The walking excavator is a highly complex construction machine, characterized by challenges in control, instruction, and operational safety. In this work, we implemented a virtual reality (VR) walking excavator simulator that integrates real hardware components with kinematic physics simulation. Using the simulator, we conducted two user studies. The first involved 45 participants and examined the effects of user perspectives on performance and preference. The second involved 12 participants and investigated the influence of video passthrough of the controllers. Results show that the choice of perspective should be task-dependent. Third-person view outperformed first-person view in the undercarriage task in which complex leg movements are needed. It supported better planning and allowed complete body visualization. However, it did not reduce motion sickness and was less preferred than first-person view for training. From the second user study, passthrough significantly improved controller learning compared to animated controllers, with participants making fewer errors when using the passthrough design. Based on these findings, we provide design recommendations for user perspectives and controller representation in VR-based training simulators.

Visualization of complex architectural and interior design proposals demands spatial perspective taking (SPT), an ability that can be difficult to acquire. Mixed Reality (MR) is particularly effective in architectural visualization because it overlays virtual models onto already existing real environments, allowing for precise spatial accuracy and aesthetic assessment. However, MR confines users to viewpoints tied to locations they can physically reach in the real-world. To overcome this constraint, we designed an applied, visibility-driven SPT task and explored two methods to provide additional perspective cues in MR: the World-in-Miniature (WIM) mode and the Cross Reality (CR) mode. The WIM mode provides a scaled-down 3D replica of the virtual environment, allowing users to explore a design at a reduced scale. Conversely, the CR mode allows switching from MR to VR to hide the real-world completely, enabling users to teleport to physically unreachable viewpoints and assess a design at an accurate scale. We conducted a pilot user study with 14 participants and a formal user study with 80 participants on an object-placement task. Our results revealed that the CR mode achieved success scores as high as those of the WIM mode. The WIM mode was faster and perceived as more user-friendly. However, participants preferred the CR mode for its accurate spatial representation and effective presentation of design ideas. The CR mode recreates the physical room as a scale-accurate virtual counterpart, preserving geometric cues critical for spatial visualization while removing the need for manual room modeling. Our findings highlight the potential of these modes to transform 3D design visualization and set new standards in the industry.

Modern Mixed Reality Head-Mounted Displays (MR-HMDs) can track user movements across large spaces without external markers. This study evaluates the tracking accuracy and the loop closure capabilities of four commercially available MR-HMDs across four distinct scenarios. We found consistent tracking performance in well-lit and expansive environments for all devices. Tracking accuracy remained stable even in outdoor nighttime conditions. Furthermore, most HMDs demonstrated effective error correction during loop closure, with errors in non-loop scenarios consistently exceeding those in loop scenarios.

This paper introduces a collaboration setting where an expert in VR gives instructions to a technician using MR being in front of the real object. For this study, we develop a system in which users communicate while building a specific structure using Lego Duplo blocks. Here, only the expert knows the final configuration and instructs the technician equipped with an MR headset about the assembly. Four communication methods are evaluated: voice chat, avatars, the possibility of moving virtual blocks similar to the real ones, and an arrow functionality. This work proves the usefulness of such a VR/MR instruction system and provides insights into the advantages of each proposed communication method.

Redirected Walking (RDW) is a common technique leveraged to allow real walking for exploring large virtual environments in constrained physical tracking spaces. Effective RDW is challenging due to its complexity and disturbance factors (e.g., spontaneous user behavior). Existing techniques range from combinations of simple motion scaling to more elaborate curvature injections and reactive, predictive, or scripted steering concepts. However, many of these approaches were evaluated in simulation only, and researchers argued that the findings would translate to real scenarios to motivate the effectiveness of their algorithms. Using the Redirected Walking Toolkit and its virtual path generator, a randomized waypoint-based path generator has been common practice, although its built-in simplifications assume sequential user behavior regarding translation and rotation.In this paper, we argue that pure simulation-based evaluations employing such simplified path generators require critical reflection. We demonstrate RDW simulations that show the chaotic process fundamental to RDW, in which altering the initial user’s position by mere millimeters can drastically change the resulting steering behavior. This insight suggests that RDW is more sensitive to the underlying data than previously assumed. Thus, we rigorously analyze the influence of commonly used synthetically generated paths on multiple state-of-the-art steering concepts and compare them against previously recorded real paths.

