Using Low-frequency Sound to Create Non-contact Sensations On and In the Body

Author

Waseem Hassan, Asier Marzo, Kasper Hornbæk, CHI 2024

Keywords

Vibrotactile Feedback; Midair, Non-contact Haptics; Psychophysics; Low Frequency Sounds; Room Modes

WHAT

  • explores the perceptual effects ofthese low-frequency sounds and investigates the potential of this method for delivering whole-body sensations

WHY

  • The use of low-frequency sounds for delivering sensations has not yet been explored in the field of HCI

  • overcomes the limitations of existing haptic technologies

  • eliminates the need for wearable or contact-based devices and facilitates a more natural and diverse set of interaction scenarios

HOW

  • Quantitive Characterization

    • Material

      • Room Specifications

        • a controlled environment

        • a consistent and isolated acoustic environment

        • MDF

      • Signal Generation and Recording

        • MATLAB

        • 1200-watt class D amplifier

        • Blue Yeti condenser microphone set to Omni mode

    • Methodology

      • 45 sampling points in the room to evaluate the pressure

    • Data Analysis

      • normalization

      • FFT

      • MAE

      • spatial gradients

      • use a cuboid unit for mitigating the impact of localized anomalies

    • Results

      • Mean Absolute Error

      • Pressure Distribution Trends

      • Discussion

        • the quantitative differences in the slopes of the pressure fields are noteworthy

        • it is important to consider the implications for human perception

        • the directional trends or gradients in pressure changes may carry greater significance when evaluating their perceptual impact

  • Perceptual Characterization

    • Experimental Design

      • Stimuli

        • Two regions with the highest cumulative pressure were selected for each mode

      • Apparatus

        • provided with earplugs

        • same as former experiments

    • Participants

      • 4 females 10 males

      • average height 172.8cm

      • 45 minutes

    • Procedure

      • A reference stimulus containing all 14 modes was played as training

      • 5 seconds stimuli in certain areas

      • feedback

        • rated the intensity of the sensation, using Likert Scale

        • provided detailed verbal descriptions of the sensations

        • identified and marked any area(s) on a chart of the human body where they experienced sensations.

    • Data Analysis

      • Sensation Intensity

        • non-normal distribution

      • On-Body Sensation Mapping

        • normalization

      • Verbal Sensation Descriptions

        • thematic analysis

Results

  • sensation intensity

    • Most of the responses were between three and six which shows that most participants felt intermediate to high intensity

  • on-body sensation

    • The intensity was mostly felt on the feet, thighs and chest

    • The intensity was felt less on the back of the body, arms and neck

    • According to the participants the sensations was mostly felt in the legs and thighs

  • verbal sensation description

    • Used to identify recurring themes or to understand how the different modes are perceived by users

    • Commonly used Descriptors

      • vibration, vibrating, or vibrate

    • Sensation Consistency with Simulated Pressure

      • Consistent

      • Contradictory

    • Emergent Perceptual Properties

      • Within body sensations

      • Focal point of the sensations within the body

Discussion

  • Non-contact Sensation On, In, and Across the Body

    • Inducing Non-contact Sensations

    • Within-body Sensation: A New Frontier

    • Local and Global Sensations

  • How to Create Sensations Reliably

  • Use Case Scenarios

  • Limitations