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Article type: Cover
Pages Cover1-
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (15K) -
Article type: Index
Pages Toc1-
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (86K) -
Koichi Hirota, Atsuko Tanaka, Toyohisa KanekoArticle type: Article
Session ID: HIR99-41/NIM99-66
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIt is a common approach to simulate the colliding force by defining an ideal fingertip that moves while satisfying physical constraints. In the approach, the constraint force is obtained from the disparity between the real and ideal fingertips. In this paper, we propose a method of simulating the motion of the ideal fingertip in virtual environment. To represent spatial variation of the material, we divided the space into tetrahedral elements and defined the characteristics of the element. The movement of fingertip in an element is simulated on the basis of physical constraint. Fingertip transfer between neighboring elements and the change of bound state on the boundary is described by introducing the idea of state transition. We implemented the proposed method, estimated the computation time, and proved that the method is fast enough for the application to real-time simulation.View full abstractDownload PDF (916K) -
Yasushi Ikei, Shunsuke Goto, Shuichi FukudaArticle type: Article
Session ID: HIR99-42/NIM99-67
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThis paper describes a method to calculate contact behavior and a haptic feedback of a rigid body which is manipulated by the user. The contact of a manipulated object to a surface with a complicated geometrical variation or texture is calculated based only on statics and an approximated coefficient of friction without using an exact geometric model of the surface. The variation on the surface is substituted by the coefficient of friction which is obtained approximately by applying a linear derivative filter to a surface height map measured by a laser displacement meter. The haptic impressions on resultant feedback forces were evaluated as compared to the direct touch with a fingertip to the real texture surfaces and to the indirect touch with a stick. The result showed that the method was better applicable to the surfaces with a relatively high spatial frequency and a small height difference.View full abstractDownload PDF (1047K) -
Nobuyuki KUKIMOTOArticle type: Article
Session ID: HIR99-43/NIM99-68
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSRecently the quality of graphics activity was grown up and it gave high reality to user. And many VR systems has controller devices user controls it for translate the virtual world. But this way user feels controlling rather than translating, and it is discomfort similar simulator sickness. This problem cause user does not move their body. To move any part of body will reduce this problem. I designed new way of walk through the virtual world that a computer measurse users shaking arm like walking. The translation speed will be changed by shaking speed. User does not feel out and does not report discomfort because their motion and visual information was united.View full abstractDownload PDF (647K) -
Kingo Koyama, Yasuyuki Yanagida, Taro Maeda, Susumu TachiArticle type: Article
Session ID: HIR99-44/NIM99-69
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn this paper, we study on the eye-hand tracking movements under the following two conditions of target display. As the first one, the target was displayed visually. This condition is popular to study on eye and hand movements. As the other one, the target was displayed on the subject's hand tactually. Compared the results of the experiments under these conditions, the model for the human sensori-motor system, that there is a part of the human brain which integrates all of the position information of human body, is not proper.View full abstractDownload PDF (477K) -
Daisuke Komaki, Hirotake Ishii, Nobuyuki Ichiguchi, Hiroshi Shimoda, H ...Article type: Article
Session ID: HIR99-45/NIM99-70
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe purpose of this study is to propose a new effective method to synthesize a natural human body motion in virtual reality. The following experimental studies were conducted especially about human walk motion. (1) Actual human walk motions were measured by using a 3D motion capturing system, and the features of the joints motion were analyzed from the correlations of joint angle transients. (2) The factors which represent the naturalness of human body motion were investigated by 10 subjects'questionnaires after showing various walk motions. As the results of the former study, for example, we found shoulder joints motion and waist twisting motion are similar to each other. As the results of the latter study, we found leg's motion is much more important for human walk motion than the motion of upper half of the body. Then, a new synthesis method has been proposed from the results of the above experimental studies.View full abstractDownload PDF (869K) -
Hirotaka Takahashi, Masahiko Inami, Yasuyuki Yanagida, Taro Maeda, Sus ...Article type: Article
Session ID: HIR99-46/NIM99-71
