxel traversal process and maintain high cache hit rate. Multiple parallel rendering pipelines embedded also can achieve local parallelism on board. Second, in order to render large scale data sets, a real-time and general-purpose volume rendering architecture is also presented in this paper. By utilizing graphic processors on PC clusters, large scale data sets can be visualized resulted from the high parallel speedup among graphic processors.
Virtual human is widely used in educational, entertainment, and 3D game software. In this paper, the subsumption architecture, which is popular in robotics, is employed to make a two-level control model. With this model, virtual human can realize collision-free navigation in a dynamic environment. As collision avoidance is realized in the 0-level layer, path planning is completed in the 1-level layer. Finally, an experiment was done in our human animation platform. And the result shows that this control model can guide digital actor navigate collision-freely in the environment with dynamic and static obstacles.
An architecture of distributed virtual reality system is brought forward in this paper. It's based on a C/S system model, and employs a centralized-and-distributed data distribution model. This data distribution model can efficiently realize concurrency control, and easily ensure the data consistency. It also employs a four-layered structure based on Message Queue to accomplish the collaboration management. This structure is platform-independent and very flexible for further extending and upgrading. In this paper, we'll introduce the C/S system model and the centralized-and-distributed data distribution model, and then discuss in detail how the four-layered structure based on Message Queue realizes the collaboration management.