Giudice, G.B. – VEMI Lab /vemi University of Maine Thu, 08 Oct 2020 15:12:10 +0000 en-US hourly 1 https://wordpress.org/?v=6.8.5 Touchscreen-based Haptic Information Access for assisting Blind and Visually-Impaired Users: Perceptual Parameters and Design Guidelines /vemi/publication/touchscreen-based-haptic-information-access-assisting-blind-visually-impaired-users-perceptual-parameters-design-guidelines/ Mon, 09 Jul 2018 21:05:58 +0000 /vemi/?post_type=publication&p=1858 Touchscreen-based smart devices, such as smartphones and tablets, offer great promise for providing blind and visually-impaired (BVI) users with a means for accessing graphics non-visually. However, they also offer novel challenges as they were primarily developed for use as a visual interface. This paper studies key usability parameters governing accurate rendering of haptically-perceivable graphical materials. Three psychophysically-motivated usability studies, incorporating 46 BVI participants, were conducted that identified three key parameters for accurate rendering of vibrotactile lines. Results suggested that the best performance and greatest perceptual salience is obtained with vibrotactile feedback based on: (1) a minimum width of 1mm for detecting lines, (2) a minimum gap of 4mm for discriminating lines rendered parallel to each other, and (3) a minimum angular separation (i.e., cord length) of 4mm for discriminating oriented lines. Findings provide foundational guidelines for converting/rendering visual graphical materials on touchscreen-based interfaces for supporting haptic/vibrotactile information access.

Keywords: Assistive Technology, Haptic information access, Haptic interaction, Multimodal interface, Design Guidelines

Citation:

Palani, H.P., Tennison, J.L., Giudice, G.B., & Giudice, N.A. (2018). Touchscreen-based haptic information access for assisting blind and visually-impaired users: Perceptual parameters and design guidelines. In: Ahram T., Falcão C. (eds.) Advances in Usability, User Experience and Assistive Technology, part of  the International Conference on Applied Human Factors and Ergonomics (AHFE’18). Advances in Intelligent Systems and Computing, vol 798, (Pp. 837-847). Springer, Cham.

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]]> Haptic Information Access using Touchscreen Devices: Guidelines for Accurate Perception of Angular Magnitude and Line Orientation /vemi/publication/haptic-information-access-using-touchscreen-devices-design-guidelines-accurate-perception-angular-magnitude-line-orientation/ Sat, 24 Feb 2018 16:36:49 +0000 /vemi/?post_type=publication&p=1763 The overarching goal of our research program is to address the longstanding issue of non-visual graphical accessibility for blind and visually impaired (BVI) people through development of a robust, low-cost solution. This paper contributes to our research agenda aimed at studying key usability parameters governing accurate rendering and perception of haptically-accessed graphical materials via commercial touchscreen-based smart devices, such as smart phones and tablets. The current work builds on the findings from our earlier studies by empirically investigating the minimum angular magnitude that must be maintained for accurate detection and angular judgment of oriented vibrotactile lines. To assess the minimum perceivable angular magnitude (i.e., cord length) between oriented lines, a psychophysically-motivated usability experiment was conducted that compared accuracy in oriented line detection across four angles (2°, 5°, 9°, and 22°) and two radiuses (1-inch and 2-inch). Results revealed that a minimum 4mm cord length (which corresponds to 5° at a 1-inch radius and 2° at a 2-inch radius) must be maintained between oriented lines for supporting accurate haptic perception via vibrotactile cuing. Findings provide foundational guidelines for converting/rendering oriented lines on touchscreen devices for supporting haptic information access based on vibrotactile stimuli.

Keywords: Assistive Technology, Haptic information access, Haptic interaction, Multimodal interface, Design Guidelines

Citation:

Palani, H.P., Giudice, G.B., and Giudice, N.A. (2018). Haptic Information Access on Touchscreen devices: Guidelines for accurate perception and judgment of line orientation. Proceedings of the 20th annual conference on Human-Computer Interaction (HCI International’18). Las Vegas, NV. July 15-18 (corresponding author).

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