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSA locomotion interface which is made to walk around in Virtual Environments has been planned for a viewpoint that how we can cancel a distance of walk, for a walkspace was regarded as important. We aimed at the viewpoint which a sense of walk is regarded as important and examined how much we need a total length of the walkspace. As a result, the length of a plan which one cannot judge properly was up to 55m, and if one doesn't stop walking, its length was up to 20m, and a plan which one's walk wouldn't be disturbed was up to 6m.View full abstractDownload PDF (525K) -
Taku Kosuge, Haruo Noma, Tsutomu MiyasatoArticle type: Article
Session ID: HIR99-47/NIM99-72
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThese days sportscast on TV has become the most popular program. In this paper, we introduce new method for realistic sportscast based on player's view that means all what sports player is feeling. Especially, we focused on the marathon here. We built trial system and examined effectiveness of the method through simulation of the relay sportscast of marathon. As the results, we find that the subjects felt more aggressive feeling while they tried the marathon program with our method than ordinal method.View full abstractDownload PDF (1045K) -
Masahiko INAMI, Naoki KAWAKAMI, Dairoku SEKIGUCHI, Yasuyuki YANAGIDA, ...Article type: Article
Session ID: HIR99-48/NIM99-73
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSConventional Telexistence system is now possible to telexist in the remote environment and/or virtual environment with a sensation of presence. We can have feelings that we are present in several real places and can work and act. However, those people in the place where someone telexists using a robot see only the robot but they can not feel that the person who presents. In this paper, we propose the new type Telexistence system using optical projection type Object-Oriented Display. This system allows a remote robot painted retroreflector to display operator's image.View full abstractDownload PDF (801K) -
Kenji SUZUKI, Kenji TANAKA, Ryutaro SUZUKI, Yoshiki ARAKAWA, Tetsuro O ...Article type: Article
Session ID: HIR99-49/NIM99-74
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESS4-Point Discussion Space System, a virtual space which connects four remote institutes, has been constructed at Communications Research Laboratory (CRL) as part of the Multimedia Virtual Laboratory (MVL) project. In this system CRL, the University of Tokyo, Tsukuba University and National Institute of Multimedia Education (NIME) are connected with 75Mbps ATM networks. By reproducing eye contact and voice directions, the constructed virtual space presents an environment where four people in four different institutes can have natural conversation with one another as if they are in the same room.View full abstractDownload PDF (1113K) -
Michitaka Hirose, Tetsuro Ogi, Toshio Yamada, Ken Tamagawa, Sungyoon K ...Article type: Article
Session ID: HIR99-50/NIM99-75
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe immersive projection display, CABIN was connected to several similar displays via ATM network. In this networked system, virtual world can be shared with high quality of presence between remote sites. The user's figure is captured and superimposed on the shared image as video avatar. In this paper, 3 eyes camera Triclops was introduced to extract human image from changeable image by depth image in CABIN.View full abstractDownload PDF (705K) -
Michiya Yamamoto, Daiji Iwata, Tetsuo Tezuka, Hidekazu YoshikawaArticle type: Article
Session ID: HIR99-51/NIM99-76
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThe Distributed Virtual Environment (DVE) is expected as a promising communication technology in the future. And, the productivity enhancement of DVE system is important subject for the progress of DVE. In this study, we proposed a new method for expanding DVEs consistently, and constructed a DVE system as a prototype system, which we call EX-DVE system. EX-DVE is a DVE where users can easily add virtual objects into the existing DVE, that is, can EXpand the DVE. First, we designed the hybrid modeling method for DVE simulation. This method consists of 1. data set, which logically express physical state of virtual object 2. simulation method, which physically enables interaction between virtual objects. The data set is composed of hierarchical structure, so that users can reuse the data of existing virtual objects. Second, the EX-DVE system is a prototype system to confirm that the hybrid modeling enables users to add virtual objects consistently into DVE. The basic tasks for machine assembly and disassembly are realized in this system. By using the EX-DVE system, multiple users can not only communicate with each other by visual and audio information, but also independently expand the DVE.View full abstractDownload PDF (861K) -
Katsuyuki Kamei, Kazuo SeoArticle type: Article
Session ID: HIR99-52/NIM99-77