Virtual Reality (VR) headsets can open opportunities for users to accomplish complex tasks on large virtual displays using compact and portable devices. However, interacting with such large virtual displays using existing interaction techniques might cause fatigue, especially for precise manipulation tasks, due to the lack of physical surfaces. To deal with this issue, we explored the design of VXSlate, an interaction technique that uses a large virtual display as an expansion of a tablet. We combined a user’s head movements as tracked by the VR headset, and touch interaction on the tablet. Using VXSlate, a user head movements positions a virtual representation of the tablet together with the user’s hand, on the large virtual display. This allows the user to perform fine-tuned multi-touch content manipulations. In a user study with seventeen participants, we investigated the effects of VXSlate on users in problem-solving tasks involving content manipulations at different levels of difficulty, such as translation, rotation, scaling, and sketching. As a baseline for comparison, off-the-shelf touch-controller interactions were used. Overall, VXSlate allowed participants to complete the task with completion times and accuracy that are comparable to touch-controller interactions. After an interval of use, VXSlate significantly reduced users’ time to perform scaling tasks in content manipulations, as well as reducing perceived effort. We reflected on the advantages and disadvantages of VXSlate in content manipulation on large virtual displays and explored further applications within the VXSlate design space.

The main goal of Virtual Training Environments (VTEs) is to maximize training effectiveness, which can be achieved by increasing the degree of immersion. While prior work mainly focused on the visual, auditory, and navigational aspects of immersion, proprioceptive aspects may be particularly important. In this work-in-progress paper, we explore this potential by implementing an industrial VTE, which can be interacted with, using VR gloves and a tracked real tool. Further, we evaluate the VTE in a pilot study with industry apprentices, providing initial evidence that participants experienced high presence and low task load, while being generally satisfied with the training.

Redirected walking (RDW) allows users to explore a virtual environment larger than the physical tracking space by real walking. When RDW is applied within certain thresholds, users do not notice it and remain immersed in the virtual environment. There are many factors that affect these thresholds such as walking speed, gender, and field of view. However, redirected walking thresholds (RDTs) were never studied when an avatar is present, and it is not known how the sense of embodiment over this avatar affects users’ RDTs.

One of the main characteristics of virtual reality (VR) is immersion, which leads to comprehensive illusions of reality. Accordingly, VR is used in many applications like entertainment, marketing, and training. Especially in training applications, the effect of immersion on training success is still not entirely clear, since too much immersion may cause side effects such as users experiencing high mental demand whereas too little may disturb users’ well-being. To further investigate the matter, we developed two virtual training environments, wherein users train a typical industrial assembly task either in low or high immersive VR. In a controlled pilot study, we additionally introduced a third condition, the control group, which justifies the necessity of the training. Immediately after the VR training session, each participant completed the corresponding real assembly task in which their performance was measured. Preliminary results from our pilot study show that participants trained in high immersive VR performed better, while negative side effects could not be detected.

Abstract This paper presents a brainstorming tool combined with pointing gestures to improve the brainstorming meeting experience for blind and visually impaired people (BVIP). In brainstorming meetings, BVIPs are not able to participate in the conversation as well as sighted users because of the unavailability of supporting tools for understanding the explicit and implicit meaning of the non-verbal communication (NVC). Therefore, the proposed system assists BVIP in interpreting pointing gestures which play an important role in non-verbal communication. Our system will help BVIP to access the contents of a Metaplan card, a team member in the brainstorming meeting is referring to by pointing. The prototype of our system shows that targets on the screen a user is pointing at can be detected with 80% accuracy.

Abstract In recent years, assistive technology and digital accessibility for blind and visually impaired people (BVIP) has been significantly improved. Yet, group discussions, especially in a business context, are still challenging as non-verbal communication (NVC) is often depicted on digital whiteboards, including deictic gestures paired with visual artifacts. However, as NVC heavily relies on the visual perception, whichrepresents a large amount of detail, an adaptive approach is required that identifies the most relevant information for BVIP. Additionally, visual artifacts usually rely on spatial properties such as position, orientation, and dimensions to convey essential information such as hierarchy, cohesion, and importance that is often not accessible to the BVIP. In this paper, we investigate the requirements of BVIP during brainstorming sessions and, based on our findings, provide an accessible multimodal tool that uses non-verbal and spatial cues as an additional layer of information. Further, we contribute by presenting a set of input and output modalities that encode and decode information with respect to the individual demands of BVIP and the requirements of different use cases.

