bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Development of an Augmented Reality Robotic System for Large Tumor Ablation
Authors: Yang Liangjing , Chui Chee-Kong , Chang Stephen
Published: October 2019

An augmented reality based robotic system is proposed for treatment of large liver tumor using multiple overlapping ablations technique. Radiofrequency ablation is a non-resection interventional procedure that minimizes invasiveness and reduces trauma. A single ablation is however limited by the ablation volume coverage. In treatment of tumor with diameter that could be 150mm or more, a single needle insertion will not create sufficient ablation coverage to destroy the entire tumor. As such, multiple insertions are required. The precision and consistency associated with robot assisted surgery coupled with direct augmented reality projection system can better facilitate such treatment. The projection system is equipped with manipulator mechanism and robotic needle insertion arm for multiple insertions and needle deployment. The prototype augmented reality surgical system was evaluated on its abilities in ablating large tumor. Virtual models of the rectangular robot for projector manipulation and robotic needle insertion device were also used to assess the effectiveness of the proposed AR design.
A Framework for GPU-accelerated Virtual Cardiac Intervention
Authors: Yu Rongdong , Chiang Patricia , Chen Wenyu , Zheng Jianmin , Cai Yiyu , Ye Xiuzi , Zhang Sanyuan , Zhang Yin , Mak Koon-Hou
Published: October 2019

Cardiovascular diseases is a major cause of deaths in many developed countries. To treat cardiovascular diseases, minimally invasive cardiac intervention is widely used as an effective yet complicated solution. Training of cardiac intervention thus plays a crucial role. This paper addresses the use of Virtual Reality (VR) technology for the simulated training of cardiac intervention. In particular, the paper describes the architecture of a simulation system for virtual cardiac intervention. The framework proposed consists of hardware component, software component and methodology component. As an enabling technology, Graphics Processing Unit (GPU) is applied in this work to enhance cardiac modeling, cardiac visualization, and cardiac interaction with the VR simulation environment
On the Determinants of Size-Constancy in a Virtual Environment
Authors: Luo Xun , Kenyon Robert V. , Kamper Derek G. , Sandin Daniel J/ , DeFanti Thomas A.
Published: October 2019

An important aspect of a subject�s perception of virtual objects in a virtual environment is whether the size of the object is perceived as it would be in the physical world, which is named size-constancy. The ability of subjects to appreciate size-constancy in an immersive virtual environment was studied while scene complexity, stereovision and motion parallax visual factors were manipulated resulting in twelve different viewing conditions. Under each visual condition, 18 subjects made size judgments of a virtual object displayed at five different distances from them. Responses from the majority of our population demonstrated that scene complexity and stereovision have a significant impact on subjects' ability to appreciate size-constancy. In contrast, motion parallax produced by moving the virtual environment or by the movements of the observer alone proved not to be a significant factor in determining size-constancy performance. Consequently, size-constancy is best obtained when scene complexity and stereovision are components of the viewing conditions.
A Survey of Technologies for Building Collaborative Virtual Environments
Authors: Wright Timothy E. , Madey Greg
Published: October 2019

What viable technologies exist to enable the development of so-called desktop virtual reality (desktop-VR) applications? Specifically, which of these are active and capable of helping us to engineer a collaborative, virtual environment (CVE)? A review of the literature and numerous project websites indicates an array of both overlapping and disparate approaches to this problem. In this paper, we review and perform a risk assessment of 16 prominent desktop-VR technologies (some building-blocks, some entire platforms) in an effort to determine the most efficacious tool or tools for constructing a CVE
Estimation of Distances in Virtual Environments Using Size Constancy
Authors: Murgia Alessio , Sharkey Paul M.
Published: October 2019

It is reported in the literature that distances from the observer are underestimated more in virtual environments (VEs) than in physical world conditions. On the other hand estimation of size in VEs is quite accurate and follows a size-constancy law when rich cues are present. This study investigates how estimation of distance in a CAVETM environment is affected by poor and rich cue conditions, subject experience, and environmental learning when the position of the objects is estimated using an experimental paradigm that exploits size constancy. A group of 18 healthy participants was asked to move a virtual sphere controlled using the wand joystick to the position where they thought a previously-displayed virtual cube (stimulus) had appeared. Real-size physical models of the virtual objects were also presented to the participants as a reference of real physical distance during the trials. An accurate estimation of distance implied that the participants assessed the relative size of sphere and cube correctly. The cube appeared at depths between 0.6 m and 3 m, measured along the depth direction of the CAVE. The task was carried out in two environments: a poor cue one with limited background cues, and a rich cue one with textured background surfaces. It was found that distances were underestimated in both poor and rich cue conditions, with greater underestimation in the poor cue environment. The analysis also indicated that factors such as subject experience and environmental learning were not influential. However, least square fitting of Stevens' power law indicated a high degree of accuracy during the estimation of object locations. This accuracy was higher than in other studies which were not based on a size-estimation paradigm. Thus as indirect result, this study appears to show that accuracy when estimating egocentric distances may be increased using an experimental method that provides information on the relative size of the objects used.
Dynamic Transparency for 3D Visualization: Design and Evaluation
Authors: Elmqvist Niklas , Assarsson Ulf , Tsigas Philippas
Published: October 2019

