Vibrotactile Guidance for Wayfinding of Blind Walkers - eScholarship (2015)

IEEE TRANSACTIONS ON JOURNAL NAME, MANUSCRIPT ID Vibrotactile Guidance for Wayfinding of Blind Walkers G. Flores, S. Kurniawan, R. Manduchi, E. Martinson, L. Morales, E.A. Sisbot Abstract— We propose a vibrotactile interface in the form of a belt for guiding blind walkers. This interface enables blind walkers to receive haptic directional instructions along complex paths without negatively impacting users’ ability to listen and/or perceive the environment the way some auditory directional instructions do. The belt interface was evaluated in a controlled study with 10 blind individuals and compared to the audio guidance. The experiments were videotaped and the participants’ behaviors and comments were content analyzed. Completion times and deviations from ideal paths were also collected and statistically analyzed. By triangulating the quantitative and qualitative data, we found that the belt resulted in closer path following to the expense of speed. In general, the participants were positive about the use of vibrotactile belt to provide directional guidance. Index Terms— Assistive technology, haptic belt, wayfinding. I NTRODUCTION Navigation through unknown environments remains a significant challenge for the visually impaired. Despite technological advances that have enabled increased mo- bility, the problem is far from solved given the existing sensing, localization, and interface technologies. Im- proved sensing enables rapid re-planning in a dynamic environment, both by a computer and the individual. Im- proved localization allows for more effective guidance from point to point, bypassing the errors common to GPS- based navigation (a technology that has received good acceptance by the blind community). And an improved interface lets the visually impaired user make the most effective decisions, reducing time, distance, and/or con- fusion when using the technology. In this work, we focus primarily on improved interface, proposing a vibrotactile system for guiding blind walkers. We evaluate the system in a controlled study with 10 blind individuals, compar- ing our proposed vibrotactile guidance with an auditory one. The interface developed is a belt to be worn about the user’s waist. Instead of communicating directions via an auditory interaction, the belt contains a number of vibra- tion motors, which can be turned on to indicate a direc- tion of travel. The advantage of vibration is that it is an otherwise unused communication channel; it does not interfere with users’ ability to perceive other environmen- tal events, as does auditory feedback, but is still easily recognizable with a limited added cognitive load. This is important because as localization technologies improve, reaching 10 cm accuracy or better, the complexity of the path a visually impaired person can be guided along will also increase – keeping people outside dangerous areas near construction sites, within crosswalks, and in line with elevators, doors, and other narrow openings. Using an acoustic interface to help a blind person follow these trajectories may require too many verbal instructions, occluding otherwise important auditory events. Vibra- tion, by contrast, can be used continuously to describe complex paths, without masking important clues from the environment. In the remainder of this work, we will first summarize the state-of-the-art in nonvisual interfaces for navigation systems. Then we will present two interfaces for guiding people along complex paths: our proposed belt interface, and an auditory spoken dialogue system. In Section 4, the user testing scenarios are described, including the envi- ronment, the testing objectives, and supporting hardware. Sections 5 and 6 then discuss the quantitative and qualita- tive results of the study. Finally, in Section 7 we compare and contrast the benefits of either interface. Technology that can support safe and efficient wayfind- ing may have tremendous potential for improving the quality of life of people with visual impairments. Non- visual navigation systems may also find application in other domains, such as search and rescue (e.g. in a burn- ing building with thick smoke) or combat zones. Two types of non-visual interface are available: acoustic and tactile. We review the related literature for these two in- terface types in the following. • G. Flores, S. Kurniawan, R. Manduchi, and L. Morales, L. are with the School of Engineering, University of California, Santa Cruz, CA 95064. E-mail: [ghflores,skurnia,manduchi,lommoral]@ucsc.edu • Martinson, E. and Sisbot, E. A. are with Toyota InfoTechnology Cen- ter, USA, Mountain View, CA 94043. Email: [emartinson,asisbot] @us.toyota-itc.com xxxx-xxxx/0x/$xx.00 © 200x IEEE R ELATED W ORK Acoustic Interface for Wayfinding Audio signals for directional guidance can be in the form of synthetic speech (or spatial language , e.g.: turn left , go straight ) or non-verbal acoustic sound. Non-verbal sound is often spatialized , that is, generated in a binau- ral form to create the impression of sound generating from a certain point in space. For example, the NavBelt Published by the IEEE Computer Society