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn this paper, we propose a new scene representation method named PAS-Movie which replays an actual scene using a video sequence. Basically, our method generates views in the scene by using video frames in sequence, in order to keep natural motions in it such as sway of branches. And, in order to accomplish arbitrary walk (such as change of step or moving right and left) in the scene, the frames are scaled, translated or skipped according to the user's occasional viewpoint. By these operations, both of generating a natural scene and performing a virtual walk in it can be easily carried out. We have examined the error of the generated view, which gives the condition whether frames would be skipped or not. An extension of our method is also described which uses multiple streams of video sequences for improving the quality of the generated views. Our experimental results show the usefulness of our method.View full abstractDownload PDF (1130K) -
Tomohiro Tanikawa, Takaaki Endo, Michitaka HiroseArticle type: Article
Session ID: HIR99-53/NIM99-78
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThis paper describes a new approach for building a photo-realistic virtual world from the real world. By using a vehicle-mounted image capturing system, we have constructed a huge image database with global position and orientation information. But to have every image from various viewpoints is resource-exhaustive. So, image generation from finite image data sets is an important topic. For this purpose, view-dependent "subjective" virtual space is sufficient, and "objective" virtual space isn't necessary. Based on this idea, we propose a "view-dependent image projection" method and a "3-D layer presumption" method to generate a "subjective" virtual space, and implement a photo-realistic virtual world by applying these methods to the image database. Both methods can construct only a local model of the whole virtual world, but by changing local models according to the viewpoint, the user can move inside a wider area. It is proved that this kind of subjective model is practically sufficient to develop a wide-range photo-realistic virtual world.View full abstractDownload PDF (1298K) -
Xiaohui ZHANG, Masayuki NAKAJIMAArticle type: Article
Session ID: HIR99-54/NIM99-79
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn computer graphics (CG), the illuminance computing is the most time consuming process. Especially when the realism is considered, texture mapping, bump mapping, ray tracing, radiosity, and daylight simulation must be used. Though those techniques improve the realism, at the same time they make the real-time interaction impossible. In this paper, an Image-Based Daylight Simulation (IBDS) technique is used to accelerate the rendering process of CG. First, from two CG generated outdoor images, the sky-factor and reflectance parameters are recovered. Then using these parameters, this technique can quickly produce new images, and simulate different weather conditions from a clear day to a cloudy day without computing illuminance for each frame. The speed of rendering is greatly increased, and make the real-time interaction possible.View full abstractDownload PDF (1087K) -
Xiaohua Zhang, Masayuki NakajimaArticle type: Article
Session ID: HIR99-55/NIM99-80
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSWe propose a new method for generating visual stereo images from the common two dimensional images without 3D reconstruction. The major novel contributions of this report are in two aspects. First, we address the dominant motion detection presented in the given scenes, for doing so we borrow phase shift theorem and calculate the inverse Fourier transform of cross-power spectrum to find the maximum peak value whose position can be used to decide motion parameters. Secondly, unlike most of researchers study the stereo vision to recover 3D information for modeling and rendering, we address the visual stereo image generation without 3D reconstruction just applying the computed motion parameters to make decision of selecting two given images for left eye and right eye individually. The proposed approaches can be employed for applications such as navigation in a virtual environment.View full abstractDownload PDF (1009K) -
Hiroaki Shigemasu, Takao SatoArticle type: Article
Session ID: HIR99-56/NIM99-81
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSIn stereo pictures, objects and people often appear flat like cardboard cut-outs. Previous study suggests that this phenomenon occurs because of near viewing distance and disparity discontinuity between objects and backgrounds. In experiment 1, we investigated whether the inhibition of depth perception from disparity discontinuity is caused by depth contrast or binocular rivalry. The results show that the inhibition is caused by lateral inhibition of classical center-surround mechanism, which underlie depth contrast effect. Thus, the mechanism of depth contrast is analogous to those of luminance domain. In experiment 2, the effect of vergence angles on disparity detection was investigated. In results, it is more sensitive to disparity when vergence angle becomes smaller. This results suggest that the sensitivity of disparity is modulated by vergence. Because binocular disparity vary inversely with the square of the distance, this hypothesis is ecologically valid to keep depth constancy.View full abstractDownload PDF (634K) -
Koh Kakusho, Jun Kitawaki, Shiro Hagihara, Michihiko MinohArticle type: Article
Session ID: HIR99-57/NIM99-82