To allow users to perform real walking in a virtual environment larger than the physical space, redirected walking (RDW) techniques could be employed. Users do not notice this manipulation and immersion remains intact when RDW is applied within certain thresholds. Although many studies on RDW detection thresholds exists, in none of these studies, users were performing an additional task during the threshold identification process. These existing thresholds could be only conservative estimates and the potential of RDW may not be fully utilized.

Redirected Walking (RDW) allows users to perform real walking in virtual worlds that are larger than the available physical space. Many RDW algorithms rely on the prediction of users’ possible paths in the virtual environment (VE) to calculate where users should be redirected to. This prediction could be obtained from the structure of the VE, where users look, or from existing path models. In this work, we examine users’ walking behaviors in the presence of a virtual agent acting as a tour guide. Results showed that users changed their speed significantly to match the agent’s walking speed. Furthermore, users also tend to adapt their trajectories to match with the agent’s path.

Hand gesture recognition is a strenuous task to solve in videos. In this paper, we use a 3D residual attention network which is trained end to end for hand gesture recognition. Based on the stacked multiple attention blocks, we build a 3D network which generates different features at each attention block. Our 3D attention based residual network (Res3ATN) can be build and extended to very deep layers. Using this network, an extensive analysis is performed on other 3D networks based on three publicly available datasets. The Res3ATN network performance is compared to C3D, ResNet-10, and ResNext-101 networks. We also study and evaluate our baseline network with different number of attention blocks. The comparison shows that the 3D residual attention network with 3 attention blocks is robust in attention learning and is able to classify the gestures with a better accuracy, thus outperforming existing networks.

While facilitated brainstorming is a proven ideation method for professional teams, distributed teams are currently not able to enjoy its benefits. As workers are shifting towards collaborating in distributed settings, understanding how interactive systems can support facilitated brainstorming is becoming necessary to ensure that distributed teams remain creative. To address this challenge we designed, implemented, and evaluated DigiMetaplan---an interactive surface-based system for distributed facilitated brainstorming for co-located and remote users. The design of DigiMetaplan was inspired by a widely-used facilitated brainstorming method called Metaplan, where the brainstorming process of a group is coordinated by a facilitator. We evaluated the usability of DigiMetaplan with five hybrid teams consisting of a co-located facilitator and two team members connected with one remote participant. Results showed that the features used in DigiMetaplan on interactive surfaces effectively supported teams in performing facilitated collaborative brainstorming in partially distributed settings. We contribute knowledge on how a brainstorming environment translated into a multi-surface distributed system affects facilitated collaboration.

In predictive redirected walking applications, planning the redirection and path prediction are crucial for a safe and effective redirection. Common predictive redirection algorithms require many simplifications and limitations concerning the real and the virtual environments to achieve a real-time performance. These limitations include for example that the tracking space needs to be convex, and only a single user is supported. In this paper, we present a novel approach called PReWAP which addresses many of these shortcomings. We introduce artificial potential fields to represent the real environment which are able to handle non-convex environments and multiple co-located users. Further, we show how this new approach can be integrated into a model predictive controller which will allow various redirection techniques and multiple gains to be applied.

In predictive redirected walking applications, reliable path prediction is essential for an effective redirection. So far, most predictive redirected walking algorithms introduced many restrictions to the virtual environment in order to simplify this path prediction. Path prediction is time-consuming and is also prone to errors due to potentially impulsive and even irrational walking behaviour of humans in virtual environments. Therefore, many applications confine users in narrow virtual corridors or mazes in order to minimise larger deviations from intended and predictable walking patterns. In this paper, we present a novel approach for short-term path prediction which can be applied to virtual open space predictive redirected walking. We introduce a drop-shaped trajectory prediction which is described using a Lemniscate of Bernoulli. The drop's contour is discretised and we show how this is used to determine potential user trajectories in the virtual environment.

