Walkthrough System Research Articles

Research and implementation of digital 3D panoramic visual communication technology based on virtual reality

SummaryBased on the digital three‐dimensional (3D) panoramic technology of sequence pictures, the static pictures are stitched together to form a 360‐degree panoramic image, which can truly reproduce the real scene. Panoramic images are widely used, making this technology a hot spot in the research of virtual reality technology. This paper completes the research content of the application value of the digital 3D panorama, the key technology of digital 3D panorama technology, and the design and display of 3D panorama campus through practical application. This article comprehensively introduces the hardware equipment of panoramic technology and the technical requirements of panoramic image acquisition in the field of practical application, and combines the actual cases to systematically produce panoramic image stitching, panoramic image generation, and virtual roaming campus construction; 3D panoramic technology is a brand‐new form of viewing images, discussing and studying the artistic expression of 3D panoramic images, and researching its innovative application in visual communication art. In this paper, the chromaticity calibration of digital camera and projection equipment is used to eliminate the coupling difference between the two; then estimate the spectral reflectance of the three‐color channel of the object and separate the specular reflection component and the diffuse reflection component, at the same time correct the color and specular reflectance of the object itself, and analyze the influence of reflection on the color of the projection light source. This article describes the design ideas and key technologies of the school's 3D panoramic walkthrough system, describes in detail the process of the system from demand analysis to system design and finally realization, and focuses on the production method of panoramic images and the main functional modules in the walkthrough system. At the end, the system was tested, and the existing problems were analyzed, and solutions were provided. Research shows that when the roaming system has 3,000 concurrent users, it can read a single scene for about 3 s on average.

Review of Active Millimeter Wave Imaging Techniques for Personnel Security Screening

This paper reviews recent progress of active millimeter wave (mmW) imaging techniques for personnel security screening. With the ability to penetrate clothing and the promised millimeter scale spatial resolution, mmW imaging has been widely pursued for personnel surveillance without the usual concern for radiation safety. A brief development history of mmW imaging is introduced. An overview of imaging research and developmental achievements, along with antenna considerations based on quasi-optical geometry, phased reflector array, monostatic array, and multistatic array, is provided. Design considerations related to practical applications, including system calibrations, walk-through system (WTS), portable system, and compressive sensing (CS), are also discussed.

Force Rendering and its Evaluation of a Friction-Based Walking Sensation Display for a Seated User.

Most existing locomotion devices that represent the sensation of walking target a user who is actually performing a walking motion. Here, we attempted to represent the walking sensation, especially a kinesthetic sensation and advancing feeling (the sense of moving forward) while the user remains seated. To represent the walking sensation using a relatively simple device, we focused on the force rendering and its evaluation of the longitudinal friction force applied on the sole during walking. Based on the measurement of the friction force applied on the sole during actual walking, we developed a novel friction force display that can present the friction force without the influence of body weight. Using performance evaluation testing, we found that the proposed method can stably and rapidly display friction force. Also, we developed a virtual reality (VR) walk-through system that is able to present the friction force through the proposed device according to the avatar's walking motion in a virtual world. By evaluating the realism, we found that the proposed device can represent a more realistic advancing feeling than vibration feedback.

景観ウォークスルー型VRにおける立体視の生体に与える影響に関する一考察(景観,映像表現フォーラム)

景観ウォークスルー型VRにおける立体視の生体に与える影響に関する一考察(景観,映像表現フォーラム)

Optimally Redundant, Seek-Time Minimizing Data Layout for Interactive Rendering

Performance of interactive graphics walkthrough systems depends on the time taken to fetch the required data from the secondary storage to main memory. It has been earlier established that a large fraction of this fetch time is spent on seeking the data on the hard disk. In order to reduce this seek time, redundant data storage has been proposed in the literature, but the redundancy factors of those layouts are prohibitively high. In this paper, we develop a cost model for the seek time of a layout. Based on this cost model, we propose an elegant algorithm that computes a redundant data layout with the redundancy factor that is within the user-specified bounds, while maximizing the performance of the system. By using a set of training access requirements and a set of validation access requirements, our proposed method is able to automatically maximize system performance with an optimal redundancy factor. Experimental results show that the interactive rendering speed of the walkthrough system was improved by a factor of 2---4 by using our data layout method when compared to existing methods with or without redundancy.

船舶機関士の安全教育における機関室ウォークスルーシステムの応用

船舶機関士の安全教育における機関室ウォークスルーシステムの応用

Efficient framework for mobile walkthrough application

The past few years have witnessed a dramatic growth in the number and variety of graphics intensive mobile applications, which allow users to interact and navigate through large scenes such as historical sites, museums and virtual cities. These applications support many clients and impose a heavy requirement on network resources and computational resources. One key issue in the design of cost efficient mobile walkthrough applications is the data transmission between servers and mobile client devices. In this paper, we propose an effective progressive mesh transmission framework that stores and divide scene objects into different resolutions. In this approach, each mobile device progressively receives and processes only the object’s details matching its display resolution which improves the overall system’s response time and the user’s perception. A fine grained cache mechanism is used to keep the most frequently requested objects’ details in the device memory and consequently reduce the network traffic. Experiments, in simulated and real world environment, are used to illustrate the effectiveness of the proposed framework under various settings of the virtual scene and mobile device configuration. Experimental results show that the proposed framework can improve the walkthrough system performance in mobile devices, with a relatively small overhead.