Recent developments in occlusion management for 3D environments often involve the use of dynamic transparency, or "virtual X-ray vision", to promote target discovery and access in complex 3D worlds. However, there are many different approaches to achieving this effect and their actual utility for the user has yet to be evaluated. Furthermore, the introduction of semitransparent surfaces adds additional visual complexity that may actually have a negative impact on task performance. In this paper, we report on an empirical user study investigating these human aspects of dynamic transparency. Our implementation of the technique is an image-space algorithm built using modern programmable shaders to achieve real-time performance and visually pleasing results. Results from the user study indicate that dynamic transparency provides superior performance for perceptual tasks in terms of both efficiency and correctness. Subjective ratings are also firmly in favor of the method.
Large Area Robust Hybrid Tracking with Life-size Avatar in Mixed Reality Environment for Cultural and Historical Installation
Authors: Pensyl William Russell , Qui Tran C. T. , Hsin Pei Fang , Lee Shang Ping , Jernigan Daniel K.
Published: October 2019

We have developed a system which enables us to track participant-observers accurately in a large area for the purpose of immersing them in a mixed reality environment. This system is robust even under uncompromising lighting conditions. Accurate tracking of the observer�s spatial and orientation point of view is achieved by using hybrid inertial sensors and computer vision techniques. We demonstrate our results by presenting a life-size, animated human avatar sitting in a real chair, in a stable and low-jitter manner. The system installation allows the observers to freely walk around and navigate themselves in the environment even while still being able to see the avatar from various angles. The project installation provides an exciting way for cultural and historical narratives to be presented vividly in the real present world.
Application of Virtual Reality and Plant Modeling for Participation in Urban Planning and Design
Authors: Lim Enmi , Umeki Kiyoshi , Honjo Tsuyoshi
Published: October 2019

In landscape planning, visualization of landscape is a powerful tool for public understanding and for selection of alternative plans. In recent years, three dimensional (3D) computer graphics (CG) were used as visualization tools of environment because it has the ability to accurately simulate the changes caused by a proposed plan. In particular, virtual reality (VR), which enables to walk through in a modeled park or in a visualized forest, was considered as the advanced technique of landscape visualization. In this study, we developed a landscape visualization system with graphic user interface, which we named VR-Terrain (GUI version), to generate the virtual reality image easily by using VRML (Virtual Reality Modeling Language) and plant modeling techniques. In order to test the feasibility of the landscape visualization system, we applied the system to Ichinoe Urban Design Plan. Ichinoe is located at Edogawa Ward, Tokyo. There is a Sakaikawa Shinsui Park with water space surrounded by large amount of green. In the case study, we simulated the landscape of Sakaikawa Shinsui Park with about 200 plants and 300 buildings. We used the images simulated by VR-Terrain to explain the concept (such as building height limit) to the residents in the public meetings. It took about 30 hours to make the 3D model of the town. After ten minutes of training, anybody can walk through in the simulated town freely. The results showed that the VR image by the system helped the public understanding of the concept of the urban plan.
Feature-Based Simplification of Process Plant Models over Network
Authors: Su Zhiyong , Xia Ming , Li Weiqing , He Tao , Tang Weiqing
Published: October 2019

Visualization of 3D process plant models is an essential feature to support design review in distributed design environment. The preprocessing time, frame rate and visual fidelity play the same import role in improving the effectiveness and efficiency of the entire design review process. General model simplification algorithms, such as levels of detail (LODs) and hierarchical levels of detail (HLODs), always need unbearable time for preprocessing large-scale models and may distort design feature and make them unrecognizable to the reviewer. To efficiently transmit models, various compression technologies can be applied to shrink the data size. However, transmitting large-scale models over network is still a bottleneck of rendering performance. In this paper, we presented a new, faster feature-based model simplification algorithm to simplify process plant models over network. We first get the model's geometric parameters and topology information from the server before visualization. Then we compute LODs and HLODs according to the model�s geometric parameters and composing feature on the client. No triangles are transmitted during visualization. We demonstrate its performance on complex process plant models composed of tens of millions of triangles. Results show that our approach is able to shorten the preprocessing time greatly. And it can achieve considerable speedups in frame rate with little loss in image quality.
InterANTARCTICA: Tangible User Interface for Museum Based Interaction
Authors: De Bérigny Wall Caitilin , Wang Xiangyu
Published: October 2019

