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3 December 2014

WAI R&D Symposia » Way-Finding Home » Proceedings » This paper.

This paper is a contribution to the Accessible Way-Finding Using Web Technologies. It was not developed by the W3C Web Accessibility Initiative (WAI) and does not necessarily represent the consensus view of W3C staff, participants, or members.

Extended Abstract for the RDWG Symposium on Accessible Way-Finding Using Web Technologies

Campus navigation for blind people via mobile web based applications

  • Ian Pitt, University College Cork, Ireland, ianp@cs.ucc.ie
  • Tracey Mehigan, Dublin City University, tmehigan@computing.dcu.ie

1. Problem Addressed

Navigating around a university campus can be difficult for visitors and incoming students/staff, and is a particular challenge for those who are blind or have impaired vision. Over the last few years we have conducted a number of studies in this area and have developed and tested a number of practical solutions. We believe the results of this work can be applied to the design of way-finding systems for other types of environment, and also to the specification of future tools/technologies.

University College Cork (UCC), like most other universities and similar institutions worldwide, relies mainly on sign-posts and maps (available from the college website) to direct students and visitors around campus. These are not appropriate for vision-impaired users. UCC's Disability Support Service provides mobility training to enable blind and vision-impaired students and staff to safely and independently navigate around the campus. This is time-consuming for all parties and is costly to provide. It is also route-specific: for example, if a blind student who has already received mobility training is required to attend lectures in a building they have not previously visited, they may require further training on the new route. It is not feasible to provide this kind of training for blind/visually-impaired visitors.

2. Background

There have been a number of attempts in recent years to develop efficient and cost-effective systems that enable blind and vision-impaired pedestrians to safely and independently navigate spaces with which they are not familiar. These include the Drishti system [1], and other care-giving monitoring systems for location-based information such as that proposed by Tee et al [2]. Researchers have also developed navigation solutions tailored for use at exhibitions [3] and museums [4]. Several commercial systems are also available, such as the Trekker Breeze GPS System [5] and the Mobile Geo [6].

Most of these systems are based on one or more of the following technologies: Radio Frequency Identification (RFID), Bluetooth, Dead-Reckoning systems using accelerometer devices, and Global Positioning Systems (GPS). Nokia Research Labs have developed a high-accuracy indoor positioning system delivered via Bluetooth 4.0 [7].

3. Strategy

In order to develop an understanding of the needs of people with vision-impairments navigating the UCC campus, a series of interviews and walkabouts were undertaken. Those involved were students taking a range of courses and with varying levels of familiarity with the campus - some were newly-arrived whilst others were in their final year. The group included both guide-dog and white-cane users. An interview and campus walkabout with UCC’s mobility trainer was also conducted. Participants were asked to comment both on general issues regarding navigation around campus, on issues associated with particular routes, and on the strengths and weaknesses of existing mobility training and support. During the walkabouts, participants were asked to describe their thought processes and the cues and techniques they used to determine their position and orientation at each stage of the journey.

The study highlighted differences between the long-cane users, who need to check and correct their position every few steps, and guide-dog users, who require less frequent position checks but must be able to identify route decision-points with great accuracy if they are to instruct the dog to follow a route with which it is not familiar. It also illustrated the extent to which both groups make use of environmental sounds either as a primary means to determine position or to confirm information obtained through other means. For example, many of those interviewed reported using manholes as route-markers: they were able to distinguish aurally between the different manholes (silence, various degrees of water flow, etc.), whilst walking across a manhole is easily distinguishable from walking over solid ground. The river which flows through campus also provides a useful auditory cue for many. Most participants reported that the area which causes them most difficulty is the Honan Plaza, a large, open space with little variation in terrain and few useful sources of sound.

Following the review, a statement of user requirements was developed and existing solutions were reviewed. These included both commercial systems such as the Trekker Breeze [5] and experimental/one-off solutions described in the research literature (e.g., [3]).

It was concluded that there is no existing system that fully meets UCC's requirements. All of the candidates fall short in at least one of the following areas: the accuracy of the feedback provided; ability to operate both indoors and outdoors and facilitate a smooth transition between indoor and outdoor navigation; power-drain and battery life; ability to successfully convey an impression of terrain and environment via hearing and touch. While most of existing systems use synthetic speech to provide navigation cues to users, there are problems in providing the information in ways that do not overload sensory channels or conflict with other demands on these channels. There are also issues concerning the use of such systems alongside other mobility aids, such as a long cane. In many cases these systems are cumbersome and can isolate the user.

