Static Voronoi-based target expansion technique for distant pointing

Abstract

Addressing the challenges of distant pointing, we present the feedforward static targeting assistance technique VTE: Voronoibased Target Expansion. VTE statically displays all the activation areas by dividing the total screen space into areas such that there is only one target inside each area, also called Voronoi tessellation. The key benefit of VTE is in providing the user with an imm before the pointing task even begins: VTE then provides static targeting assistance for both phases of a pointing task, the ballistic motion and the corrective phase. With the goal of making the environment visually uncluttered, we present a first user study to explore the visual parameters of VTE that affect the performance of the technique. In a second user study focusing on static versus dynamic assistance, we compare VTE with Bubble Ray, a dynamic Voronoi-based targeting assistance technique for distant pointing. Results show that VTE significantly outperforms the dynamic assistance technique and is preferred by users both for ray-casting pointing and relative pointing with a hand-controlled cursor.

Investigating Visual Feedforward for Target Expansion Techniques

“…the expanded targets). First the Voronoibased Target Expansion (VTE) technique [10] provides an explicit static feedforward mechanism by displaying the entire space partitioning (i.e. the Voronoi tessellation) before and during the pointing task (Figure 1-a).…”

“…The visual feedforward mechanism is key since it provides a visual aid to the user on the effective expanded targets prior to the execution or completion of the pointing task, enabling the user to take full advantage of the target expansion technique. Recent studies [10,16] confirm the key role that the feedforward mechanism plays in the performance of a target expansion technique.…”

“…Thus researchers have proposed many targeting assistance techniques [1,3,4,6,8,10,11,12,15,16,17,18] to optimize pointing. Pointing can be accurately modeled using Fitts' law [4,9,13].…”

“…An example of space decomposition is the Voronoi tessellation [3,7,8,10,11] that maximizes the use of empty space and is unambiguous since only one target is contained in each Voronoi cell. Several target expansion techniques implement a target expansion algorithm based on the Voronoi tessellation [3,6,8,10,11,15]: The expanded targets then correspond to the Voronoi cells and the user can point anywhere inside the target Voronoi cell instead of pointing at the target. For target expansion both in the motor and visual spaces, the design challenge of target expansion techniques is to make the motor target expansion visually observable through a feedforward mechanism.…”

“…Request permissions from Permissions@acm.org. We note that the experimental exploration of the design space is conducted in the context of distant pointing because: (1) Techniques enhancing target selection by expanding the targets demonstrated their efficiency in distant pointing for various contexts, including virtual 3D environments [18], large displays [17] and operating rooms [10]. (2) Our application domain is augmented surgery, where efficient distant pointing techniques are important when considering the cognitive workload of the surgeons.…”