3D Virtual Space Research Articles

Correcting geometric distortions in stereoscopic 3D imaging.

Motion in a distorted virtual 3D space may cause visually induced motion sickness. Geometric distortions in stereoscopic 3D can result from mismatches among image capture, display, and viewing parameters. Three pairs of potential mismatches are considered, including 1) camera separation vs. eye separation, 2) camera field of view (FOV) vs. screen FOV, and 3) camera convergence distance (i.e., distance from the cameras to the point where the convergence axes intersect) vs. screen distance from the observer. The effect of the viewer’s head positions (i.e., head lateral offset from the screen center) is also considered. The geometric model is expressed as a function of camera convergence distance, the ratios of the three parameter-pairs, and the offset of the head position. We analyze the impacts of these five variables separately and their interactions on geometric distortions. This model facilitates insights into the various distortions and leads to methods whereby the user can minimize geometric distortions caused by some parameter-pair mismatches through adjusting of other parameter pairs. For example, in postproduction, viewers can correct for a mismatch between camera separation and eye separation by adjusting their distance from the real screen and changing the effective camera convergence distance.

Novel augmented reality interface using a self-powered triboelectric based virtual reality 3D-control sensor

Triboelectric nanogenerators and sensors have been widely adopted for diversified energy harvesting and sensing applications, but the demonstrations of 3D information sensing and controlling are very limited. In this paper, we present a novel self-powered virtual reality 3D-control sensor (VR-3D-CS) based on triboelectric mechanism for controlling the attitude (both the position and rotation) of object in 3D virtual space. This innovative, cost-effective, simple-designed sensor has a symmetric 3D structure with eight separated sensing electrodes and two touching spheres as the interactive interface with human fingers for 3D force information sensing and VR controlling. Based on the coupling effect of triboelectrification and electrostatic induction, the VR-3D-CS generates different electric output signals in response to different operation manner that can be used to control the attitude of objects in 3D virtual space. The symmetrical 3D configuration design of the sensor enables the detection of 3D force from both the normal direction and shear direction. By employing vector properties of force and signal analysis from the eight sensing electrodes, detection of six-axis directions in 3D space is achieved by triboelectric mechanism for the first time. The VR-3D-CS has been demonstrated to be able to detect normal force in the range of 0–18 N. It can resolve the shear force direction with step resolution of at least 15°. Besides, due to the positive output voltage and low internal impedance, the VR-3D-CS is readily compatible with commercial portable signal processing system for signal analysis and controlling. Demonstration of the VR-3D-CS as interactive interface for Augmented Reality (AR) control is successfully realized. The robust structure, stable output performance and self-powered sensing property enable the device as an ideal human machine interface towards AR interface, batteryless and energy saving applications.

Knowledgeability and modes of identification in (dis)embodied boundary practice in networked learning

Building on a continued interest in boundaries and boundary practice in relation to ICT-based networked learning (Ryberg & Sinclair, 2016), this paper addresses the issue of knowledgeability and identification through (dis)embodiment in design for boundary practice in networked learning. According to Goodyear (2015) teaching is about designing opportunities for people to learn, and from a learning perspective, how participants respond to design through their practices and through their use of boundary objects is interesting. Inspired by Wenger-Trayner & Wenger-Trayner’s (2015) concepts of knowledgeability and modes of identification, we analyse how two different case studies conducted at the Danish online Master programme on ICT and Learning (MIL) differ with regard to potential boundary practice and use of boundary objects. In study I, the design for learning was based on a 2D virtual learning environment (Dirckinck-Holmfeld, 2006), whereas the design for learning in study II was based on a 3D virtual world (Riis, 2016). Carlile (2002; 2004) proposed a hierarchical typology for boundary objects aiming at transfer, translation and transformation, and in our analysis, we identify examples of such boundary objects in the two learning arenas. Our findings show that all identified categories of boundary objects can mediate knowledge according to the typology. Nonetheless, certain boundary objects in the 3D learning arena (study II), in particular the avatar, seem to promote a different kind of embodied transformation, which has implications for identity formation of the participants. Furthermore, the 3D virtual space affords a concrete materialised, albeit virtual, opportunity for reification, which is different to that of the 2D environment. In the paper, we will elaborate on these differences, and based on the two case studies we propose that boundaries in networked learning should not only be regarded as socio-cultural differences, but as socio-material differences and dependencies as well. In particular, the materiality of a 3D virtual arena and avatars provides new relational and performative opportunities in networked learning.

