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The language of geometric algebra can be used in the development of computer graphics applications. This paper proposes a method to describe a 3D polygonal mesh model using a representation technique based on geometric algebra and the conformal model of the 3D Euclidean space. It describes also the stages necessary to develop an application that uses this formalism. The current application was used to validate the implementation of the main abstract operations characteristic to a geometric algebra computational environment (programming module GAP). The data structures that characterize this geometric algebra based modeling approach as well as the implementation of geometric algebra based methods for model visualization/transformation are developed in detail. The paper emphasizes the elegance and generality of the geometric algebra approach referring also to the necessary computational resources.

In recent years, there has been an increasing amount of Collaborative Augmented Reality (CAR) experiences, classifiable by the deployed scale and the fidelity of the experience. In this paper, we create HoloRoyale, the first large scale high fidelity (LSHF) CAR experience. We do this by first exploring the LSHF CAR design space, drawing on technical implementations and design aspects from AR and video games. We then create and implement a software architecture that improves the accuracy of synchronized poses between multiple users. Finally, we apply our target experience and technical implementation to the explored design space. A core design component of HoloRoyale is the use of visual repellers as crowd control elements to guide players away from undesired areas. To evaluate the effectiveness of the employed visual repellers in a LSHF CAR context we conducted a user study, deploying HoloRoyale in a 12.500 m2 area. The results from the user study suggest that visual repellers are effective crowd control elements that do not significantly impact the user’s overall immersion. Overall our main contribution is the exploration of a design space, discussing several means to address the challenges of LSHF CAR, the creation of a system capable of LSHF CAR interactions along with an experience that has been fitted to the design space, and an indepth study that verifies a key design aspect for LSHF CAR. As such, our work is the first to explore the domain of LSHF CAR and provides insight into designing experiences in other AR domains.

In the field of augmented reality (AR), many kinds of vision-based extrinsic camera parameter estimation methods have been proposed to achieve geometric registration between real and virtual worlds. Previously, a feature landmark-based camera parameter estimation method was proposed. This is an effective method for implementing outdoor AR applications because a feature landmark database can be automatically constructed using the structure-from-motion (SfM) technique. However, the previous method cannot work in real time because it entails a high computational cost or matching landmarks in a database with image features in an input image. In addition, the accuracy of estimated camera parameters is insufficient for applications that need to overlay CG objects at a position close to the user's viewpoint. This is because it is difficult to compensate for visual pattern change of close landmarks when only the sparse depth information obtained by the SfM is available. In this paper, we achieve fast and accurate feature landmark-based camera parameter estimation by adopting the following approaches. First, the number of matching candidates is reduced to achieve fast camera parameter estimation by tentative camera parameter estimation and by assigning priorities to landmarks. Second, image templates of landmarks are adequately compensated for by considering the local 3-D structure of a landmark using the dense depth information obtained by a laser range sensor. To demonstrate the effectiveness of the proposed method, we developed some AR applications using the proposed method.

Virtual reality (VR) application creation is a comprehensive development process that requires a variety of skills: not only hardware and software knowledge but also aesthetic design and storytelling abilities. A groupwork-based project is a suitable approach for creating a VR application because the group members can utilize their full powers and knowledge of their special fields through collaboration. Students learn best when they are actively involved in a process, such as in group discussion and field work. Such groupwork projects are also effective in improving their collaboration skills. This paper introduces an educational framework for creating VR applications through groupwork, and highlights the advantages of this framework.