This paper presents the design and concept for an interactive museum installation, InterANTARCTICA. The museum installation is based on a gesture-driven spatially surrounded tangible user interface (TUI) platform. The TUI allows a technological exploration of environmental climate change research by developing the status of interaction in museum installation art. The aim of the museum installation is to produce a cross-media platform suited to TUI and gestural interactions. We argue that our museum installation InterANTARCTICA pursues climate change in an interactive context, thus reinventing museum installation art in an experiential multi-modal context (sight, sound, touch).
Korean Traditional Space Creator for Digital Contents
Authors: Kang Seungmook , Kim Hadong
Published: October 2019

Since 2009, the Korean government began to invest heavily in the field of digital contents based on Korean cultural heritage like Korean dramas, films, animation, and virtual reality application. The investment was caused by Korean Wave, which is the surge of popularity of South Korean culture around the world since the 21st century [1], also called Hallyu in Korean. However the Korean historical dramas and films have misarranged the components of Korean traditional houses and ornaments chronologically and spatially. The typical problem is coming from the lack of reference to who builds the sets. The one of the solutions is Korean Space Creator that has real time renderer to show the created space instantly and the database of traditional Korean house components, then it is easy for digital contents producers to use. At present the application has the specific regional materials of Chosun Dynasty (1392-1910) in database; it will extend to more region and dynasties.
Morphology independent motion retrieval and control
Authors: Pronost Nicolas , Multon Franck , Li Qilei , Geng Weidong , Kulpa Richard , Dumont Georges
Published: October 2019

This paper addresses the problem of selecting and adapting a motion in order to make a virtual human interact with a user in real-time. We describe a method that is able to retrieve the most appropriate motion in interactive environments where both the constraints and the character's morphology are not known in advance. The method described here is based on a morphology-independent representation of motion to perform fast motion retargetting and retrieval. Because the size of the database is not infinite, even the best candidate motion may not satisfy precisely all the imposed constraints. As a second step of the algorithm, the selected motion is locally adapted in order to accurately satisfy these constraints. This adaptation allows dealing with a large set of possible movements even if no candidate in the database exactly fits the constraints.
Dynamic models of team rowing for a virtual environment rowing training system
Authors: Filippeschi Alessandro , Ruffaldi Emanuele , Frisoli Antonio , Avizzano Carlo Alberto , Varlet Manuel , Marin Ludovic , Lagarde Julien , Bardy Benoit , Bergamasco Massimo
Published: October 2019

In this paper we report on the strategies adopted to model team rowing behavior for an in-door rowing training system. This system allows athletes to train at in-door location while preserving the main features of out-door rowing. This paper focuses on the dynamic models employed to simulate out-door rowing, as well as on the modeling of team behavior, in order to set up visual feedback for team rowing training. These models are employed for controlling the output in the virtual environment, in particular for training the inter-rower synchronization in a team.
View Synthesis for Realistic Virtual Walk Through Based on Omni-directional Images
Authors: Chen Wang , Xu Wei , Xiong Zhihui , Zhang Maojun
Published: October 2019

Virtual walk through can be widely applied in many industries such as virtual environment construction, history heritage conservation and scenic site exhibition etc. This paper proposes a more convenient and efficient approach to create realistic virtual walk through from catadioptric omni-directional images via view synthesis technique. Our innovation mainly lies in three aspects: omni-directional image preprocessing, image rectification and novel view interpolation. Acquisition and unwarping of omni-directional image are discussed firstly. Then, for specialty of cylindrical panoramic imaging, epiline-sampling method is adopted for rectification, which samples reference images along epilines as much as possible grounding on epipolar geometry. In this way, it can detract the rectified images from image deformation and resolution degeneration, which usually take place due to perspective transformation when using some other algorithms. As to novel view generation, a corresponding interpolation algorithm is developed. Pixels on novel view are formulated according to the cylindrical panoramic imaging model. Experiments carried out on both synthetic and real scene are given at the end of this paper, with a demonstration of the method's application in realistic virtual walk through.
Fast 3D Shape Recovery from Shadows Projected on Arbitrary Curved Surfaces
Authors: Yamashita Yukihiro , Sakaue Fumihiko , Sato Jun
Published: October 2019

The shadow based 3D surface reconstruction methods usually assume that shadows are projected on planar surfaces. However, shadows are often projected on curved surfaces in the real scene. Recently, the shadow graph has been proposed for representing shadow information efficiently, and for recovering 3D shapes from shadows projected on curved surfaces. Unfortunately, the method requires a large computational cost and is weak to the image intensity noises. In this paper, we introduce 1D shadow graphs which can represent shadow information quite efficiently, and can be used for recovering 3D shapes with much smaller computational costs than before. We also extend our method, so that we can recover 3D shape quite accurately by using shading information as well as shadow information. The proposed method is tested by using the real and synthetic images.
Surface Reconstruction from Multi-View Stereo of Large-Scale Outdoor Scenes
Authors: Salman Nader , Yvinec Mariette
Published: October 2019