To enable real walking in a virtual environment (VE) that is larger than the available physical space, redirection techniques that introduce multisensory conflicts between visual and nonvisual cues to manipulate different aspects of a user's trajectory could be applied. When applied within certain thresholds, these manipulations could go unnoticed and immersion remains intact. Research effort has been spent on identifying these thresholds and a wide range of thresholds was reported in different studies. These differences in thresholds could be explained by many factors such as individual differences, walking speed, or context settings such as environment design, cognitive load, distractors, etc.

For comprehensively participating in society, independent and safe mobility is an important skill for many daily activities. Spatial cognition is one of the most important human capabilities and addresses the acquisition, processing and utilization of knowledge about the spatial layout of environments. Humans predominantly use the visual sense for this and for blind and low vision people, the lack of spatial perception reduces their quality of life and their ability of independent living. In particular the spatial navigation in unknown environments imposes challenges, since there is no possibility to train navigation tasks in advance. Today, blind and visually impaired people still rely on traditional navigation aids such as a cane for micro-navigation, which - however - does not help for developing orientation at larger scale or for planning of routes. To overcome this problem, this paper introduces the concept of a virtual environment that allows experiencing unknown locations by real walking while still staying in a sage controlled environment. Since this virtual environment can be controlled in its complexity, it can be adjusted from an abstract training scenario to a real-life situation such as train stations or airports.

Redirected walking applications allow a user to explore large virtual environments in a smaller physical space by employing so-called redirection techniques. To further improve the immersion of a virtual experience, path planner algorithms were developed which choose redirection techniques based on the current position and orientation of the user. In order to ensure a reliable performance, planning algorithms depend on accurate position tracking using an external tracking system. However, the disadvantage of such a tracking method is the time-consuming preparation of the physical environment which renders the system immobile. A possible solution to eliminate this dependency is to replace the external tracking system with a state-of-the-art inside-out tracker based on the concept of Simultaneous Localization and Mapping (SLAM). In this paper, we present an approach in which we attach a commercially available SLAM device to a head-mounted display to track the head motion of a user. From sensor recordings of the device, we construct a map of the surrounding environment for future processing in an existing path planner for redirected walking.

Redirected walking (RDW) refers to a number of techniques that enable users to explore a virtual environment larger than the real physical space. These techniques are based on the introduction of a mismatch in rotation, translation and curvature between the virtual and real trajectories, quantified as rotational, translational and curvature gains. When these gains are applied within certain thresholds, the manipulation is unnoticeable and immersion is maintained. Existing studies on RDW thresholds reported a wide range of threshold values. These differences could be attributed to many factors such as individual differences, walking speed, or environment settings. In this paper, we propose a study to investigate one of the environment settings that could potentially influence curvature RDW thresholds: the environment size. The detailed description of the study is also provided, where the adaptive, 2-alternative forced choice method is used to identify the detection thresholds.

Moving through a virtual environment (VE) by real walking is beneficial to user immersion, feeling of presence and way finding. However, the available physical spaces are of limited size and usually much smaller than the VE. One solution to this problem is using redirection techniques (RDTs). While the focus of existing research has been mostly on continuous RDTs, work on discrete RDTs is still limited.

Existing redirected walking applications use accurate tracking systems to determine the position and orientation of the user within a designated tracking space. In order to plan redirection and to ensure the user's safety, it is necessary to define the walking area in advance. However, when using ad hoc redirected walking, this is not possible, because the user's surroundings are not known beforehand.

While videoconferencing has been available for years, tools for distributed creative collaboration such as brainstorming have not yet reached professional use. Unlike regular conferencing, brainstorming relies on information exchange across multiple channels in shared task and communication spaces. If a participant joins a facilitated brainstorming session remotely through his/her mobile device, perceiving these spaces is challenging. By proposing an immersive environment for the remote participant, this tech note addresses how to provide him/her a stronger engagement. Offered as a client application for the remote participant's tablet device, it enables him/her to see all channels and select which one to interact with. Our proof-of-concept client allows us to examine how this immersive environment for distributed creative collaboration can provide the remote participant with an increased engagement.

Redirected Walking Techniques (RWTs) enable a user to immersively explore a virtual environment larger than the available physical space by real walking. RWTs are based on the use of gains (translational, rotational and curvature), which introduce a mismatch between the virtual and physical trajectories. When these gains are applied within certain thresholds, the "manipulation" is unnoticeable and immersion is maintained. Numerous research has been carried out to identify these thresholds and factors that affect them such as walking speed, environment structure or tasks involved. However, it has not been known whether users change their walking behavior when RWTs are applied and if this in turn influences ftheir perception thresholds.