2D Advertising in 3D Virtual Spaces

2D Advertising in 3D Virtual Spaces

Orientation measurement of graphically simulated nanoscale electrospun fibrous structures using particle-based modeling and 2-D metaball fitting

PurposeThe purpose of this paper is to provide an efficient tool for simulating electrospinning process in virtual 3D space and optimizing experimental parameters. The fiber orientation from virtual or real electrospinning process can be easily measured using the image analysis technique. Using the semi-implicit Euler integration, the time integration can be more fast and stable, which enabled optimization of the electrospinning process. Also boundary conditions can be easily adopted during conjugate gradient matrix solving step.Design/methodology/approachTo simulate the electrospinning process, the authors have adopted a particle-based modeling technique using the molecular dynamics theory, which is known to be suitable for modeling materials with nonlinear and nonhomogeneous behavior such as fibers or fabrics. Gravitational, tensional, and electrostatical forces and their Jacobians were carefully defined and chosen to maintain the stability of the governing equation. Preconditioned conjugate gradient method was used to solve the matrix iteratively with boundary conditions. The 2-D metaball fitting technique, which was applied in the previous research (Sul et al., 2009) on experimental nanofiber scanning electron microscopy images, was utilized with virtual nanofiber images. A staircase function and a new shading language were proposed to automatically calculate the orientation and radius distribution of the graphically simulated electrospun fiber structures. The automatic measurement procedure was verified via graphically designed virtual replica images. Also the orientation tendency acquired from the simulation was compared with that of experimental data.FindingsSimulation result of fiber orientation showed linear relationship with the collecting drum speed. Use of particle-based method generated a simple system to simulate electrospinning process.Originality/valueThe semi-implicit Euler integration was applied to the electrospinning process and the final linear system was numerically stable to solve.

Categorizing the Educational Affordances of 3 Dimensional Immersive Digital Environments

Aim/Purpose: This paper provides a general-purpose categorization scheme for assessing the utility of new and emerging three-dimensional interactive digital environments (3D-IDEs), along with specific pedagogic approaches that are known to work. It argues for the use of 3D-IDEs on the basis of their ludic appeal and ability to provide intrinsic motivation to the learner, and their openness that allows the learner to gain a more holistic understanding of a topic. Background: Researchers have investigated the affordances, benefits, and drawbacks of individual 3D-IDEs, such as virtual worlds, but teachers lack a general-purpose approach to assessing new 3D-IDEs as they appear and applying them to teaching practice. Methodology: The categorization scheme is based on the analysis, reflection, and comprehension of the research on limitations, challenges, and opportunities for teaching in virtual environments by Angel Rueda, Valdes Godines and Guzmán Flores; the scheme is discussed in terms of an experiment to trial virtual genetics labs in Second Life. Contribution: The paper describes a general-purpose approach to applying existing and new 3D virtual spaces to education, shows a worked example of the use of the categories, and describes six approaches to consider in applying these technologies. Findings: 3D-IDEs are categorized in terms of the way in which they interface with the user’s senses and their ability to provide ‘immersion’; two forms of immersion are examined: digital perceptual immersion – the generated sense of reality – and ludic narrative immersion – a less cognitive and more emotional engagement with the learning environment. Recommendations for Practitioners: Six specific forms of pedagogy appropriate for 3D-IDEs are examined and discussed, in terms of the affordances and technology required, as assessed by the categorization scheme. More broadly, the paper argues for a change in the assessment of new digital technologies from the technology’s features to its affordances and the pedagogies it can support. Recommendation for Researchers: The paper offers a practical approach to choosing and using 3D-IDEs for education, based upon previous work. The next step is to trial the scheme with teachers to ascertain its ease of use and effectiveness. Impact on Society: The paper argues strongly for a new approach to teaching, where the learner is encouraged to use 3D-IDEs in a ludic manner in order to generate internal motivation to learn, and to explore the topic according to their individual learning needs in addition to the teacher’s planned route through the learning material. Future Research: The categorization scheme is intended to be applied to new technologies as they are introduced. Future research is needed to assess its effectiveness and if necessary update the scheme.

Representation of three-dimensional space in the auditory cortex of the echolocating bat P. discolor.

