Tactile Symbol Discrimination on a Small Pin-array Display

Abstract

Pin-array displays are a promising technology that allow to display visual information with touch, a crucial issue for blind and partially sighted users. Such displays are programmable, therefore can considerably increase, vary and tailor the amount of information as compared to common embossed paper and, beyond Braille, they allow to display graphics. Due to a shortage in establishing which ideal resolution allows to understand simple graphical concepts, we evaluated the discriminability of tactile symbols at different resolutions and complexity levels in blind, blindfolded low-vision and sighted participants. We report no differences in discrimination accuracy between tactile symbols organized in 3x3 as compared to 4x4 arrays. A metric based on search and discrimination speed in blind and in low-vision participants does not change at different resolutions, whereas in sighted participants it significantly increases when resolution increases. We suggest possible guidelines in designing dictionaries of low-resolution tactile symbols. Our results can help designers, ergonomists and rehabilitators to develop usable human-machine interfaces with tactual symbol coding.

Displaying easily recognizable tactile pictures: A comparison of three illustration techniques with blind and sighted children

“…These studies showed high recognition rates. Depending on the size of the matrix and the space between the pins the recognition rates varied from 60% to 90% in blind and sighted adults (Bellik & Clavel, 2017;Leo, Baccelliere, Waszkielewicz, Cocchi, & Brayda, 2018;Velazquez et al, 2008). Moreover, Zarate et al (2017) showed that several usage scenarios for people with visual impairments can be implemented with their Blindpad device (12 × 16 matrix of 4 mm pins spaced 4 mm apart).…”

Surface Haptics

“…One way to take the advantage is by using pin array stimulation. The spatiotemporal patterns of the pin array can be used to convey information such as directions and icons [8,9]. In this tutorial, Jingun Jung describes two studies using PinPad hardware that combines a pin array and a touchpad.…”