New VEMI research on guidelines for non-visual graphical access

VEMI researchers publish new paper providing guidelines and best practices for non-visual access to graphical material using touchscreen-based haptic interfaces. The article, published in the International Journal of Human-Computer Interaction (IJHCI), synthesizes the results of a series of six studies with both blind and sighted participants evaluating the efficacy of the vibro-audio interface previously developed in VEMI. Results provide a definitive set of empirically-derived parameters for using this interface in an intuitive and perceptually-valid manner and have relevance to any researchers/developers studying and designing touchscreen-based haptics for non-visual and eyes-free applications.

Abstract: This paper explores the viability of new touchscreen-based haptic/vibrotactile interactions as a primary modality for perceiving visual graphical elements in eyes-free situations. For touchscreen-based haptic information extraction to be both accurate and meaningful, the onscreen graphical elements should be schematized and downsampled to: (1) maximize the perceptual specificity of touch-based sensing and (2) account for the technical characteristics of touchscreen interfaces. To this end, six human behavioral studies were conducted with 64 blind and 105 blindfolded-sighted participants. Experiments 1–3 evaluated three key rendering parameters that are necessary for supporting touchscreen-based vibrotactile perception of graphical information, with results providing empirical guidance on both minimally detectable and functionally discriminable line widths, inter-line spacing, and angular separation that should be maintained. Experiments 4–6 evaluated perceptually-motivated design guidelines governing visual-to-vibrotactile schematization required for tasks involving information extraction, learning, and cognition of multi-line paths (e.g., transit-maps and corridor-intersections), with results providing clear guidance as to the stimulus parameters maximizing accuracy and temporal performance. The six empirically-validated guidelines presented here, based on results from 169 participants, provide designers and content providers with much-needed guidance on effectively incorporating perceptually- salient touchscreen-based haptic feedback as a primary interaction style for interfaces supporting non-visual and eyes-free information access.

To read the full paper, see:

Citation: Palani, H.P., Fink, P.D.S., & Giudice, N.A. (2020), Design Guidelines for Schematizing and Rendering Haptically Perceivable Graphical Elements on Touchscreen Devices. International Journal of Human-Computer Interaction. Online-first publication: DOI: 10.1080/10447318.2020.1752464