127 research outputs found
CONTENTS Textures that Fool
No full textMy project is called Textures that Fool, which is an investigation into the use of impostering. It was produced by myself, Alex Sawczuk during April 2007, with the assistance of my tutor Roger Hubbold The general purpose of my project was to see if there is any noticeable loss of image quality when using a technique called Impostering. Impostering is a form of level of detail [A9], which replaces the original geometry by a much simplified version of the original. Impostering in particular makes gains by using a very simple geometric model, and texturing this by rendering the original object in real time, and saving this texture and mapping it to the imposter. The key aims of my project are to see if there are any graphical differences between a scene using imposterin
Amplifying head movements with head-mounted displays
No full textThe head-mounted display (HMD) is a popular form of virtual display due to its ability to immerse users visually in virtual environments (VEs). Unfortunately, the user's virtual experience is compromised by the narrow field of view (FOV) it affords, which is less than half that of normal human vision. This paper explores a solution to some of the problems caused by the narrow FOV by amplifying the head movement made by the user when wearing an HMD, so that the view direction changes by a greater amount in the virtual world than it does in the real world Tests conducted on the technique show a significant improvement in performance on a visual search task, and questionnaire data indicate that the altered visual parameters that the user receives may be preferable to those in the baseline condition in which amplification of movement was not implemented. The tests also show that the user cannot interact normally with the VE if corresponding body movements are not amplified to the same degree as head movements, which may limit the implementation's versatility. Although not suitable for every application, the technique shows promise, and alterations to aspects of the implementation could extend its use in the future
A Multi Modal Table-Top 3D Modeling Tool in Augmented Environments
No full textEven with today's highly sophisticated 3D modeling programs, creating, assembling and adapting 3D models is still a big challenge for inexperienced users. In this paper we present our approach of an intuitive table-top 3D modeling tool in Augmented Reality. It allows the author to view 3D virtual objects within his natural working environment, to manipulate them and to create new 3D elements easily. The offered interaction techniques support the author's activity by a combination of tangible user interfaces with voice recognition, a gaze-based view pointer and 3D widgets as components of a multi modal user interface. Within the scope of this work, intuitive interaction techniques were realized to offer the participants an easy way of working within an augmented environment. User tests were performed to compare our approach to a WIMP-based desktop application and to an alternative AR modeling application.Eurographics Symposium on Virtual Environment
Managing Missed Interactions in Distributed Virtual Environments
No full textA scalable distributed virtual environment (DVE) may be achieved by ensuring virtual world objects communicate their actions to only those objects that fall within their influence, reducing the need to send and process unnecessary messages. A missed interaction may be defined as a failure to exchange messages to appropriately model object interaction. A number of parameters under the control of a DVE developer may influence the possibility of missed interactions occurring (e.g., object velocities, area of influence). However, due to the complexities associated with object movement and the deployment environment (e.g., non-deterministic object movement, network latency), identifying the value for such parameters to minimise missed interactions while maintaining scalability (minimal message passing) is not clear. We present in this paper a tool which simulates a DVE and provides developers with an indication of the appropriate values for parameters when balancing missed interactions against scalability.Eurographics Symposium on Virtual Environment
A New View Management Method for Wearable Augmented Reality Systems - Emphasizing the User-viewed Object and the Corresponding Annotation -
No full textThis paper describes a new view management method for annotation overlay using augmented reality(AR) systems. The proposed method emphasizes the user-viewed object and the corresponding annotation in order to present links between annotations and real objects clearly. This method includes two kinds of techniques for emphasizing the user-viewed object and the annotation. First, the proposed method highlights the object which is gazed at by the user using a 3D model without textures. Secondly, when the user-viewed object is occluded by other objects, the object is complemented by using an image made from a detailed 3D model with textures. This paper also describes experiments which show the feasibility of the proposed method by using a prototype wearable AR system.Eurographics Symposium on Virtual Environment
GraphTracker: A Topology Projection Invariant Optical Tracker
No full textIn this paper, we describe a new optical tracking algorithm for pose estimation of interaction devices in virtual and augmented reality. Given a 3D model of the interaction device and a number of camera images, the primary difficulty in pose reconstruction is to find the correspondence between 2D image points and 3D model points. Most previous methods solved this problem by the use of stereo correspondence. Once the correspondence problem has been solved, the pose can be estimated by determining the transformation between the 3D point cloud and the model. Our approach is based on the projective invariant topology of graph structures. The topology of a graph structure does not change under projection: in this way we solve the point correspondence problem by a subgraph matching algorithm between the detected 2D image graph and the model graph. There are four advantages to our method. First, the correspondence problem is solved entirely in 2D and therefore no stereo correspondence is needed. Consequently, we can use any number of cameras, including a single camera. Secondly, as opposed to stereo methods, we do not need to detect the same model point in two different cameras, and therefore our method is much more robust against occlusion. Thirdly, the subgraph matching algorithm can still detect a match even when parts of the graph are occluded, for example by the users hands. This also provides more robustness against occlusion. Finally, the error made in the pose estimation is significantly reduced as the amount of cameras is increased.Eurographics Symposium on Virtual Environment
Measuring the Discernability of Virtual Objects in Conventional and Stylized Augmented Reality
No full textIn augmented reality, virtual graphical objects are overlaid over the real environment of the observer. Conventional augmented reality systems normally use standard real-time rendering methods for generating the graphical representations of virtual objects. These renderings contain the typical artifacts of computer generated graphics, e.g., aliasing caused by the rasterization process and unrealistic, manually configured illumination models. Due to these artifacts, virtual objects look artifical and can easily be distinguished from the real environment. A different approach to generating augmented reality images is the basis of stylized augmented reality [FBS05c]. Here, similar types of artistic or illustrative stylization are applied to the virtual objects and the camera image of the real enviroment. Therefore, real and virtual image elements look significantly more similar and are less distinguishable from each other. In this paper, we present the results of a psychophysical study on the effectiveness of stylized augmented reality. In this study, a number of participants were asked to decide whether objects shown in images of augmented reality scenes are virtual or real. Conventionally rendered as well as stylized augmented reality images and short video clips were presented to the participants. The correctness of the participants responses and their reaction times were recorded. The results of our study show that an equalized level of realism is achieved by using stylized augmented reality, i.e., that it is significantly more difficult to distinguish virtual objects from real objects.Eurographics Symposium on Virtual Environment
Hybrid Interfaces in VEs: Intent and Interaction
No full textHybrid user interfaces (UIs) integrate well-known 2D user interface elements into the 3D virtual environment, and provide a familiar and portable interface across a variety of VR systems. However, their usability is often reduced by accuracy and speed, caused by inaccuracies in tracking and a lack of constraints and feedback. To ease these difficulties often large widgets and bulky interface elements must be used, which, at the same time, limit the size of the 3D workspace and restrict the space where other supplemental 2D information can be displayed. In this paper, we present two developments addressing this problem: supportive user interaction and a new implementation of a hybrid interface. First, we describe a small set of tightly integrated 2D windows we developed with the goal of providing increased flexibility in the UI and reducing UI clutter. Next we present extensions to our supportive selection technique, IntenSelect. To better cope with a variety of VR and UI tasks, we extended the selection assistance technique to include direct selection, spring-based manipulation, and specialized snapping behavior. Finally, we relate how the effective integration of these two developments eases some of the UI restrictions and produces a more comfortable VR experience.Eurographics Symposium on Virtual Environment
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