MoBIC: user needs and preliminary design for a mobility aid for blind and elderly travellers

Thomas STROTHOTTE (1), Helen PETRIE (2), Valerie JOHNSON (2) and Lars REICHERT (3)

(1)Department of Simulation and Graphics, Otto-von-Guericke University of Magdeburg,
Universitätsplatz 2, D-39106 Magdeburg, Germany

(2)Sensory Disabilities Research Unit,Psychology Division, University of Hertfordshire,
Hatfield, HERTS AL10 9AB, U.K.

(3)Department of Computer Science, Free University of Berlin,
Takustrasse 9, D-14195 Berlin, Germany


Abstract

This paper presents the initial research for the development of a new travel aid to increase the independent mobility of blind and elderly travellers. The MoBIC travel aid consists of two interrelated components: the MoBIC Pre-Journey System (MoPS) to assist users in planning journeys, and the MoBIC Outdoor System (MoODS) to execute these plans by providing users with orientation and navigation assistance during journeys. The MoODS is a secondary aid, complementing primary aids such as the long cane or guide dog. We outline the results of our user needs survey and the preliminary design of the MoBIC travel aid.

1. Introduction

The MoBIC travel aid aims to increase the independent mobility of blind and elderly travellers in potentially unfamiliar environments by providing useful information both before and during a journey. This information will be derived from the Global Positioning (satellite) System (GPS) and will assist the traveller in orientation and navigation. By orientation we mean perceiving and understanding the spatial relations between one's own position and relevant features in the medium to distant environment; by navigation we mean finding one's way along a potentially pre-planned route to reach a destination. To ensure that the MoBIC travel aid is of maximal use to travellers, the first step of the MoBIC Project has been to undertake an extensive investigation of user needs. Based on this study, hardware and dialogue systems have been designed and are under development. In this paper we report on our initial results in these two areas.

2. Elicitation of user needs

To understand the needs of blind and elderly people in relation to the MoBIC aid, a number of studies are being undertaken within the MoBIC Project. Firstly, interviews have been conducted with blind and partially sighted individuals concerning their current travel habits and problems which they encounter in travelling in both familiar and unfamiliar environments, their ideas on what information the MoBIC travel aid could provide to them and how that information should be presented. Secondly, interviews have been conducted with teachers of mobility training and other individuals involved in this area, such as trainers of these teachers. Discussion groups have also been held with blind and elderly (sighted) people to elicit more general information about their views on the MoBIC aid. Now practical studies are being conducted in which potential users are given mock-ups of aspects of the travel aid for assessment.

In this paper we will concentrate on the information obtained from the in-depth interviews conducted with 24 blind and partially sighted individuals in the U.K. Fifteen of the interviewees were male and nine were female. Ages ranged from 26 to 75 years with a mean age of 40 years. This means that the sample does not accurately reflect the profile of the blind and partially sighted population in the U.K., as it has been estimated that 90% of blind and partially sighted people are over 60 years of age [1], but interviewees were selected such that the needs of a wide range of blind and partially people would be elicited. Thus, the sample included both long cane users and guide dog users, congenitally blind and adventitiously blind people, those registered as blind and those not registered. We also sought to include some people who travel extensively independently and some who do not travel at all independently in order to investigate how the MoBIC system can be of benefit to both increase the independent mobility of people who already travel, but also allow those who do not currently travel independently to do so.