Application of Scene Simulation Technology to the Walkthrough System

In this paper, the application of Scene Simulation technology to walkthrough is introduced in detail, and two key links of system implement with the scene simulation technology are analyzed, which are the construction of three-dimensional model and the implement of the walkthrough drive engine. MultiGen and OpenGVS are selected to be the walkthrough system development platform. The whole system realization from the construction of three-dimensional model to implement of the walkthrough drive engine is discussed particularly.

Spectrum-based synthesis of vibrotactile stimuli: active footstep display for crinkle of fragile structures

When a human crinkles or scrunches a fragile object, for which the yield force is very small that it is hardly perceived, they identify the material of the object based on tactile stimuli delivered to the skin. In addition, humans are able to recognize materials even when they are crinkled at different speeds. In order to realize these human recognition features of the crinkle of a fragile object, we develop a vibrotactile synthesis method. This method synthesizes the vibrotactile acceleration stimuli in response to a crinkle speed based on the preliminarily measured acceleration spectra. Using this method, we develop an active footstep display that presents a virtual crinkle of fragile structures made of different materials to its users. Experimental participants could identify three of the four types of virtual structure materials at rates significantly higher than the chance level. The four materials were copy and typing paper, aluminum foil, and polypropylene film. Furthermore, the trends of answer ratios exhibit good correspondence with those for the real cylindrical fragile objects. We conclude that the developed method is valid for the virtual crinkle of fragile structures and will enhance the validity of virtual reality systems, such as a virtual walkthrough system.

Utilizing Traveral Sequence Order for Storage Layout in Walkthrough

3D walkthrough (henceforth referred as WT) becomes popular and apparent when the volume of query processing in some 3D scenery (e.g., the walkthrough system and the 3D museum navigation systems) is considered. In this scenario, different people with similar behaviours induce completely different space-time traversal patterns in a recoded traversal sequence. This is because they navigate different paths, and their surrounding backgrounds are different. What are common across such sequences of the same behaviours are the underlying induced walkthrough fields. We want to make use of regions of common sequential traversal patterns for acceleration and compaction purposes. In this paper we propose a new Sequence-based Pattern Similarity (SPS) approach based on a behavioural walkthrough system that exploits sequence-based semantic-oriented clustering techniques, such as association, intra-relationships, and inter-relationships, to explore additional links throughout the behavioural walkthrough system. The experimentation shows that in such cases the use of so-called I/O-efficient algorithms that minimize the number of disk accesses can lead to tremendous runtime improvements.

Design and Implementation of Campus 3D Virtual Walkthrough System - Take Hunan Science and Technology University as an Example

Along with the rapid development of computer and network technology, the current of digitization has become inevitable trend of global economic development, and digital city has gradually aroused people's attention in recent years. In the application of urban simulation, people can have an immersion omnibearing walkthrough with the method of dynamic interaction in a virtual 3D environment. Without ever leaving home, you can appreciate the scenery of a strange city. This paper has researched key technology of scene simulation on visual reality, and implementd the scene simulation system based on visual environment of Hunan Science and Technology University. With the practice and test, the constructed campus simulation system in the paper has operated smoothly, and users can achieve the visual walkthrough on campus.

The Research of City Walkthrough System Based on Voice Navigation

Digital walkthrough technology has been widely applied in the city planning in resent years, while the existing techniques of digital walkthrough has the disadvantage of unitary operation and speech interaction deficiency. Based on the above analysis, aimed to overcome the conventional techniques disadvantage, the paper introduces the novel theory of virtual technology and voice control technology, researching the application of voice navigation in digital walkthrough designed and studied by combining the actual need of the city planning.

Development of an Evacuation Simulator using a Walkthrough System and Research on Evacuation Behavior in the Case of Fire

This research focuses on back-homing instinct, visible escape direction choices and tracking among escape direction choices in case of emergency, and to show the environment where such behavioral characteristics appear in a quantitative manner. An evacuation simulator using a walkthrough system was conducted. The results showed that 50% of evacuees who were not familiar with an architectural structure chose back-homing and the others searched for a new evacuation direction when they noticed a fire. For subjects who chose back-homing, 46.6% of evacuees still chose back-homing after observing the surrounding area and obtaining environmental information on both signs and other evacuees, while 53.4% chose to search for a new escape direction by following signs or other evacuees. It was found that the level concerning memory of a route to an evacuation point and the distance to an evacuation point also affects an escape choice. Also, the ratio of choice of visible escape routes differs according to the case. As a result of the research, it is possible to use this information to design an architectural structure and equipment in a building to minimize fire damage, by establishing evacuation simulation software.

