Background
Large tiled wall displays allow users to explore large datasets and information visualisations. Using such display technologies has particular benefits in application areas such as health, security, retail and advertising etc. This research project was initialised by CSIRO with the support from the Australian National Data Service (ANDS) and the Australian Research Collaboration Services (ARCS). The goal of this project was to design and develop advanced interactions on large displays using tablet devices (e.g. iPads). I worked with another UI researcher at the ICT Centre in CSIRO on the successful delivery of this project.
Process
The standard research and design path was followed for this project, from initial brainstorming, detailed interaction design, rapid prototyping, user testing, results and feedback analysis, to the final system and reporting publication delivery.
Interaction design
After the initial consideration regarding possible applications, four interaction designs were proposed using tablet devices to interact with objects on large displays. Two of them were dual touch-based interaction techniques (named 'DualTaP' and 'DirectTaP'), and the other two were orientation-based techniques ('TabTilt' and 'TabPoint').
The four interaction designs: DualTaP (a), DirectTaP (b), TabTilt (c) and TabPoint (d).
DualTap: combines the pinch gesture and relative movements of two fingers, similar to the common single finger drag gesture for moving the mouse cursor with the trackpad, but with the capability of translating and scaling at the same time. As the distance between the two fingers increases, the size of the frame increases accordingly.
DirectTaP: is a variation to DualTaP but uses absolute positioning. It allows users to touch
directly on the miniature overview presented on the tablet with two fingers. The positions of these two fingers define the position and size of the frame, enabling the frame to jump instantly to the corresponding location, with the desired size. While still touching the screen, the frame can be readjusted.
TabTilt: uses the tilt angle of the tablet to change the position of the frame. Scaling is done using a pinch gesture on the touch device.
TabPoint: uses the direction of pointing of the tablet to determine the position of the frame on the large display. A pointing device (e.g. wiimote) is attached at the back of the tablet to accomplish such interaction. This technique can be thought of as an absolute version of TabTilt. Scaling is also done using the pinch gesture.
Usability testing
After building the functional prototypes for all four interaction designs, a formal usability test was conducted to evaluate their use in navigation on the large display. The test was designed to evaluate both user performance and subjective feedback on each design via a user task and a survery. The comparison of the testing results indicated the preference of using DualTaP over the other three designs.
The detailed designs and final testing outcomes as an article entitled 'Tablet Interaction Techniques for Viewport Navigation on Large Displays' has been published at the most prestigious international conference in human-computer interaction: the 2014 ACM Conference on Human Factors in Computing Systems (CHI-2014).