Redirected walking refers to a number of techniques that enable users to explore a virtual environment larger than the physical space by real walking. The efficiency of these techniques has been shown to improve when predictions about the user's future trajectory are incorporated. Predictions can be made not only based on the knowledge about the environment but also on how humans behave in it. In a maze-like environment, it is known that most animal species show a strong preference to alternate their turning direction. This is called spontaneous alternation behavior (SAB). Although such behavior has also been observed in humans during maze tracing tasks, little is known whether they also exhibit this behavior during real walking, and if they do, what their alternation rate is.

Providing real walking in virtual environments remains a challenge because of space, setup, and tracking system requirements. With the help of redirected walking (RDW), natural and unconstrained walking in virtual environments has become possible - without using mechanical locomotion devices - by manipulating the user's real world trajectory such that he remains within the boundaries of the walkable space. Nevertheless, typical home or office environments do not provide sufficient space or a suitable room which is free of obstacles. This paper presents an approach that combines RDW with a low-cost and user-worn tracking approach based on simultaneous localization and mapping (SLAM). I.e. learning the environment with the walkable area, tracking the user's viewpoint, and RDW is done on the fly without any prior setup, without preparing a room, and without setting up a tracking system. This allows ad hoc free walking in virtual environments even within dynamic and cluttered physical rooms, where the walkable area is of arbitrary shape. Furthermore, by combining SLAM and a planning RDW controller, this approach has the potential to provide the best free walking experience for any given physical environment.

Microsoft Kinect is widely used for tracking human body in a range of applications. Although Kinect for Xbox One allows for multi-user tracking, it is not possible to use it in large spaces due to its limited range. Hence, using multiple Kinect sensors for large environments seems to be an appropriate solution. Thus, it is important to know if multiple sensors can be used simultaneously for such applications without interfering with each other. In this paper, we investigate the effect of using multiple Kinects on each other by performing multiple measurements in different settings. Our results show that some occasional interference might happen in some specific constellations, when the sensors are facing the same target. Our recommendation is to avoid such constellations, or to perform a simple interference measurement before using multiple sensors in specific settings.

Redirected walking (RDW) allows users to interact with a Virtual Environment (VE) much larger than the real space. However, there is a limit to how much a user can be redirected such that immersion in the VE is still preserved. While much effort has been spent on identifying this limit, so-called redirected walking thresholds, these thresholds are more a general guideline than being personalized for each user. Since individuals' differences in perception play an important role in users's experience in a redirected VE, there is potential to optimize the thresholds using these differences.

Postural stability is an important measure for many medical diseases such as Parkinson. In the last years, research focused on using inexpensive and portable devices to measure postural stability, while the visual targets were physical objects in the environment. Sensing balancing boards were used to measure stance forces, while movements of the upper body were not taken into account. Within this paper, postural stability was measured using the HTC Vive. A variation of a virtual fixation point's distance was analyzed and compared to a reference condition with closed eyes. It is shown that body sway in the VR conditions is increased in the anterior-posterior and decreased in the medial-lateral direction.

Redirected Walking allows a person to explore unlimited virtual environments in a limited physical tracking space. To prevent the user from colliding with the physical boundaries of the tracking space, so-called redirection techniques are used. These techniques introduce a subtle mismatch between the user's real and virtual movement and therefore keep him inside the tracking space while at the same time they allow him to explore an unlimited virtual environment. In most cases, there is more than one redirection technique available, and steering algorithms are used to select the best one at any given time. These algorithms use an optimal control scheme to select the optimal redirection action based on a prediction of the user's future path. In this paper, we present a novel approach for predicting a person's locomotion target. Using a set of known possible targets and models of human locomotion, this approach creates a set of expected paths and compares them to the path already traveled by the user in order to estimate the probability of the user heading for a certain target. We present a new approach for comparing two paths and evaluate its performance against three other approaches. We also compare four different ways of modeling a human's path to a target. To gather data for the comparison, a user study is conducted and the prediction performance of the different proposed approaches is discussed.