The auditory cortex is an essential center for sound localization. In echolocating bats, combination sensitive neurons tuned to specific delays between call emission and echo perception represent target distance. In many bats, these neurons are organized as a chronotopically organized map of echo delay. However, it is still unclear to what extend these neurons can process directional information and thereby form a three-dimensional representation of space. We investigated the representation of three-dimensional space in the auditory cortex of Phyllostomus discolor. Specifically, we hypothesized that combination sensitive neurons encoding target distance in the AC can also process directional information. We used typical echolocation pulses of P. discolor combined with simulated echoes from different positions in virtual 3D-space and measured the evoked neuronal responses in the AC of the anesthetized bats. Our results demonstrate that combination sensitive neurons in the AC responded selectively to specific positions in 3-D space. While these neurons were sharply tuned to echo delay and formed a precise target distance map, the neurons’ specificity in azimuth and elevation depended on the presented sound pressure level. Our data further reveal a topographic distribution of best elevation of the combination sensitive neurons along the rostro-caudal axis i.e., neurons in the rostral part of the target distance map representing short delays prefer elevations below the horizon. Due to their spatial directionality and selectivity to specific echo delays representing target distance, combination sensitive cortical neurons are suited to encode three-dimensional spatial information.

Monitoring for Awareness and Reflection in Ubiquitous Learning Environments

ABSTRACTDespite the educational affordances that ubiquitous learning has shown, it is still hampered by several orchestration difficulties. One of these difficulties is that teachers lose awareness of what the students perform across the multiple technologies and spaces involved. Monitoring can help in such awareness, and it has been highly explored in face-to-face and blended learning. Nevertheless, in ubiquitous learning environments, monitoring has been usually limited to activities taking place in a specific type of space (e.g., outdoors). In this article, we propose a monitoring system for ubiquitous learning, which was evaluated in three authentic studies, supporting the participants in the affordable monitoring of learning situations involving web, augmented-physical, and 3D virtual world spaces. The work carried out also helped identify a set of guidelines, which are expected to be useful for researchers and technology developers aiming to provide participants’ support in ubiquitous learning environments.

Neural Correlates underlying Size Constancy in Virtual Three-Dimensional Space

The perceived size of an object remains relatively constant although its retinal size keeps decreasing as the object moves away along the depth dimension of the 3D space, i.e. size constancy. Neural mechanisms generating size constancy in virtual 3D space, however, remain poorly understood. By constructing a virtual 3D world in the MR scanner, we positioned the same 3D objects either near or far from the observers so that the near and far objects were perceived as having the same physical size despite their differences in retinal size. To control for the effect of differential retinal size, an additional 2D condition was introduced: a large and a small object, with matched retinal images as the near and far objects in the 3D condition, respectively, were presented on a 2D screen. Differences in retinal size activated overlapped areas in bilateral inferior occipital gyrus (IOG) in both experiments. The overlapped areas in IOG, however, showed different patterns of functional connectivity with different neural networks, depending on the perceived size of objects. In particular, IOG showed enhanced connectivity with bilateral superior parietal cortex in the 2D condition, but with inferior temporal and prefrontal cortex in the virtual 3D condition, i.e., size constancy.

日本における仮想空間「セカンドライフ」の利用実態 : 2つのSIMを事例に

日本における仮想空間「セカンドライフ」の利用実態 : 2つのSIMを事例に

Etiological factors in hallux valgus, a three-dimensional analysis of the first metatarsal

BackgroundIt has been reported that hallux valgus (HV) is associated with axial rotation of the first metatarsal (1MT). However, the association between HV and torsion of the 1MT head with respect to the base has not been previously investigated. The present study examined whether there was a significant difference in 1MT torsion between HV and control groups.MethodsThree-dimensional (3D) computed tomography (CT) scans of 39 ft were obtained, and 3D surface models of the 1MT were generated to quantify the torsion of the head with respect to the base. The HV group consisted of 27 ft from 27 women (69.5 ± 7.5 years old). Only the feet of HV patients with an HV angle >20° on weight-bearing radiography were selected for analysis. The control group consisted of 12 ft from 12 women (67.7 ± 7.2 years old). In a virtual 3D space, two unit vectors, which describe the orientation of the 1MT head and base, were calculated. The angle formed by these two unit vectors representing 1MT torsion was compared between the control and hallux valgus groups.ResultsThe mean (± standard deviation) of the torsional angle of the 1MT was 17.6 (± 7.7)° and 4.7 (± 4.0)° in the HV and control groups, respectively, and the difference was significant (p < 0.01).ConclusionsThis is the first study, to the best of our knowledge, to investigate 1MT torsion in HV patients using CT-based 3D analysis. The 1MT showed significant eversion in hallux valgus patients compared to control group patients.

