Usability of multiviewpoint images for spatial interaction in projection-based display systems

In a common application scenario, large screen projection-based stereoscopic display systems are not used by a single user alone, but are shared by a small group of people. Using multiviewpoint images for multiuser interaction does not require special hardware and scales transparently with the number of colocated users in a system. We present a qualitative and quantitative study comparing usability and interaction performance for multiviewpoint images to non-head-tracked and head-tracked interaction for ray-casting selection and in-hand object manipulation. Results show that while direct first-person interaction in projection-based displays without head-tracking is difficult or even completely impractical, interaction with multiviewpoint images can produce similar or even better performance than fully head-tracked interaction. For ray-casting selection, interaction with multiviewpoint images is actually up to 10 percent faster than head-tracked interaction. For in-hand object manipulation in a simple docking task, multiviewpoint interaction performs only about 6 percent slower than fully head-tracked interaction     

Large dynamic tiled display system implementation and application

The Journal of Supercomputing - Advances in computer technology have led to growing demand for large high-resolution screens in environments such as large plazas, window displays and smart homes....     

Cost-effective haptic-based networked virtual environments with high-resolution tiled display

In this paper, a haptic-based NVE (networked virtual environment) supporting high-resolution tiled display is proposed with a resource management scheme for future home applications such as a haptic-based networked game. Although NVEs with haptic interaction and immersive display have been developed in previous studies, they usually require expensive system configurations. In order to implement a cost-effective system, our proposed design includes a tiled display supporting high-resolution with several low-cost LCDs. The display nodes of the tiled display also have low processing and storage resource requirements because they only need to handle display-ready pixels received from the application node. The proposed resource management scheme, called as an object-based display scheme, reduces the resource requirements of the application node that would otherwise require significant resources to manage all the display nodes and to provide a user with haptic feedback. The proposed scheme segments graphic scenes into several pixelated virtual objects and assigns different frame rates to each object according to the interest of user. Experimental results confirm that the proposed scheme reduces the required network bandwidth and appropriately assigns the limited processing resources to graphic and haptic renderings for a high-level visual and haptic quality.     

GPU rendering for tiled multi-projector autostereoscopic display based on chromium

In this paper, a GPU-based high-resolution multiview rendering approach (HRMVRA) is presented and incorporated into Chromium, and then a tiled multi-projector autostereoscopic display system (TMPADS) based on HRMVRA is constructed to provide an immersing 3D perception and a compelling sense of presence without the need of glasses for viewers. HRMVRA renders the multiview images in real time in only one pass, though the traditional multiview rendering approaches based on Chromium render the multiviews in multiple passes. The hardware of the autostereoscopic display system consists of a front-projection screen that covers an area of 360×160 square centimeters, twenty four projectors and thirteen computers connected with the gigabit Ethernet. TMPADS is well scalable since both the resolution and the number of the rendered views are configurable. It is shown by the experiments that HRMVRA has more than five times performance of the traditional high-resolution multiview parallax rendering based on Chromium. Most existing single-view OpenGL applications (e.g., some games like Quake III) can run directly on TMPADS without any source-code modification or re-compiling.     

改进的多投影仪显示墙几何校正技术

针对传统几何校正的不足,提出一种改进的几何校正的方法,只需少许人工干预就能很高精度的完成几何校正.介绍一种相机自动定位和拍照的方法,避免人工调整相机位置的繁琐工作,实现相机控制的自动化;提出一种基于递归的去除图片公共噪声区域算法,更精确地识别出特征点;通过临近的特征点,使用平行四边形插值算法与最小二乘法曲线拟合算法对被遮挡住的特征点坐标进行估计.实验结果表明,相机控制方法提高了几何校正的自动化程度,去噪算法提高了识别特征点的精度,平行四边形插值算法可以很好地对被遮挡的特征点坐标进行估计.     

