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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... more
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.
Research Interests:
Nowadays, buildings or production facilities are designed using specialized design software and building information modeling tools help to evaluate the resulting virtual mock-up. However, with current, primarily desktop based tools it is... more
Nowadays, buildings or production facilities are designed using specialized design software and building information modeling tools help to evaluate the resulting virtual mock-up. However, with current, primarily desktop based tools it is hard to evaluate human factors of such a design, for instance spatial constraints for workforces. This paper presents a new tool for factory planning and evaluation based on virtual reality that allows designers, planning experts, and workforces to walk naturally and freely within a virtual factory. Therefore, designs can be checked as if they were real before anything is built.
On interactive surfaces, an accurate calibration is crucial for a precise user interaction. Today, geometric distortions are eliminated by a static calibration. However, this calibration is specific to a user’s posture and parallax... more
On interactive surfaces, an accurate calibration is crucial for a precise user interaction. Today, geometric distortions are eliminated by a static calibration. However, this calibration is specific to a user’s posture and parallax distortions occur if this changes (i.e. when the user moves in front of the screen or multiple users take turns).
In this paper, we describe an approach to apply Partially Observable Markov Decision Processes (POMDPs) for automatic online re-calibration to cope with changing viewpoints, which are indicated by uncertain observations of the user’s interaction quality on the surface.
In this paper, we describe an approach to apply Partially Observable Markov Decision Processes (POMDPs) for automatic online re-calibration to cope with changing viewpoints, which are indicated by uncertain observations of the user’s interaction quality on the surface.
Research Interests:
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... more
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,
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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... more
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.
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This Special Thematic Session describes the elements of an IT system that allows for a better integration of blind people in a MindMap brainstorming session together with sighted users. Software components will be introduced that convert... more
This Special Thematic Session describes the elements of an IT system that allows for a better integration of blind people in a MindMap brainstorming session together with sighted users. Software components will be introduced that convert the parallel information visualization to a serialized information representation, which will then be output on a special blind user interface using screen reader and Braille display. Moreover, non-verbal communication elements are another important carrier of information, which also need to be captured and displayed to the blind user. Thus, this session also describes the necessary hardware components and the overall setup, which will allow for a more efficient teamwork in such a mixed team.
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A common problem in optical motion capture is the so-called missing marker problem. The occlusion of markers can lead to significant loss of tracking accuracy unless continuous data flow is guaranteed by computationally demanding... more
A common problem in optical motion capture is the so-called missing marker problem. The occlusion of markers can lead to significant loss of tracking accuracy unless continuous data flow is guaranteed by computationally demanding interpolation or extrapolation schemes. Since interpolation algorithms require data sampled before and after an occlusion, they cannot be used for real-time applications. Extrapolation algorithms only require data sampled before an occlusion. Other algorithms require statistical data and are designed for post-processing. In order to bridge sampling gaps caused by occluded markers and hence to improve 3D real-time motion capture, we suggest a real-time extrapolation algorithm. The realization of this prediction algorithm does not need statistical data or rely on an underlying cinematic human model with pre-defined marker distances. Under the assumption that natural motion can be linear, circular, or a linear combination of both, a prediction method is suggested and realized. The paper presents linear and circular movement measurements for use when a marker is briefly lost. The suggested extrapolation method seems to behave well for a reasonable number of frames, not exceeding 200 milliseconds.
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... more
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
Research Interests:
Research Interests:
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,... more
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.
Research Interests:
Haptic rendering is the process of computing and generating forces in response to user interactions with virtual objects. The interaction modality of haptic feedback gains more and more of importance for simulation tasks in virtual... more
Haptic rendering is the process of computing and generating forces in response to user interactions with virtual objects. The interaction modality of haptic feedback gains more and more of importance for simulation tasks in virtual environments. However there are only very few portable haptic interfaces, with which the user can experience in a natural way the sensation of force feedback. The scope of this paper is to present a new portable haptic interface using shape memory alloy wires as actuators. Shape memory alloys (SMA), and especially the nickel-titanium compositions, offer a number of engineering properties available in no other material. The ability to respond with significant force and motion to small changes in ambient temperature and the capability to convert heat energy into mechanical work provide the designer with a new array of possibilities. Beside some application specific characterization of the actuator material with respect to energy consumption and dynamic behavior for loading, the mechanical layout of the interface is discussed in detail. To realize a light and compact design of the interface, a flexure hinge is considered as an essential part of interface.
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In a collaborative environment, non-verbal communication elements carry important contents. These contents are partially or completely lost in remote collaboration. This paper presents a system to address this issue by tracking pointing... more
In a collaborative environment, non-verbal communication elements carry important contents. These contents are partially or completely lost in remote collaboration. This paper presents a system to address this issue by tracking pointing gestures, the main non-verbal communication element prevalent in such meetings. The setup employs a touchscreen tabletop computer system for representing the visual content of the meeting, together with three motion trackers for tracking the pointing gestures.