This article describes an original method to reconstruct a 3D scene from a sequence of images. Our approach uses both the dense 3D point cloud extracted by multi-view stereovision and the calibrated images. It combines depth-maps construction in the image planes with surface reconstruction through restricted Delaunay triangulation. The method may handle very large scale outdoor scenes. Its accuracy has been tested on numerous outdoor scenes including the dense multi-view benchmark proposed by Strecha et al. Our results show that the proposed method compares favorably with the current state of the art.
Assessment of Stereoscopic Multi-resolution Images for a Virtual Reality System
Authors: Ogawa Masahiko , Shidoji Kazunori , Matsuki Yuji
Published: October 2019

A camera and monitor system that projects actual real-world images has yet to be developed due to the technical limitation that the existing cameras cannot simultaneously acquire high-resolution and wide-angle images. In this research, we try to resolve this issue by superimposing images; a method which is effective because the entire wide-angle image does not necessarily need to be of high resolution because of perceptual characteristics of the human visual system. First, we examined the minimum resolution required for the field of view, which indicated that a triple-resolution image where positions more than 20 and 40 deg from the center of the visual field were decreased to 25% and approximately 11% of the resolution of the gaze point, respectively, was perceived as similar to a completely high-resolution image. Next, we investigated whether the participants could distinguish between the original completely high-resolution image and processed images, which included triple-resolution, dual-resolution, and low-resolution images. Our results suggested that the participants could not differentiate between the triple-resolution image and the original image. Finally, we developed a stereoscopic camera system based on our results
3D Anthropomorphic Avatar Model Based on Multi-layered Representation
Authors: Wang Zheng , Xu Bo
Published: October 2019

Avatars are virtual characters making the communication between user and machine more natural and interactive. The main advantage of using avatars within interfaces is to allow user to interact intuitively with the system by giving him the illusion of communicating with a real human. This illusion is obtained by mimicking human communication, i.e. giving avatar the ability of expressing emotions through facial and body language. We proposed the method based on multi-layered representation for a kind of 3D anthropomorphic avatar, and validated it as an information presenter. The way of controlling the avatar's emotion is to use parameterized facial muscle model and skeleton skinning, scheduled with multi-thread. Then a series of naturalistic avatar animation produced.
Avatar-based Intelligent Navigation for Online Shanghai Expo
Authors: Zhang Mingmin , Xiang Nan , Wang Kangkan , Pan Zhigeng , Yuan Haibo , Liu Houquan
Published: October 2019

Shanghai Expo 2010 is an international event which will demonstrate the scientific, economic and cultural advance of the exhibiting countries. The local government launches a project named on-line Shanghai Expo in order to make the event accessible to people through Internet. Virtual reality technologies, especial intelligent virtual environment (IVE), are exploited to support the Expo. IVE, based on semantic, is the integration of Virtual Environment and Artificial Intelligence. It can improve the interaction between avatar and the virtual world by giving the objects in the environment semantic information. In this paper we employ intelligent virtual environment to build a virtual environment of realistic behavior and intelligent navigation.
Automatic 3D Reconstruction from a Single Catadioptric Omnidirectional Image
Authors: Gao Hui , Xu Wei , Zhang Maojun
Published: October 2019

In this paper we present a method for 3D urban reconstruction from a single catadioptric omnidirectional image. Firstly, we classify the catadioptric omnidirectional image to horizontal ground, vertical building surface and vertical background surface through the registration between catadioptric omnidirectional image and remote sensing image. According to the classification results, we recover the geometry based on the catadioptric projection model. The experiment shows that our method is feasible and realizes a precise 3D reconstruction for the city scenes.
A Pen-Based Interactive Projection System Based on the Infrared Scanning Projector
Authors: Guo Qianrui , Wang Yongtian , Liu Yue , Han Dong
Published: October 2019

Nowadays, how to make a human-computer interaction system which can take into account large-area display, high precision tracking and multi-user operation at the same time is a hot research topic. This paper presents a novel low cost pen-based projective interaction system that can write or draw like writing brush. The system is composed of infrared scanning projector, digital pen, projector, screen, wireless receiver module and computer. The infrared scanning projector is designed to achieve fast projection, which is to track the pen's two dimensional location accurately along with the digital pen. The system has the advantage of multi-user supported, high tracking precision, and has the function of identity recognition and writing calligraphy.
Fractal Cityscape
Authors: Li Baihua , Miller James
Published: October 2019