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThis paper discusses how to cope with failures by humans in manipulating objects in three dimensional (3D) virtual space represented by stereoscopic images with binocular disparity. Although stereoscopic images are very useful representation to visualize the depth of 3D virtual space in a computer, it is not easy for us to manipulate each virtual object precisely based on its stereoscopic images given by stereo viewing devices. One of the reasons why this difficulty occurs is that the depth recovered from stereoscopic images of 3D virtual space in the process of human visual perception is not exactly the same as the space because human visual perception is affected not only by binocular disparity but also by various kinds of factors including accomodation. As the result, manipulation of virtual objects often fails due to the difference of human perception from the virtual space in a computer. In this article, we propose to deform the virtual space so that it becomes consistent with the space perceived by each user based on the result of the user's manipulation, especially pointing the surface of each virtual object and moving that object. The experimental results show that manipulation with this modification is about four times as successful as that without modification.View full abstractDownload PDF (1274K) -
Kazushi Maruya, Toshio Kubodera, Takao SatoArticle type: Article
Session ID: HIR99-58/NIM99-83
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSWe investigated mechanisms mediate motion perception of missing fundamental (MF) gratings at interstimulus intervals (ISIs) of about 40 ms. At ISIs grater than about 40ms, apparent motion for MF gratings was perceived in the direction of displacement (Georgeson & Harris, 1990^<[1]>). At ISIs greater than about 160msec, clearer apparent motion in the direction of displacement is perceived when exposed in lower visual field than in upper visual field (Mugishima & Sato, 1998^<[2]>). However, there is no asymmetry between the upper and lower visual field at ISIs of about 40 ms. This asymmetry suggests the participation of the process of feature tracking in motion detection. Therefore, there seems no contribution of the feature tracking process at these ISIs. In Experiment 1, no motion aftereffect was induced after adaptation to apparent motion using MF grating at ISIs 40ms. In Experiment 2, attention was divided by dual task. One is direction discrimination of apparent motion using MF grating presented peripheral visual field. The other is to read English letters presented central visual field. The result was that apparent motion was seen in the reversed direction under all conditions at ISIs 20-160 ms. These results suggest (a) a higher-order motion detection mechanisms mediate apparent motion in the direction of displacement at ISIs of about 40 ms, and (b) attention plays some role in these mechanisms in the different manner of featuretracking.View full abstractDownload PDF (669K) -
Jun'ichiro Seyama, Takao SatoArticle type: Article
Session ID: HIR99-59/NIM99-84
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSSlant aftereffect (SAE), the negative aftereffect of slant induced after the prolonged observation of a surface, was considered as evidence that slant is encoded in the visual system. Because slant and tilt are mathematically independent dimensions, Stevens (1983a) assumed that slant and tilt are processed independently in the visual system. To confirm this assumption, we investigated whether SAE is induced independently of the difference in tilt between the adapting and test stimuli. The stimuli were displayed by simulating the motion disparity of rotating disks. After adaptation to a surface of 60° slant, the subjective 0° slants of the test stimulus were measured with the tilt difference of 0°, 45°, 90°, 135° and 180°. The magnitude of SAE was maximum when the tilt difference was zero, and decreased with increasing tilt difference. The results suggest that slant and tilt are not processed independently in the visual system and that the slant detector in the visual system is sensitive not only to slant but also to tilt.View full abstractDownload PDF (476K) -
Toshihiro Masaki, Tetsuya Yamaguchi, Yoshifumi Kitamura, Fumio KishinoArticle type: Article
Session ID: HIR99-60/NIM99-85
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSThis paper describes a simplified real-time 3D modeling technique for objects extracted from video images by an efficient algorithm in order to produce multimedia contents. An object contained in video images which is extracted at a reasonable speed is reconstructed in a proposed augmented virtuality system with sufficient accuracy. Moreover, real object interactions that meet such criteria must be established using techniques for manipulating objects in virtual worlds. The proposed technique has potential to generate novel multimedia contents without using complicated shape modeling. An interactive digital fishtank is described as one example application of the proposed technique. In this application, the user is able to obtain augmented virtuality world of fishtanks from the original video sequence.View full abstractDownload PDF (984K) -
Article type: Appendix
Pages App1-
Published: June 07, 1999
Released on J-STAGE: June 23, 2017
CONFERENCE PROCEEDINGS FREE ACCESSDownload PDF (85K)
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