Gaze-Based Moving Target Acquisition
using Pseudo Stopping for the Timepredicted via Fitts’ Law
Keita Shimasato, Yasuyuki Kono
Kwansei Gakuin University{k-Shimasato, kono}@kwansei.ac.jp

1. ABSTRACTThis paper describes a technique of gaze-based moving target
acquisition achieved by pseudo stopping the target for the time
predicted via Fitts’ Law, after saccades have been detected.
This technique only requires eye-movements for the acquisitionof moving targets. The results indicate that participants wereable to acquire targets moving at various speeds and withdifferent widths.

2. METHOD①detect saccade

A saccade is a quick eye
movement between two fixation.
In this technique, saccade
detection was achieved byemploying
thetechniqueproposed by Kumar et al [1].

3. EXPERIMENTS

The proposed technique was compared with the technique thatinvolves the acquisition of moving targets by gazing at thetargets for 400 ms. Eight subjects participated in this experiment.
We selected Tobii Eye Tracker 4C as the eye tracking device.
The participants were required to acquire all 96 types of moving
target (4 target width conditions 6 target velocities 4 target
movement patterns) with each technique once. In this task,
when the participants judge the target to be impossible toacquire, they can skip the pointing task of the target by pushinga particular key. We acquired each ratio of which all participants
skipped the task by judging the target to be impossible toacquire. (Table1, Table2)
Fix user’s head

60cm

②stop the target pseudo for the time predicted byFitts’ Low
After saccades have been
detected, the target is pseudostopped. The original moving
target is also displayed to makeit inconspicuous while the target
is stopped.

Tobii Eye Tracker 4C

Figure1. Experiment setup (left) and four types of moving target
which the participants require to acquire (right)
Table1. Skip rate for gazing at targets for 400ms③acquire the target
After users gaze at the stopped
target or the time predicted by
Fitts' Law has been passed, thetarget has been acquired. Then,we employing a dwell time
reduction technique proposedby Isomoto et al [2] because theuser must acquire the target
within the time predicted usingFitts’ Law.

Table2. Skip rate of proposed technique

4. CONCLUSION
Reference[1] Manu Kumar, Jeff. Klingner, Rohan. Puranik, Terry Winograd and Andreas Paepcke, 2008.
Improving the Accuracy of Gaze Input for Interaction, In Proceedings of the 2008 symposium on Eye
tracking research & application CHI Conference on Human Factors in Computing Systems (CHI’ 08), pp.
65- 68. https://doi.org/10.1145/1344471.1344488[2] Toshiya Isomoto, Toshiyuki Ando, Buntarou Shizuki and Shin Takahashi, 2018. Dwell Time
Reduction Technique using Fitts’ Law for Gaze-Based Target Acquisition, In Proceedings of the 2018
ACM Symposium on Eye Tracking Research & Application (ETRA’ 18, 2018), Article No26, pp. 1-7.
https://doi.org/10.1145/3204493.3204532

We propose a technique for the gaze-based acquisition ofmoving targets by pseudo stopping the target for the time
predicted by Fitts’ Law, after saccades have been detected.
Therefore, this technique enables the acquisition of targets
moving at various speed and with different widths. Moreover,
we are currently attempting to develop a system for theacquisition of targets in virtual reality (VR) and augmentedreality (AR), using the proposed technique.