Tracking human movements and locomotion accurately in real time - e.g. for providing real walking in virtual environments - requires expensive tracking systems which need a lot of time to install. Furthermore, the costs typically increase with the size of the tracked space as these systems rely on external references. This poster presents an approach to significantly reduce costs for tracking human locomotion in large, potentially unlimited tracking spaces. The proposed approach employs a low-cost user-worn position and orientation tracking system to track the position and orientation of limbs including the user's feet. To associate the relative limbs' movement within the user's local coordinate system with the absolute movement in a given environment, the feet stance phase is used. Whenever a foot enters the stance phase, the local position is locked onto the global position because the foot is not moving. This allows tracking a person with all locally tracked objects - e.g. limbs, head, etc. - by temporarily locking the absolute position alternately to the user's feet in a step by step manner. This tracking works continuously and in real time without any external references.

Abstract When navigating in virtual environments by using real walking, the correct auditory step feedback is usually ignored, although this could give more information to the user about the ground he is walking on. One reason for this is time constraints that hinder a replay of a walking sound synchronous to the haptic step feedback when walking. In order to add a matching step feedback to virtual environments, this paper introduces a calibration‐free system, which can predict the occurrence time of a step‐down event based on an analysis of the user's gait. For detecting reliable characteristics of the gait, accelerometers and gyroscopes are used, which are mounted on the user's foot. Because the proposed system is capable of detecting the characteristic events in the foot's swing phase, it allows a prediction that gives enough time to replay sound synchronous to the haptic sensation of walking. In order to find the best prediction regarding prediction time and accuracy, data gathered in an experiment is analyzed regarding reliably occurring characteristics in the human gait. Based on this, a suitable prediction algorithm is proposed. Copyright © 2014 John Wiley & Sons, Ltd.

This paper presents a novel approach to estimate a person's intended locomotion target. This estimation is based on models of human locomotion and the finding that locomotion is planned such that the movement minimizes a certain cost function. Using such a cost function, we calculate the expected costs for a path trajectory to a number of possible targets, and make an estimation of a person's intended target based on changes in these expected costs in relation to the cost of the path up to this point.

Virtual reality systems supporting real walking as a navigation interface usually lack auditory step feedback, although this could give additional information to the user e.g. about the ground he is walking on. In order to add matching auditory step feedback to virtual environments, we propose a calibration-free and easy to use system that can predict the occurrence time of stepping sounds based on human gait data.

Digital collaborative environments enable spatially separated users to access and modify shared data over network. However, transmission delays of the network lead to inconsistent data and reduce the efficiency of collaboration due to interaction conflicts. In this paper, we present a predictive screen-locking algorithm to avoid interaction collisions on net-based shared interactive screens. A model-based predictor calculates the user's next interaction given his past one. The algorithms locks critical objects to the remote station which is less likely to interact with the object. Although the predictor continuously adapts to the user's interaction behavior, an initial interaction model is needed when the collaboration session is started. Hence, we deduce a reasonable, probabilistic interaction model from a large screen collaboration user study.

When human locomotion is used to interact with virtual or augmented environments, the system's immersion could be improved by providing reliable information about the user's walking intention. Such a prediction can be derived from tracking data to determine the future walking direction. This paper analyses how tracking data relates to navigation decisions from an egocentric view in order to achieve a reliable and stable path prediction. Since tracking data is noisy, a smoothening is required that eliminates oscillations while still recognizing trends in human locomotion. Thus, we analyze different approaches for path prediction, determine relevant setting values, and verify the results by a user study. Results indicate that robust short term prediction of human locomotion is possible but care must be taken when designing such a predictor.

An increasing number of human computer interaction systems are employing interactive table surfaces. For these horizontally aligned screens, the orientation of text passages and any other 'oriented' graphical content is a common problem. A user will not be able to easily read the same text from different sides of such a table unless it adapts to his position. To overcome this problem, we present an interactive system that extends the interaction space from measuring the direct manipulation on the interaction plane to observing the user in the space above the table. Hence, the content of the graphical user interface can automatically be aligned to the position of the active user, which enables the ergonomic reading of a text. We present a viewpoint tracking system, which utilizes the Microsoft Kinect depth sensor accessed with the OpenNI framework. This system does not need initial pose calibration and smoothens the vision based tracking data. In a next step, we show the benefit of extending the interaction space for a drawing application that allows multiple users to work on automatically oriented, digital notepads while still being able to freely move around the table.