There is an increasing demand for the simulation of large-scale "free-flow" urban environments in games or other virtual reality worlds. Currently most 3D cityscapes are generated by time consuming manually pre-scripted "room-to-room" approaches. Although the effectiveness of fractal modelling of rural landscape or architecture has been studied extensively, there is a relative dearth of research on fractal modelling of cityscapes. Inspired by modern fractal city theory, we intend to develop an automatic fractal-based method to address this problem. In particular, we will investigate how fractal theory can be used to mathematically simulate the multi-level hierarchical urban structure corresponding to various land use property probabilities of city regions. Tentative findings and results are presented in this paper
Constructing Subdivision Connectivity Mesh via PDE Parameterization
Authors: Pang Mingyong , Sourin Alexei , Pan Zhigeng
Published: October 2019

In this paper we present a novel algorithm for constructing subdivision connectivity mesh from dense original mesh. Our algorithm begins from a coarse base mesh generated from the original mesh and then the original mesh is divided into a set of patches guided by the base mesh. The patches are subsequently parameterized onto a planar domain by the mean value coordinates method. For each mesh patch, four boundary condition curves are calculated via the parameterization for local PDE patch construction. Considering the boundary curves as shape control boundary curve conditions, a PDE patch can be built and its coefficients are evaluated from the boundary curves. The PDE patch gives an explicit parametric representation of the mesh patch. Finally, all the PDE patches are remeshed via the planar parametric domains and a new resampled mesh with subdivision connectivity can be obtained with an arbitrary resolution
Avatar Locomotion in Crowd Simulation
Authors: Pelechano Nuria , Spanlang Bernhard , Beacco Alejandro
Published: October 2019

This paper presents an Animation Planning Mediator (APM) designed to synthesize animations efficiently for virtual characters in real time crowd simulation. From a set of animation clips, the APM selects the most appropriate and modifies the skeletal configuration of each character to satisfy desired constraints (e.g. eliminating foot-sliding or restricting upper body torsion), while still providing natural looking animations. We use a hardware accelerated character animation library to blend animations increasing the number of possible locomotion types. The APM allows the crowd simulation module to maintain control of path planning, collision avoidance and response. A key advantage of our approach is that the APM can be integrated with any crowd simulator working in continuous space. We show visual results achieved in real time for several hundreds of agents, as well as the quantitative ac-curacy.
3D Surface Reconstruction of Stone Tools by Using Four-Directional Measurement Machine
Authors: Altantsetseg Enkhbayar , Muraki Yuta , Chiba Fumito , Konno Kouichi
Published: October 2019

In this paper, we present a whole procedure for constructing 3D models of stone tools including scanning, data acquisition and surface reconstruction with hole-filling. The process of scanning hundreds or thousands of small objects is time consuming. Our original 3D laser scanner optimizes the scanning process and reduces time significantly by four directional scanning of many small objects simultaneously. To reconstruct surface of stone tools, the scanned point clouds are processed with a new triangulation method that preserves the properties of sharp edges. Our approach is based on a projection based method in which points are distinguished into neighboring layers with a point cloud slicing method to be individually reconstructed. In addition, we introduce a simple hole-filling algorithm for mesh completion of models. The main advantages of our approach are speed and efficiency for reconstruction of many small objects.
Landscape Simulation and Visualization on Google Earth
Authors: Honjo Tsuyoshi , Umeki Kiyoshi , Wang Darhsiung , Yang Pinan , Hsieh Hanching
Published: October 2019

In this study, we made a landscape visualization system that enables virtual experience in a planned landscape including vegetation on Google Earth. The applicability of the system to the landscape design was quite powerful. The planning system generates KML (Keyhole Markup Language) and VRML. KML file is visualized on Google Earth and VRML file can be visualized on stand alone computer. Plants were automatically placed on a terrain based on the data of GIS or Excel by using the system developed in this study. With the system, we made models of Koishikawa Korakuen Garden based on measured data. Performance of walk-through simulations was quite good. We proved that landscape visualization and simulation with Google Earth was possible and that the system can be used as a practical and low cost landscape simulation tool.
Bridge Launching Construction Visualized in a Virtual Environment
Authors: Martins Octávio P. , Sampaio Alcínia Z.
Published: October 2019

Virtual Reality techniques were used to develop an interactive application concerning the incremental launching construction of bridges, in the area of Civil Engineering. It was developed in order to facilitate understanding of the various phases involved in the construction. The visualization of the distinct physical steps of the construction is shown in the virtual application. The model makes it possible to view the physical evolution of the work, to follow the planned construction sequence and to visualize details of the form of every component of the work. It also supports the study of the type and method of operation of the equipment necessary for this construction activity. The application of visual simulation was designed to allow direct access to any stage of the constructive process in which it is based and may be viewed from any point within the virtual scene, thus facilitating their understanding. The access to the application can be established through a web page placed on the Internet. The model brings new perspectives in the training activity as a support to expose innovative methods or complex sequence construction.
A Motion-based User Interface for the Control of Virtual Humans Performing Sports
Authors: Liang Xiubo , Wang Zhen , Geng Weidong , Multon Franck
Published: October 2019