QoE Assessment of Fairness between Players in Networked Virtual 3D Objects Identification Game Using Haptic, Olfactory, and Auditory Senses

In this paper, we carry out QoE (Quality of Experience) assessment to investigate influences of olfactory and auditory senses on fairness for a networked virtual 3D object identification game with haptics. In the game, two players try to identify objects which are placed in a shared 3D virtual space. In the assessment, we carry out the game in four cases. Smells and sounds are presented in the first case, only sounds are done in the second case, and only smells are done in the third case. In the last case, we present neither smell nor sound. As a result, we demonstrate that the fairness deteriorates more largely as the difference in conditions between two users becomes larger.

Empty Room, how to compose and spatialize electroacoustic music in VR in ambisonic and binaural

Presentation of the Empty Room project, dedicated to the exploration of new musical composition and spatialization methods in virtual 3D spaces developped on multiplayer or mono player technologies such as Second Life, Open Simulator and Unity 3D, using the latest video game and virtual reality technologies.

Evaluation of Armhole Lines of Blouses Using 3D Virtual Fitting and Human Subjects

There are relatively few studies on functional and appealing armhole lines of a blouse761, due to the complex shape of the shoulder and armpit. In this study, we investigated the functionality of eight different armhole lines, using human subjects as well as virtual fitting. The primary goal of this study was to determine which armhole line is suitable to the movement of a shoulder joint with an acceptable appearance. Next, we studied whether subtle differences in armhole lines affect the shape of the blouse in 3D virtual space. Finally, we analyzed if the wear test evaluations for mobility matched the corresponding shape deformation observed by the displacement of reference points of the 3D virtual blouse. We observed that the amount of displacement of the reference points as shown by 3D virtual fitting, matched the wearer’s evaluation of the functional aspects of the blouse during shoulder joint movement.

3차원 가상공간 내 가시분석 데이터 추적 및 그래픽 구현 기술 개발에 관한 연구

Three-dimensional visibility techniques have been developed mainly in targeting the analysis of spatial volumes as well as the surfaces, such as, floors, walls and building facades. It is however difficult to apply these kinds of techniques into more sophisticated 3D visibility analysis because it has not been reported the way how to trace the details of analysed results due to a lack of searching process techniques of those in 3D virtual space. This study is therefore to develop 3D visibility data tracing and graphically representing technique in a 3D virtual space. Our approach employs a reverse process of multi-layer rendering algorithm to perform the picking operation in the 3D visibility analysis process. Two techniques are formulated: a dynamic view frustum of the screen following user instruction under the virtual camera installed in 3D space together with ray-picking algorithm and a reverse process of 3D projection for rendering. This data searching technique in 3D virtual space helps to interpret and simulate of design layout more precisely, as well as to pin point and present the analyzed 3D visibility data accurately.

Fast and Forceful: Modulation of Response Activation Induced by Shifts of Perceived Depth in Virtual 3D Space.

Reaction time (RT) can strongly be influenced by a number of stimulus properties. For instance, there was converging evidence that perceived size rather than physical (i.e., retinal) size constitutes a major determinant of RT. However, this view has recently been challenged since within a virtual three-dimensional (3D) environment retinal size modulation failed to influence RT. In order to further investigate this issue in the present experiments response force (RF) was recorded as a supplemental measure of response activation in simple reaction tasks. In two separate experiments participants’ task was to react as fast as possible to the occurrence of a target located close to the observer or farther away while the offset between target locations was increased from Experiment 1 to Experiment 2. At the same time perceived target size (by varying the retinal size across depth planes) and target type (sphere vs. soccer ball) were modulated. Both experiments revealed faster and more forceful reactions when targets were presented closer to the observers. Perceived size and target type barely affected RT and RF in Experiment 1 but differentially affected both variables in Experiment 2. Thus, the present findings emphasize the usefulness of RF as a supplement to conventional RT measurement. On a behavioral level the results confirm that (at least) within virtual 3D space perceived object size neither strongly influences RT nor RF. Rather the relative position within egocentric (body-centered) space presumably indicates an object’s behavioral relevance and consequently constitutes an important modulator of visual processing.

