Relative and Absolute Mappings for Rotating Remote 3D Objects on Multi-Touch Tabletops

The use of human fingers as an object selection and manipulation tool has raised significant challenges when interacting with direct-touch tabletop displays. This is particularly an issue when manipulating remote objects in 3D environments as finger presses can obscure objects at a distance that are rendered very small. Techniques to support remote manipulation either provide absolute mappings between finger presses and object transformation or rely on tools that support relative mappings t o selected objects. This paper explores techniques to manipulate remote 3D objects on direct-touch tabletops using absolute and relative mapping modes. A user study was conducted to compare absolute and relative mappings in support of a rotation task. Overall results did not show a statistically significant difference between these two mapping modes on both task completion time and the number of touches. However, the absolute mapping mode was found to be less efficient than the relative mapping mode when rotating a small object. Also participants preferred relative mapping for small objects. Four mapping techniques were then compared for perceived ease of use and learnability. Touchpad, voodoo doll and telescope techniques were found to be comparable for manipulating remote objects in a 3D scene. A flying camera technique was considered too complex and required increased effort by participants. Participants preferred an absolute mapping technique augmented to support small object manipulation, e.g. the voodoo doll technique

Exploring Dual-Camera-Based Augmented Reality for Cultural Heritage Sites

Context: Augmented Reality (AR) provides a novel approach for presenting cultural heritage content. Recent advances in AR research and the uptake of powerful mobile devices means AR is a viable option for heritage institutions, but there are challenges that must be overcome before high-quality AR is commonplace. Aims: This project details the development of an AR “magic camera” system featuring novel dual-camera marker-based tracking, allowing users to take AR photos at outdoor heritage sites using a tablet computer. The aims of the project were to assess the feasibility of the tracking method, evaluate the usability of the AR system, and explore implications for the heritage sector. Method: A prototype system was developed. A user study was designed, where participants had to recreate reference images as closely as possible using an iPad and the AR system around the University grounds. Data, such as completion time and error rates, were collected for analysis. The images produced were rated for quality by three experts. Results: Participants responded positively to the system, and the new tracking method was used successfully. The usability study uncovered a number of issues, most of which are solvable in future software versions. However, some issues, such as difficulty orientating objects, rely on improving hardware and software before they can be fixed, but these problems did not affect the quality of the images produced. Participants completed each task more quickly after initial slowness, and while the system was frustrating for some, most found the experience enjoyable. Conclusion: The study successfully uncovered usability problems. The dual-camera tracking element was successful, but the marker-based element encountered lighting problems and high false-positive rates. Orientating objects using inertial sensors was not intuitive; more research in this area would be beneficial. The heritage sector must consider development, maintenance and training costs, and site modification issues