Progressive 3D scenes replacement mechanism for P2P overlay

Recently, walkthrough system of large-scale virtual environments has been a new topic of WebGIS. In order to relieve the contradiction between limit storage of user terminal and massive 3D scenes via Internet, the authors proposed a new Progressive Scenes Replacement Mechanism ( PSRM) which suited the Peer-to-Peer ( P2P) overlay. New concepts of "reuse degree", "visual preservation", and "preservation for Area of Interest ( AOI) neighbors" were introduced respectively. Thus, the old scenes which needed to be replaced could be identified, and these scenes were replaced from high resolution to low resolution progressively. The simulation results show the PSRM improves more in the downloading fill ratio, downloading fill ratio of base mesh compared with the current system, and the workload of server is reduced greatly by using PSRM in the walkthrough.

バーチャルリアリティ技術 双曲面ハーフミラーを用いた超広視野頭部搭載型プロジェクタの設計と実装

In a virtual reality (VR) environment, a wide field-of-view (FOV) image contributes to improve the immersive experience and situation awareness. The typical FOV of a head mounted display (HMD) is around 20 to 40 degrees, and widening this has been a technological challenge for decades. We designed a new HMD that has a hyperbolic half-silvered mirror. This HMD can resolve the technological challenges and provide a wide FOV, large observational pupil, and optical see-through display. We made a prototype HMD and a VR walkthrough system that displays a pair of stereo images with a FOV of over 120 degrees. This paper reports our HMD ' s basic concept and the implementation of the prototype.

Walk-through weighing of pigs using machine vision and an artificial neural network

Machine vision-based weighing of pigs is a non-intrusive, fast and relatively accurate approach that could reduce stress on both the animal and the stockman during the weighing process. An image-based walk-through system was developed in this study for pig liveweight approximation without having to restrain the pig to a certain area for stationary imaging. A protocol was developed to automatically screen and select the images captured for image processing. The artificial neural network technique was used in this study to correlate a multitude of physical features extracted from the walk-through images to pig liveweight in an attempt to improve the accuracy of liveweight approximation. The results showed that the average relative error of the walk-through weighing system was around 3%. The walk-through system has made it even easier for stockmen to obtain the liveweight of pigs using a machine vision-based weighing system.

Real-Time Rendering Depth Images on GPU by Forward Warping

This paper presents a new pipeline for rendering depth images entirely on GPU (graphics processing unit). The implementation exploits inherent parallelism of GPU to speed up the rendering of depth images. By the scheme, a novel forward 3D warping method is proposed for vertex shader to obtain high rendering performance. Furthermore, the hardware pipeline’s rasterization function is utilized to conduct the image re-sampling efficiently to generate holes free rendering results. Per pixel lighting effect is implemented in pixel shader to get high image quality. The rendering shows rapid performance at full screen resolution, with correct self-occlusions and accurate silhouettes. Moreover, a real-time walkthrough system is implemented for the objects based on cylindrical depth image rendered by view-dependent dynamic LOD (level of detail) representation at runtime.

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442 大規模非定常有限要素解析結果のウォークスルー可視化(CGと計算力学,OS02 CGと計算力学)

Nowadays the application area of numerical simulation is growing rapidly. Many researchers challenge complicated and large-scale simulation, for example seismic response simulation. The utilization of ADVENTURE system on the Earth Simulator enables such a time dependent simulation of a large-scale model. As this technology advances, post processing requires further advancement. We should think about how to deal with a huge amount of data. In particular, visualization demands interaction with users' needs. One of the solutions of those demands is to develop a Walkthrough Visualization System in a precise simulation world. In this research, we propose a Walkthrough System for structural simulations of a large-scale and complex model.

An Efficient Clustering Algorithm for Patterns Placement in Walkthrough System

Mining of sequential patterns in walkthrough systems is an interesting data mining problem. It can be envisioned as a tool for forecasting and prediction of the future behavior of user’s traversal patterns. In the past, how to display the object faster in the next time were their concerns. They seldom consider the problem of access times of objects in the storage systems. In this paper, we will consider this problem and solve this by clustering. Clustering methodology is particularly appropriate for the exploration of interrelationships among objects to reduce the access times of objects. We record the user’s path as log-data and store it in database. After a certain period of time, we will process the log-data database for user traversal paths and find out their characteristics, which will be utilized to determine the optimal physical organization of those VRML objects on disks. Meanwhile, we also introduce the relationships among transactions, views and objects. According to these relationships, we suggest the clustering criteria--inter-pattern similarity, which utilize these characteristics to distribute the objects into the appropriate clusters. As a result, the large-scale VRML models could be accessed more efficiently, allowing for a real-time walk-through in the scene.