Traditional human computer interfaces are not intuitive and natural for the choreography of human motions in the field of VR and video games. In this paper we present a novel approach to control virtual humans performing sports with a motion-based user interface. The process begins by asking the user to draw some gestures in the air with a Wii Remote. The system then recognizes the gestures with pre-trained hidden Markov models. Finally, the recognized gestures are employed to choreograph the simulated sport motions of a virtual human. The average recognition rate of the recognition algorithm is more than 90% on our test set of 20 gestures. Results on the interactive simulation of several kinds of sport motions are given to show the efficiency and interestingness of our system, which is easy-to-use especially for novice users
Fostering Collaboration in Kindergarten through an Augmented Reality Game
Authors: Campos Pedro , Pessanha Sofia , Jorge Joaquim
Published: October 2019

Kindergarten children are a very special class of users, since they are in a primary stage of life, when they must learn how to live in society, e.g. to listen and respect the others' opinions, share the same objects and also help each other. This study presents an Augmented Reality game, in which kinder- garten children were able to collaborate in a spontaneous way supported by motivation, enjoyment and curiosity. This game allows children to explore concepts like the animals and the environments they live in by using Augmented Reality markers and a wooden board. These markers are the game pieces and through them children are able to manipulate 3D virtual models. Experiments were performed with several classes of students in different schools. Results suggest that the game is effective in maintaining high levels of motivation and collaboration among children, particularly when using immediate feedback
Entropy Based Information Visualization of Scientific Data
Authors: Wu Guoqing , Cao Yi , Yin Junping
Published: October 2019

Visualization of large scale time-varying scientific data has been a challenging problem due to their ever-increasing size. Identifying and presenting the most informative (or important) aspects of the data plays an important role in facilitating an efficient visualization. In this paper, an information assisted method is presented to locate temporal and spatial data containing salient physical features and accordingly accelerate the visualization process. Based on information measures, the method adaptively picks up important time steps and sub-regions with the maximum information content so that the time-varying data can be effectively visualized in limited time or using limited resources without loss of potential useful physical features. The experiments on the data of radiation diffusion dynamics and plasma physics simulation demonstrate the effectiveness of the proposed method. The method can remarkably improve the way in which scientists analyze and understand large scale time-varying scientific data
Fast Accelerometer-Based Motion Recognition with a Dual Buffer Framework
Authors: Shum Hubert P. H. , Komura Taku , Takagi Shu
Published: October 2019

The low-cost gyro-accelerometer based controllers have opened up a potential of using 3D computer games for serous applications such as sports and vocational training. Previous games apply simple template matching for motion recognition, which suffers from poor accuracy and time lag. In order to cope with these problems, we propose a novel dual buffer approach that dramatically increases the recognition rate and shortens the time lag for motion recognition. The system first recognizes the user control signal with a small buffer to minimize the time lag. When more signals arrive from the sensor, an elaborate recognition is performed, and the previously recognized action is switched if necessary. Using boxing as an example, we show that we can control a virtual character to perform 13 different actions using a buffer size of one-tenth of a second. Since our system is computationally inexpensive, it can be used in game consoles. As it is accurate and responsive, it can also be applied for serious sport training
Comprehensive Model and Image-Based Recognition of Hand Gestures for Interaction in 3D Environments
Authors: Bernardes J. , Nakamura R. , Tori R.
Published: October 2019

Interest in gesture-based interaction has been growing considerably, but most systems still limit the recognition of hand gestures to a small set of signs. We present a model for hand gestures that allows the definition of thousands of distinct signals based on the combination of a much smaller number of gesture components. This model comprehends several different kinds of gestures, both static and dynamic and using either hand or both. The choice of types of gestures and individual components is based not only on a review of the relevant literature but also on preliminary user studies, specifically for interaction in virtual and augmented environments and in entertainment and education applications. Gesture recognition based on this model is implemented as a finite state machine that incorporates the results of algorithms for the classification of each component, but is itself independent of those algorithms. The paper also describes an unencumbered gesture recognition system built using this model and recognition strategy, a single low-cost camera and relatively simple image-based algorithms to classify hand poses, movements and location and for segmentation. Tests show the model allowed the definition of the desired gestures for three target applications, a commercial computer game and two educational 3D environments. Our system was able to recognize these user gestures, and several others, in real-time. We could also perceive a need for the recognition of incomplete gestures and for a more robust segmentation strategy.
Learning Cultural Conversational Protocols with Immersive Interactive Virtual Humans
Authors: Babu Sabarish V. , Suma Evan , Hodges Larry F. , Barnes Tiffany
Published: October 2019