We have developed a system that can run on a variety of platforms and has two distinct layers - a navigation layer that obtains data on position and orientation, and an interface layer that makes this information available to the user. Separation of the two layers allows development to proceed independently, and also makes it easier to upgrade or replace one layer without unnecessarily affecting the other.

4. Major Difficulties

The principle difficulty faced in this work has been obtaining sufficiently accurate positioning information, and doing this consistently. Various GPS systems were tested, but none offered sufficient and consistent accuracy across the campus. Using Bluetooth beacons provided much greater accuracy but at considerable cost. The navigation layer currently supports both GPS and ULP Bluetooth 4.0 combined with Wireless Inertial Measurement Units (WIMU).

The user interface also presented challenges. It has been designed to address issues apparent in other systems while retaining beneficial elements of those systems. We have extended the feedback to include audio and haptic components as well as speech and text/graphics. However, as many vision-impaired users rely on environmental sounds and use echo-location to gather information on their surroundings, we have given users extensive control over the way in which information is presented and ensured that information can be received effectively without the use of headphones. Attention has also been paid to needs of users with differing levels of experience (casual/one-off user, beginner, expert), and of the differing requirements of guide-dog users and long cane users. As most modern devices (for example the iPhone) use touch-screens, gesture-based system controls have been implemented.

5. Outcomes

The system is still under development, but initial user trials have produced encouraging results [8]. Six subjects took part in the trials, three guide-dog users and three cane users. All completed the test routes successfully and said that they would use the system again. The most popular feature was the haptic feedback facility, while the most common criticism was inadequate control over the audio feedback. Further work is needed to find an appropriate balance between ease of set-up for first use and flexibility in interaction options.

6. Open Research Avenues

A navigation system that makes use of mobile and wireless technologies could allow blind and vision-impaired people to accurately orientate themselves and navigate independently. If such a system were web-based and therefore platform-independent, it would avoid the need for specialist accessibility hardware and allow individuals to use their own mobile devices, thus addressing some of the inclusion issues currently faced by those with vision-impairments.

References

  1. A.S. Helal, S.E. Moore and B. Ramachandran (2001) Drishti: An Integrated Navigation System for Visually Impaired and Disabled, in Fifth International Symposium on Wearable Computers, Zurich, Switzerland, pp. 149-156
  2. Z. Tee, L.M. Ang, K.P. Seng, J.H. Kong, R. Lo and M.Y. Khor (2009) SmartGuide System to Assist Visually Impaired People in a University Environment, in Third International Convention on Rehabilitation Engineering & Assistive Technology (ICREAT 2009), Singapore, IETE Technical Review pp. 455-464
  3. F. Bellotti, R. Berta, A. De Gloria and M. Margarone (2006) Guiding visually impaired people in the exhibition, in Virtuality 2006, Mobile Guide Workshop, Turin, Italy, http://hcilab.uniud.it/sigchi/doc/Virtuality06/Bellotti&al.pdf
  4. C. Santoro, F. Paterno, G. Ricci, G. and B. Leporini (2007) A Multimodal Mobile Museum Guide for All, A Multimodal Mobile Museum Guide for All, in Mobile Interaction with the Real World (MIRW 2007), pp. 21-25
  5. HumanWare http://www.humanware.com/en-usa/products/blindness/talking_gps/trekker/_details/id_88/trekker_talking_gps.html
  6. Mobile Pocket Speak http://www.codefactory.es/en/products.asp?id=336
  7. K. Kalliola (2011) High Accuracy Indoor Positioning System on BLE, Nokia Technical Report, HighAccuracyIndoorPositioningBasedOnBLE_Kalliola_270411.pdf
  8. T. Mehigan and I. Pitt (2012) Harnessing Wireless Technologies for Campus Navigation by Blind Students and Visitors. Proceedings of the 13th International Conference on Computers Helping People with Special Needs, Linz, Austria, July 11-12th 2012, published as Lecture Notes for Computer Science 7383, Springer, Berlin, ISBN 978-3-642-31533-6, pp.67-74