Table1: Suggestions for useful general information to be provided by the MoBIC Travel Aid

directions to required destination
for example: number of streets/turns, distances
Name of streets
including: numbers of building in street
traveller's current location
including: direction currently facing/travelling
Shops
for example: shops which are likely to have stands, tables etc. outside
Information about current roadworks
Pedestrian crossings
including: whether it has an auditory signal
layout of complex crossings
Useful buildings and landmarks
for example: banks (including location of ATMs)
doctors' surgeries
Layout of environment
for example: changes in pavement surfaces/levels
steps/underpasses
street furniture
for example: parking meters
lamp posts
Useful items in street
for example: post boxes
public telephones

Table 1 shows some of the suggestions which were made by interviewees for useful information which might be provided by the MoBIC travel aid (all suggestions listed here were made by more than 50% of the interview sample). Interviewees were also asked about how this information should be presented, particularly when they are out on a journey. They were asked to rate a number of possibilities on a scale from 1 (=definitely would not want/use this option) to 7 (= would be perfectly happy with this option). The most popular output option was synthetic speech (mean rating 6.25), with other sounds and vibratory information significantly less popular (mean ratings 3.39 and 3.45 respectively; F 2,44 = 627.43, p < 0.0001). These results and many others have been used to develop the first design for the MoBIC travel aid.

3. The MoBIC Pre-Journey System (MoPS)

A fundamental feature of the MoBIC system is the availability of facilities for a blind user to plan his or her journey before actually beginning it. This planning can be carried out with standard office hardware for blind persons, along with specialised MoBIC software for the planning activity.

The heart of MoPS is an object-oriented database system used to organise the data which is relevant of the user's planning task. It contains such data as: In addition, there are data which are specific to the needs of blind travellers: Finally, users have the ability to store personal information, such as addresses and preferences, in order to improve the quality of the dialogue.

Users interact with MoPS to explore an area with the goal of building up a mental model of it. The exploration of the map is carried out in a fashion which extends the interaction techniques used by the Arkenstone system [2] by a component for kinaesthetics using a touch tablet with auditory feedback. Furthermore, MoPS enables users to plan a particular route for their journey. To assist them in this process, the system has route-calculation algorithms which take into consideration user preferences for ease of travel for the blind traveller while optimising such parameters as time to travel or the distance to walk.

4. The MoBIC Outdoor System (MoODS)

Once the user has planned the journey, MoODS system guides him or her en route and provides access to additional information which may be relevant. The hardware consists of a notebook computer with peripheral devices, the most important of which is a GPS receiver, supplemented by hardware for a differential signal. In addition, an electronic compass is provided for tuning the system's output to the user.

The user interacts with the system by asking questions using a small, hand-held keyboard- like device and receiving answers acoustically. Special keys are reserved for questions like "Where am I?", "Where should I proceed from here?" and "Public transport information". It is important to note that the MoBIC system itself is intended for the informational needs of travellers with respect to their overall journey. It does not provide information on a low level, such as whether there is an obstacle temporarily blocking the way. Such information must be obtained in other ways, such as using the long cane.

5. Conclusion

The user needs study, the first step in developing the MoBIC system, has been completed, as has the development of a first version of the MoODS hardware. The MoPS hardware is expected for the Summer of 1995. First small-scale field trials will be carried out toward the end of 1995, followed by any necessary re-working of the dialogue system and a large-scale field trial in 1996. While technological developments will entail an evolution in the hardware facilities over the coming years, the set of MoBIC user requirements and their evaluation will serve to guide future developments in this area of research and development.

Acknowledgements

The research is supported by the TIDE Programme (Technology Initiative for Disabled and Elderly Persons) of the European Union. We are grateful to all the blind, partially sighted and elderly people and those involved in mobility training who have participated in the research. The partners in the project are British Telecom, F.H. Papenmeier GmBH and Co. KG, Free University of Berlin, Royal National Institute for the Blind, University of Birmingham, University of Hertfordshire, University of Magdeburg, and Uppsala University,

References

[1] I. Bruce, A. McKennell and E. Walker, Blind and partially sighted adults in Britain: the RNIB survey. Volume 1, Her Majesty's Stationery Office, London.
[2] J. Fruchterman. Arkenstone's orientation tools: AtlasSpeaks and Strider. Presentation at Conference on Orientation and Navigation Systems for Blind Persons, University of Hertfordshire, 1995.


Presented at the 2nd TIDE congress, Paris, La Villette, 26 - 28 April 1995