Seungjae Oh

Vibrotactile Illusion

Seamless Phantom Sensation Moving across a Wide Range of Body
(IEEE World Haptics 2019)

overview

Abstract

This paper reports experimental research aimed to provide seamlessly moving illusory tactile sensations across a large area of the body using a few vibration actuators. The human vibrotactile sensitivity differences among the body sites are calibrated using empirically-measured psychophysical magnitude functions.

We present a new phantom sensation rendering method that uses the Gaussian function emphasizing the spatial continuity of perceived movement and the temporal consistency of perceived intensity. We demonstrate that our rendering method outperforms previous methods for phantom sensations via a perceptual experiment. Our method is tailored to eliciting the perception of illusory tactile sensation moving in a long distance, from the thigh to the upper back.

Publication

Figure

pi The results of a magnitude estimation experiment about vibration at four different body sites (Exp 1). Each curve represents the relationship between the amplitudes of physical stimulus and their perceived intensity.

lin log pilin pinorm Four rendering methods for phantom sensations. The first two are common rendering functions for phantom sensations, and the latter two are compensated by the results of our magnitude estimation experiment.

Result The percieved qualities of phantom sensations with respect to the rendering methods and stimulus durations (Short: 0.75 s; Middle: 1.5 s; Long: 2 s).

Conclusion

The work reported in this paper aimed to design a rendering method for dynamic phantom sensations that deliver realistic illusory tactile sensations moving across a wide range of the body, from the thigh to the upper back, with a few actuators. In order to compensate for the sensitivity differences across the body, we measured in Exp. I four psychophysical magnitude functions of vibrotactile stimuli at the four body sites of thigh, waist, hip, and upper back. Then we designed a new phantom sensation rendering method that uses the Gaussian function in the profile of perceived intensity to support smoother transitions at even actuator locations. Our method was evaluated in Exp. II along with three other previous rendering methods. Results indicated that our method provides illusory motion of the best quality in terms of the spatial continuity of movement and the temporal consistency of intensity. Our findings can contribute to appropriate designs of tactile displays and rendering algorithms stimulating the body in a long distance.

Contribution

  • Gyeore Yun: Idea, Implementation (HW&SW), Experiment, Experimental Design and Analysis, Graphics, and Video
  • Seungjae Oh: Idea, Ideation, and Experimental Design
  • Seungmoon Choi: Director