Motion platforms are advanced systems for driving simulators. Studies showed that these systems imitate the real driving behavior of cars very accurately. In low-cost driving simulators, most installations lack motion platforms and miss to simulate real motion forces. Their focus is on high-quality video and audio, or force feedback on steering wheels. We aim to substitute the real motion forces with low-cost actuators triggering the human extremities to create an extended immersion. By this, the quality of driving simulators without any motion platform can be increased. Our full body haptic display concept for low-cost racing car simulators is based on air cushion and pull mechanisms to support longitudinal and lateral forces addressing the human's mechanoreceptive and proprioceptive senses. The concept is analyzed within a user study covering twenty-two participants.

In this paper, we present a device called `CollaBoard'. It was developed in the context of ongoing CSCW research efforts in developing groupware that mediates remote collaboration processes. CollaBoard combines video- and data-conferencing by overlaying a life-sized video showing the entire upper body of remote people in front of the displayed shared content. By doing so, CollaBoard shows pose, gaze, and gestures of remote partners, preserves the meaning of users' deictic gestures when pointing at displayed shared artifacts, and keeps shared artifacts editable at both conference sites. For this, a new whiteboard software is also introduced, which allows a real-time synchronization of the generated artifacts. Finally, the functionality of two interconnected CollaBoard prototypes was verified in a usability assessment.

On interactive surfaces, a precise calibration of the tracking system is necessary for an exact user interaction. So far, common calibration techniques focus on eliminating geometric distortions. This static calibration is only correct for a specific viewpoint of one single user and parallax error distortions still occur if this changes (i.e. if the user moves in front of the digital screen). In order to overcome this problem, we present an empirical model of the user's position and movement in front of a digital screen. With this, a model predictive controller is able to correct the parallax error for future positions of the user. We deduce the model's parameters from a user study on a large interactive whiteboard, in which we measured the 3D position of the user's viewpoint during common interaction tasks.

In this paper we present a mixed presence groupware device called "CollaBoard". The device improves collaboration between co-located and remote partners by providing a high level of workspace awareness. This is achieved by superimposing a life-size video showing the entire upper body of remote collaborators atop the displayed shared workspace. By doing so, the CollaBoard enriches the shared workspace with embodiments of remote collaborators. It shows pose, gaze and gestures of collaborators to their remote partners, and preserves the meaning of deictic gestures when pointing at displayed shared artifacts. The separate transmission of video and data allows the shared artifacts to remain editable at both conference sites. The functionality of two interconnected CollaBoard prototypes was verified in a public demonstration, a usability test, and a comparative user study.

In this paper, we suggest a new way to add multi-touch capabilities to an LC-screen. For this, FTIR and IR-sensing behind the LC-screen will be combined. Using a large infrared sensor array mounted behind the LC-matrix, infrared light in front of the screen, which is strong enough to pass through the LC-screen's components, can be detected The FTIR-technology is able to deliver such infrared light to the integrated sensors when touching the screen with the fingers. For the prototype, the key parameters of the FTIR principle were experimentally analyzed to optimize the sensor reactivity. The 4x8 sensor prototype can simultaneously detect multiple touches with an accuracy of around 1 mm and with an update rate of 200 Hz.

In this paper, we present a new technology to perform multi Tangible User Interface (TUI) tracking on standard LC-displays. A lot of existing technologies for tangible user interface tracking use back- or front-projection setups, but they suffer from poor image quality, shadow casting, non-ergonomic interaction, and/or large installations. Thus, we introduce a principle that allows using the InfrActables' technology on a large LC-display. It combines simultaneous multiuser input on a display with the advantages of a large flat screen. We use infrared photodiodes (IR-LEDs) mounted behind the display's LC-matrix to track infrared diodes in front of the screen. After initial tests concerning the infrared transparency and sensor characteristics, we developed a proof of concept consisting of 384 sensors, which are addressed through a modular master-slave circuit. Using several interaction devices, multiuser interaction is possible.