Garuda: a scalable tiled display wall using commodity PCs

Cluster-based tiled display walls can provide cost-effective and scalable displays with high resolution and a large display area. The software to drive them needs to scale too if arbitrarily large displays are to be built. Chromium is a popular software API used to construct such displays. Chromium transparently renders any OpenGL application to a tiled display by partitioning and sending individual OpenGL primitives to each client per frame. Visualization applications often deal with massive geometric data with millions of primitives. Transmitting them every frame results in huge network requirements that adversely affect the scalability of the system. In this paper, we present Garuda, a client-server-based display wall framework that uses off-the-shelf hardware and a standard network. Garuda is scalable to large tile configurations and massive environments. It can transparently render any application built using the Open Scene Graph (OSG) API to a tiled display without any modification by the user. The Garuda server uses an object-based scene structure represented using a scene graph. The server determines the objects visible to each display tile using a novel adaptive algorithm that culls the scene graph to a hierarchy of frustums. Required parts of the scene graph are transmitted to the clients, which cache them to exploit the interframe redundancy. A multicast-based protocol is used to transmit the geometry to exploit the spatial redundancy present in tiled display systems. A geometry push philosophy from the server helps keep the clients in sync with one another. Neither the server nor a client needs to render the entire scene, making the system suitable for interactive rendering of massive models. Transparent rendering is achieved by intercepting the cull, draw, and swap functions of OSG and replacing them with our own. We demonstrate the performance and scalability of the Garuda system for different configurations of display wall. We also show that the server and network loads grow sublinearly with the increase in the number of tiles, which makes our scheme suitable to construct very large displays.     

Tele-immersive environment with tiled display wall for intuitive remote collaborative work

In remote collaborative work via WAN, sharing and recognizing various high-quality visual contents such as photography, visualization image, and real video streaming is extremely important. Supporting a high-quality display of these contents on a large-scale display system is necessary to support intellectual remote collaborative work. However, these contents are currently magnified in low resolution on a general projector used as large-sized display equipment, and these equipments are difficult to display the contents with sufficient quality. In this paper, we have focused on the tiled display wall technology which configure a wide-area screen with two or more LCD and tried to display realistic high-resolution visual contents to solve these issues. We have constructed a tele-immersive environment with a tiled display wall, and have studied the availability for intuitive remote collaborative work by implementing various collaborative applications for the effective display of high-resolution contents as well as developing interaction techniques for enormous visual contents in this environment. As a result, we have showed that the practical use of a tiled display wall is useful in the construction of intellectual remote collaborative environment.     

A scalable distributed paradigm for multi-user interaction with tiled rear projection display walls

We present the first distributed paradigm for multiple users to interact simultaneously with large tiled rear projection display walls. Unlike earlier works, our paradigm allows easy scalability across different applications, interaction modalities, displays and users. The novelty of the design lies in its distributed nature allowing well-compartmented, application independent, and application specific modules. This enables adapting to different 2D applications and interaction modalities easily by changing a few application specific modules. We demonstrate four challenging 2D applications on a nine projector display to demonstrate the application scalability of our method: map visualization, virtual graffiti, virtual bulletin board and an emergency management system. We demonstrate the scalability of our method to multiple interaction modalities by showing both gesture-based and laser-based user interfaces. Finally, we improve earlier distributed methods to register multiple projectors. Previous works need multiple patterns to identify the neighbors, the configuration of the display and the registration across multiple projectors in logarithmic time with respect to the number of projectors in the display. We propose a new approach that achieves this using a single pattern based on specially augmented QR codes in constant time. Further, previous distributed registration algorithms are prone to large misregistrations. We propose a novel radially cascading geometric registration technique that yields significantly better accuracy. Thus, our improvements allow a significantly more efficient and accurate technique for distributed self-registration of multi-projector display walls.     

High-performance optimizations on tiled many-core embedded systems: a matrix multiplication case study

Technological advancements in the silicon industry, as predicted by Moore’s law, have resulted in an increasing number of processor cores on a single chip, giving rise to multicore, and subsequently many-core architectures. This work focuses on identifying key architecture and software optimizations to attain high performance from tiled many-core architectures (TMAs)—an architectural innovation in the multicore technology. Although embedded systems design is traditionally power-centric, there has been a recent shift toward high-performance embedded computing due to the proliferation of compute-intensive embedded applications. The TMAs are suitable for these embedded applications due to low-power design features in many of these TMAs. We discuss the performance optimizations on a single tile (processor core) as well as parallel performance optimizations, such as application decomposition, cache locality, tile locality, memory balancing, and horizontal communication for TMAs. We elaborate compiler-based optimizations that are applicable to TMAs, such as function inlining, loop unrolling, and feedback-based optimizations. We present a case study with optimized dense matrix multiplication algorithms for Tilera’s TILEPro64 to experimentally demonstrate the performance and performance per watt optimizations on TMAs. Our results quantify the effectiveness of algorithmic choices, cache blocking, compiler optimizations, and horizontal communication in attaining high performance and performance per watt on TMAs.     