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Research Interests:
ABSTRACT Many interactive screens suffer from the incoherence between image plane and interaction plane. The resulting gap causes parallax errors that hinder a precise interaction with the system. For many reasons, this gap cannot be... more
ABSTRACT Many interactive screens suffer from the incoherence between image plane and interaction plane. The resulting gap causes parallax errors that hinder a precise interaction with the system. For many reasons, this gap cannot be physically reduced any further, while a software correction is still missing. Thus, this paper introduces an observation model for a continuous automatic recalibration controller of the touch sensitive surface. First, we show that the overall interaction error stems partly from the parallax error, which depends on the changing viewpoint of the user. Hence, a static calibration cannot overcome this error. Being not directly measurable, a continuously adapting correction controller sets the appropriate correction parameter based on updating the estimate of the user_s viewpoint from the history of his interaction errors. To estimate the user_s viewpoint in front of the screen based on the interaction error on the screen, we secondly investigate the correlation of the two domains from data of a user study, working on a large interactive screen with a significant gap between image plane and interaction plane. The correlation analysis shows significant differences in the interaction error stemming for different viewpoints, which allows the controller to infer the viewpoint. Finally, we model the results as a discrete observation model for the Partially Observable Markov Decision Processes (POMDP) correction controller.
On interactive surfaces, an accurate calibration is crucial for a precise user interaction. Today, geometric distortions are eliminated by a static calibration. However, this calibration is specific to a user’s posture and parallax... more
On interactive surfaces, an accurate calibration is crucial for a precise user interaction. Today, geometric distortions are eliminated by a static calibration. However, this calibration is specific to a user’s posture and parallax distortions occur if this changes (i.e. when the user moves in front of the screen or multiple users take turns).
In this paper, we describe an approach to apply Partially Observable Markov Decision Processes (POMDPs) for automatic online re-calibration to cope with changing viewpoints, which are indicated by uncertain observations of the user’s interaction quality on the surface.
In this paper, we describe an approach to apply Partially Observable Markov Decision Processes (POMDPs) for automatic online re-calibration to cope with changing viewpoints, which are indicated by uncertain observations of the user’s interaction quality on the surface.
Research Interests:
The technique of virtual reality has been developed so far that it isn’t a privilege of large industries anymore but also smaller enterprises can take advantage of it. In this case the main item is the Digital Product which is used for... more
The technique of virtual reality has been developed so far that it isn’t a privilege of large industries anymore but also smaller enterprises can take advantage of it. In this case the main item is the Digital Product which is used for visualization tasks. The scope of this paper is to demonstrate how the Digital Product and its visualization is used in different enterprise processes and which benefits arise from that.
Research Interests:
ABSTRACT This book provides a comprehensive and updated insight into dielectric elastomers; one of the most promising classes of polymer-based smart materials and technologies. This technology can be used in a very broad range of... more
ABSTRACT This book provides a comprehensive and updated insight into dielectric elastomers; one of the most promising classes of polymer-based smart materials and technologies. This technology can be used in a very broad range of applications, from robotics and automation to the biomedical field. The need for improved transducer performance has resulted in considerable efforts towards the development of devices relying on materials with intrinsic transduction properties. These materials, often termed as ?smart? or ?intelligent?, include improved piezoelectrics and magnetostrictive or shape-memory materials. Emerging electromechanical transduction technologies, based on so-called ElectroActive Polymers (EAP), have gained considerable attention. EAP offer the potential for performance exceeding other smart materials, while retaining the cost and versatility inherent to polymer materials. Within the EAP family, ?dielectric elastomers?, are of particular interest as they show good overall performance, simplicity of structure and robustness. Dielectric elastomer transducers are rapidly emerging as high-performance ?pseudo-muscular? actuators, useful for different kinds of tasks. Further, in addition to actuation, dielectric elastomers have also been shown to offer unique possibilities for improved generator and sensing devices. Dielectric elastomer transduction is enabling an enormous range of new applications that were precluded to any other EAP or smart-material technology until recently. This book provides a comprehensive and updated insight into dielectric elastomer transduction, covering all its fundamental aspects. The book deals with transduction principles, basic materials properties, design of efficient device architectures, material and device modelling, along with applications.
Page 1. SIGRAD 2011 Multi-State Device Tracking for Tangible Tabletops Ali Alavi1, Brice Clocher1, Allen Smith1, Andreas Kunz2, and Morten Fjeld1 ... 2.6. Acknowledgements We greatly thank Erik Tobin for improving the readability of this... more
Page 1. SIGRAD 2011 Multi-State Device Tracking for Tangible Tabletops Ali Alavi1, Brice Clocher1, Allen Smith1, Andreas Kunz2, and Morten Fjeld1 ... 2.6. Acknowledgements We greatly thank Erik Tobin for improving the readability of this text. ...
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Concurrent product and production design in conjunction with mass customisation is in the focus of the work presented in this paper. The novel Product and Production Configuration Method (PPCM) is embedded in two dimensions: the value... more
Concurrent product and production design in conjunction with mass customisation is in the focus of the work presented in this paper. The novel Product and Production Configuration Method (PPCM) is embedded in two dimensions: the value chain dimension and the cognitive dimension. The value chain dimension includes the synchronisation of product and production design considering all variants implied by the
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Research Interests:
Research Interests:
Research Interests:
This paper focuses on the development of novel actuators for a portable force feedback glove for, but not limited to, the simulation of open surgeries. A conceptual design of a chain-like actuator based on electroactive polymers is... more
This paper focuses on the development of novel actuators for a portable force feedback glove for, but not limited to, the simulation of open surgeries. A conceptual design of a chain-like actuator based on electroactive polymers is introduced. One actuator element of this chain was built in order to explore and optimize the actuator manufacturing process. Actuators manufactured with this stable process were characterized through isometric and isotonic measurements. The results show that dielectric elastomer actuators are promising for a portable force feedback device.