We present InfrActables, a wireless technology for human computer interaction devices. It allows multiple users to interact simultaneously on back-projection displays. It recognizes each device’s position, orientation, and identification, but also enables the tools to communicate their states to the application that the user interacts with. This makes it possible to build complex interaction devices for direct manipulation with buttons, sliders, and other input capabilities. The technology was developed for a computer-supported environment, allowing multiple users to interact simultaneously on a surface using multiple styli and other user input devices. The principle of operation is not limited to two-dimensional surfaces, three-dimensional user input devices can also profit from its advantages.

Complex business processes and globally distributed teams require new means to support net-based teamwork. Here, virtual reality technologies offer new ways to a more intuitive collaboration. In this paper, a system setup dubbed HoloPort is presented, which enables intuitive point-to-point video conferencing between two small groups. The device features gaze awareness between local and remote conferees during video and data conferences, and pen-based on-screen interaction. After an introduction to tele-collaboration systems, the working principle of the proposed HoloPort is illustrated, and the device’s individual components are described in detail. Then, different application scenarios using the HoloPort are discussed. Finally, the paper concludes with an outlook on future improvements.

The so-called "blue-c" is a novel three sided immersive projection system, which has been especially designed to support telecollaborative teamwork [4].Therefore, special projection screens are used, which can be switched to a transparent state electrically.The user is captured with sixteen cameras in total, standing outside of the projection room.These images are then processed to create a 3D representation of the user, which can be projected in a second installation.The whole installation has been engineered and implemented at the ETH Zurich [9].A special active stereo projection system, based on LCD projectors with additional shutters proved to work very well at a very competing price.The paper describes the background of the decisions made and the problems that had to be overcome.

This paper introduces a preliminary study about the Smart-Mesh, a novel type of active structure capable of deforming actively its shape and thus being able to form objects. It is a new approach to find a solution to the difficulties that are encountered in the field of haptic interaction in virtual environments. The paper describes the basic working principles of the structure, which allow the generation of overhanging surfaces. A first prototype based on 16 nodes and 48 linkages with prismatic joints is presented. The SmartMesh can be embedded into a table, into walls, ceilings and floors. The resolution of the SmartMesh depends on the amount of nodes and the length of the linkages. The linkages can be replaced by linear actuators.

After a wrap-up in the human physiology and an overview on physical principles, this paper introduces four novel types of actuators for haptic feedback devices based on electroactive polymers, which were developed and evaluated for their suitability for haptic feedback devices. The electroactive polymers show many promising properties, such as big expansion, high frequency range and big force exertion for instance. Unfortunately they are still in the fledgling state and are not available on the market yet. The actuators presented in this paper are a contribution to the haptic and to the electro active polymer researchers community.

We present blue-c , a new immersive projection and 3D video acquisition environment for virtual design and collaboration. It combines simultaneous acquisition of multiple live video streams with advanced 3D projection technology in a CAVE™-like environment, creating the impression of total immersion. The blue-c portal currently consists of three rectangular projection screens that are built from glass panels containing liquid crystal layers. These screens can be switched from a whitish opaque state (for projection) to a transparent state (for acquisition), which allows the video cameras to "look through" the walls. Our projection technology is based on active stereo using two LCD projectors per screen. The projectors are synchronously shuttered along with the screens, the stereo glasses, active illumination devices, and the acquisition hardware. From multiple video streams, we compute a 3D video representation of the user in real time. The resulting video inlays are integrated into a networked virtual environment. Our design is highly scalable, enabling blue-c to connect to portals with less sophisticated hardware.

Virtual Reality allows a simultaneous representation of three dimensional objects in different interconnected visualization installations. This offers new possibilities for distributed collaborative work. Up to now the user remained mostly without consideration. But for an efficient distributed collaborative teamwork the user should be visualized three dimensionally together with other virtual objects. A special projection installation is presented which allows simultaneous projection as well as picture acquisition of the person who uses the installation.

Virtual reality (VR) can be extended to create a collaborative distributed environment over a physical network. However, such an environment can only be established if both the virtual objects and the other users can be seen simultaneously in real time. This requires a novel technique to overcome the contradicting requirements of darkness and light for image projection and video acquisition, respectively. In order to make an inexpensive and easy-to-build solution, a camera acquisition system and a stroboscopic light are added to an existing VR system. Modifications are made to existing shutter glasses to handle simultaneous projection and video acquisition. In such a solution, the method of projection in the VR system remains unmodified. This paper describes how to resolve the conflict between the darkness required for projection and sufficient lighting for video acquisition.