Evaluation study on realistic sensation in tele-communication environment with ultra-resolution video by multiple cameras on tiled display wall

To enhance a high-realistic sensation for participants in tele-communication over the Internet, space sharing by displaying super-quality video is effective. However, in commonly used tele-communication systems, participants have found it difficult to feel an ordinary presence and realistic sensation in real environments, and an effective solution has still not been proposed. We have constructed a tele-communication environment to display an ultra-resolution video which realizes a display resolution over 4K on a tiled display wall by multi-transmitting each video captured by multiple cameras. Nonetheless, the need for objective evaluation and analysis on the realistic sensation that participants feel in tele-communication has been increasing. However, there are only a few case studies on detailed analysis and evaluation of the factors required for realistic sensation in tele-communication. In this paper, we have conducted an experiment to evaluate and analyze the effectiveness of realistic sensation and its effect on participants in this tele-communication environment. From experimental results, we have shown that this tele-communication environment has a strong tendency to provide higher realistic sensation for estimators.     

Software for graphic display systems

In this paper some aspects of graphic display systems are discussed. The design of a display subroutine library is described, with an example, and graphic dialogue software is considered primarily from the point of view of the programmer who uses a high-level language.     

远程图形终端系统综述

随着计算机和网络的迅速发展,远程图形终端系统作为一种方便的远程控制平台,在远程管理、远程协助、远程医疗和远程教育等应用中发挥着越来越重要的作用,其性能也直接影响到这些应用系统的性能。该文讨论了设计改进远程图形终端系统所要考虑和解决的问题,接着从远程显示方式、更新机制、压缩机制、缓存机制和评价方法等方面,较全面地介绍和分析了当前主流远程图形终端系统的技术发展现状,并在此基础上对远程图形终端系统的发展方向进行了展望．     

Using a projection-based approach to mine frequent inter-transaction patterns

In this paper, we propose an algorithm called PITP-Miner that utilizes a projection based approach to mine frequent inter-transaction patterns efficiently. The algorithm only searches for local frequent items in a projected database that stores potential local inter-transaction items and partitions the database into a set of smaller databases recursively. In addition, two pruning strategies are designed to further condense the partitioned databases and thus accelerate the algorithm. Our experiment results demonstrate that the proposed PITP-Miner algorithm outperforms the ITP-Miner and FITI algorithms in most cases.     

A systems theoretical approach to online knowledge building

This article describes the phenomenon of knowledge building in online environments. Knowledge building is a process within a community, which leads to the development of knowledge. In order to analyze this process, we will look into the ways in which individuals interact with the collective as a whole. For this purpose, the psychic and social systems, which are involved here are regarded as meaning-based systems in the sense of Luhmann’s systems theory—open to the environment, but operatively closed. The respective modes of operation of psychic and social systems will be examined, and “structural coupling” between these systems described. Another characteristic of knowledge-building communities is self-organization, which is described here in the sense of autopoiesis. A pivotal task, which knowledge-building communities have to tackle, is to handle complexity and reach common understanding. These aspects will also be described using conceptualizations of Luhmann’s systems theory, illustrated by many examples.     

Introduction to object-oriented systems engineering. 2

Based on a set of views for the system, use cases help define the behavior of a system, from its top level to its terminal components. They are used in object-oriented systems engineering (OOSE) to provide a framework that ensures consistent systems development.     

Introduction to object-oriented systems engineering.1

Within software development, object-oriented (OO) analysis provides an incremental and iterative approach to guide the requirements definition, design, and development of software-intensive systems. OO analysis uses the Unified Modeling Language (UML) to capture and represent these requirements. UML permits specification of the product independent of programming language or development process. This independent product representation has raised interest in the systems engineering community: OO methods might be a mechanism to unite product development disciplines and remove the gap between the specified and as-built products. The paper discusses the object oriented systems engineering process.