This paper reports on a study conducted to investi-gate the effects of using immersive virtual humans in natural multi-modal interaction to teach users cultural conversational verbal and non-verbal protocols in south Indian culture. The study was conducted using a between-subjects experimental design. We compared instruction and interactive feedback from immersive virtual humans against instruction based on a written study guide with illustrations of the cultural protocols. Partici-pants were then tested on how well they learned the cultural conversational protocols by exercising the cultural conventions in front of videos of real people. Subjective evaluations of participants' performance was conducted by three south Indian reviewers who were blind to the condition the participants were assigned. Objective evaluations of participants' performance were conducted on the motion tracking log data recorded during the testing session. We also measured the participants' pre and post positive and negative affect of training in both conditions, as well as the effect of co-presence with the life-size virtual south Indians. The results of our subjective evaluation suggest that participants who trained with the virtual humans performed significantly better than the participants who studied from literature. The results also revealed that there were no significant differences in positive or negative affect between conditions. However, overall for all participants in both conditions, positive affect increased and negative affect decreased from before to after instruction.
Fuzzy Feature Visualization of 3D Vector Field by Information-Entropy-Based Texture Adaptation
Authors: Wang Huaihui , Xu Huaxun , Zeng Liang , Li Sikun
Published: October 2019

Texture adaptation is a challenging issue in tex-ture-based feature visualization. In order to visualize as more information as we can, this paper presents a texture adaptation technique for fuzzy feature visualization of 3D vector field, taking into account information quantity carried by vector field and texture based on extended information entropy. Two definitions of information measurement for 3D vector field and noise texture, MIE and RNIE, are proposed to quantitatively represent the information carried by them. A noise generation algorithm based on three principles derived from minimal differentia of MIE and RNIE is designed to obtain an approximately optimal distribution of noise fragments which shows more details than those used before. A discussion of results is included to demonstrate our algorithm which leads to a more reasonable visualization results based on fuzzy feature measurement and information quantity.
Hybrid Silhouette Detection for Real-Time Shadow Volume
Authors: Kolivand Hoshang , Sunar Mohd Shahrizal
Published: October 2019

In shadow volume, the most expensive computation is silhouette detection. In this paper, the triangular algorithm (TA) and visible-non-visible (VnV) algorithm that are famous algorithms to detect the outline of occluder are renewed. In this paper, we proposed a hybrid algorithm based on TA and VnV, namely Hybrid Silhouette Detection (HSD) algorithm. HSD is an improved algorithm that can recognize silhouette for generating real-time shadow volume. Our algorithm involves detecting silhouette and decreases the cost of implementation for shadow volume rendering. The last shadow volume algorithm using stencil buffer is rewritten and an algorithm for shadow volume using HSD with respect of culling invisible parts of scene is proposed. An accurate mathematical comparison between TA, VnV and HSD algorithms is undertaken. The obtained results confirm superiority of our proposed algorithm in terms of processing and rendering time. Our algorithm can be used in virtual environment to increase the frame
Fast Image-Based Ambient Occlusion IBAO
Authors: Sajko Robert , Mihajlovic Zeljka
Published: October 2019

The quality of computer rendering and perception of realism greatly depend on the shading method used to implement the interaction of light with the surfaces of objects in a scene. Ambient occlusion (AO) enhances the realistic impression of rendered objects and scenes. Properties that make Screen Space Ambient Occlusion (SSAO) interesting for real-time graphics are scene complexity independence, and support for fully dynamic scenes. However, there are also important issues with current approaches: poor texture cache use, introduction of noise, and performance swings. In this paper, a straightforward solution is presented. Instead of a traditional, geometry-based sampling method, a novel, image-based sampling method is developed, coupled with a revised heuristic function for computing occlusion. Proposed algorithm harnessing GPU power improves texture cache use and reduces aliasing artifacts. Two implementations are developed, traditional and novel, and their comparison reveals improved performance and quality of the proposed algorithm.
Sketch Based Image Deformation and Editing with Guaranteed Feature Correspondence
Authors: Liu Yaqiong , Soon Seah Hock , He Ying , Lin Juncong , Xia Jiazhi
Published: October 2019

The establishment of a good correspondence mapping is a key issue in planar animations such as image morphing and deformation. In this paper, we present a novel mapping framework for animation of complex shapes. We firstly let the user extract the outlines of the interested object and target interested area from the input images and specify some optional feature lines, and then we generate a sparse delaunay triangulation mesh taking the outlines and the feature lines of the source shape as constraints. Then we copy the topology from the source shape to the target shape to construct a valid triangulation in the target shape. After that, each triangle of this triangular mesh is further segmented into a dense mesh patch. Each mesh patch is parameterized onto a unit circle domain. With such parametrization, we can easily construct a correspondence mapping between the source patches and the corresponding target patches. Our framework can work well for various applications such as shape deformation and morphing. Pleasing results generated by our framework show that the framework works well.
Interactive Extraction of Featuresin 3D Flow with Fuzzy Theory
Authors: Shen Enya , Xu Huaxun , Wang Wenke , Cai Xun , Zeng Liang , Li Sikun
Published: October 2019