Velocity Selective Networks in Human Cortex Reveal Two Functionally Distinct Auditory Motion Systems.

The auditory system encounters motion cues through an acoustic object’s movement or rotation of the listener’s head in a stationary sound field, generating a wide range of naturally occurring velocities from a few to several hundred degrees per second. The angular velocity of moving acoustic objects relative to a listener is typically slow and does not exceed tens of degrees per second, whereas head rotations in a stationary acoustic field may generate fast-changing spatial cues in the order of several hundred degrees per second. We hypothesized that these two types of systems (i.e., encoding slow movements of an object or fast head rotations) may engage functionally distinct substrates in processing spatially dynamic auditory cues, with the latter potentially involved in maintaining perceptual constancy in a stationary field during head rotations and therefore possibly involving corollary-discharge mechanisms in premotor cortex. Using fMRI, we examined cortical response patterns to sound sources moving at a wide range of velocities in 3D virtual auditory space. We found a significant categorical difference between fast and slow moving sounds, with stronger activations in response to higher velocities in the posterior superior temporal regions, the planum temporale, and notably the premotor ventral-rostral (PMVr) area implicated in planning neck and head motor functions.

Pedagogic transformation, student-directed design and computational thinking

ABSTRACTIn a world where technology has become pervasive in our lives, the notion of IT integration in education practice is losing its significance. It is now more appropriate to discuss transforming pedagogy where technology is not considered a tool anymore but part of what we are. To advance this hypothesis, an enterprising, student-directed approach is proposed which embraces problem-solving as activity and computational thinking as knowledge development. In order to test its efficacy, a case study of students developing a 3D virtual space for international collaboration is used to exemplify the transformational pedagogy. From observations of the enactment of heutagogical characteristics and computational thinking, it is argued that we can now teach and learn “in” technology. This modality will come to dominate how technology operates “as” our lives, and become central to what it means to know and learn.

혼합증강현실에서 라이브 행동자와 실체 표현을 위한 표준 모델

/012345#2367458 9(:67&; 45#67458=?@A&BCB.  45 DE ? !#$(LAE: live actor and entity)63D 67F :=>GHIJ%K3LMN, OP3D QRS, 3D 67$TUV WHX 6Y=B. Z [  ?LAE83D 67F GHIJ=\, ] ]7^A_3*+&%) `(B. `(*+&/aM]LAES:7^A 3 K3LB.AbstractMixed and augmented reality technique deals with mixing content between real world and virtual world containing augmented reality and augmented virtuality excluding of pure real and pure virtual world. In mixed and augmented reality, if a live actor and entity moving in real world can be embedded more naturally in 3D virtual world, various advanced applications such 3D tele-presence, 3D virtual experience education and etc can be serviced. Therefore, in this paper, we propose a standard model which is supporting to embed the live actor and entity into 3D virtual space, and to interact with each other. And also the natural embedding and interaction of live actor and entity can be performed based on the proposed model. Keyword : Mixed and augmented reality, live actor and entity, spatial mapping, event mapping

Simple reaction time and size–distance integration in virtual 3D space

Simple reaction time to visual stimuli depends on several stimulus properties. Recently, converging evidence showed that larger stimulus size evokes faster reactions and that this effect seemingly depends on the stimulus' perceived size rather than on physical stimulus properties. Size-distance scaling usually is regarded as the main functional mechanism underlying size perception. Yet, the role of stimulus depth (distance to a target) has often been neglected in previous studies. Hence, in the present investigation, stimuli were generated using stereo head mounted displays to manipulate stimulus depth. In Experiment 1, a large or small target was presented within the center of a reference plane, either in the same depth plane or displaced (near, far) while participants had to perform a simple reaction time task. At the same time, the target was modulated such that either retinal size was constant or variable across depth planes. In Experiments 2 and 3 the reference plane was shifted along with the target (blocked or on a trial-by-trial basis), while retinal size modulation was equal to Experiment 1. As expected, participants reacted faster to physically larger targets. Also Experiment 1 revealed faster reaction times for closer targets, while the commonly described connection between perceived size (i.e., size-distance scaling) was not apparent in any experiment. Thus, unlike past findings using a virtual three-dimensional task-setting (as induced by binocular disparity) reaction times are not affected by variations of perceived stimulus size.