Feature visualization plays an important role in vi-sualization of complicated flows because it can highlight the fea-ture of the flows with a simplified representation. The traditional feature visualization methods may exact some important features in flow field imprecisely due to the lack of the knowledge and the experience of the user. This paper gives a particle-based visuali-zation system which is developed with the application of the in-teractive fuzzy feature extraction and interactive visual analysis theories. To obtain a more precise feature extraction, we have proposed an interactive fuzzy feature description language (FFDL) and an interactive fuzzy feature extraction algorithm. Based on the work before, we introduced the proportion ration for different rules and optimized our algorithm in practice further by com-municating with specific researchers and doing lots of experi-ments. The further experiments show that our method can not only make full use of the ability of the user to extract the features precisely, but also reflect the uncertainty of the numerical simu-lation data.
Real-time Character Motion Effect Enhancement Based on Fluid Simulation
Authors: Xu Tianchen , Wu Enhua , Chen Mo , Xie Ming
Published: October 2019

In fast figure animation, motion blur is of crucial importance, and this is especially true when an artist wants to generate exaggerating effect through figure motion. For a quite long period of time, animators seek the answer by using certain kind of image blending, no matter by the means of hardware or software. In recent years, methods based on 3D geometry of the motion figure with global illumination become gradually in demand, as they could deliver relatively high quality of motion blur effect. However, the computation cost in those methods is always very high, thus real time rendering become quite difficult to achieve. In this paper, a real-time motion effect based on 3D geometric approach is proposed, in which a special effect along the motion trajectory based on fluid simulation is combined with the volumetric motion blur. Furthermore, the motion trajectory would be decomposed and multi-pass geometry rendering would be employed to achieve geometry instancing for reuse. In this manner, the redundant calculation of each frame could be avoided, and the limitation of trajectory generation would be broken. In the pipeline, we separate motion tracking and fluid solution, to support various fluid effects flexibly. The scheme we present makes use of GPU geometry shading in parallel, aiming at guaranteeing high efficiency of computation while delivering splendid rendering. As a result, real time rendering including the motion blur effect is achieved.
Advanced Material Rendering in Blender
Authors: Hatka Martin , Haindl Michal
Published: October 2019

Physically correct and realistic visual appearance rendering or analysis of material surface visual properties require complex descriptive models capable of modelling material dependence on variable illumination and viewing conditions. The recent most advanced representation of visual properties of surface materials is a Bidirectional texture function (BTF). BTF is 7D function of planar coordinates, spectral coordinate, and viewing and illumination angles, respectively. Unlike smooth textures, it specifies their altering appearance due to varying illumination and viewing conditions. This BTF visual appearance dependency on viewing and illumination conditions significantly complicates not only its acquisition, representation, and modelling but also makes its rendering noticeably more demanding. BTF textures are acquired by costly measurements of real materials and their subsequent nontrivial processing. While several techniques for measurement or processing of BTF textures have been described already, there is no environment allowing BTF texture rendering. This contribution describes novel Blender texture plugin for the purpose of BTF texture mapping and rendering. The plugin benefits from our previously developed BTF Roller texture enlargement method which is the integral part of its implementation. The presented plugin allows creating realistic computer animations with additional BTF textures of any required size mapped onto an object surfaces while the other functionality of Blender retains
Collision Detection for Point Cloud Models With Bounding Spheres Hierarchies
Authors: Figueiredo Mauro , Pereira João , Oliveira João , Araújo Bruno
Published: October 2019

Point cloud models are a common shape representation for several reasons. Three-dimensional scanning devices are widely used nowadays and points are an attractive primitive for rendering complex geometry. Nevertheless, there is not much literature on collision detection for point cloud models. This paper presents a novel collision detection algorithm for large point cloud models using voxels, octrees and bounding spheres hierarchies (BSH). The scene graph is divided in voxels. The objects of each voxel are organized intoan octree. Due to the high number of points in the scene, each non-empty cell of the octree is organized in a bounding sphere hierarchy, based on an R-tree hierarchy like structure. The BSH hierarchies are used to group neighboring points and filter out very quickly parts of objects that do not interact with other models. Points derived from laser scanned data typically are not segmented and can have arbitrary spatial resolution thus introducing computational and modeling issues. We address these issues and our results show that the proposed collision detection algorithm effectively finds intersections between point cloud models since it is able to reduce the number of bounding volume checks and updates