The idea of Homère emerged at a seminar run by the Institut pour la ville en mouvement attended by blind and partially sighted people at the Cité des Sciences in April 2001. They spoke of the way in which they use multi-sensory perception to find their way around and assess their environment. They also described the difficulty of trying to move around an unfamiliar place, assessing distances and possible obstacles, and identifying points of interest .
This meeting gave rise to the idea of adapting the Virtual Reality techniques with which the three designers are heavily involved in their specific ways: driving simulators at PSA, tactile and effort return interfaces at CEA-List, and comprehensive solutions based around multi-sensory interfaces at ONDIM.
Given the highly innovative nature of the approach in this field, we needed to demonstrate that these technologies can be used to open new avenues for the development of products and services to assist the visually impaired. Work was begun with the help of the Institut pour la ville en mouvement (http://www.ville-en-mouvement.com) on a demonstrator designed to improve their autonomy of movement in urban areas.
With the contribution of accessibility and ergonomics experts like Hoëlle Corvest of the Cité des Sciences et de l'Industrie and Gérard Uzan from the University of PARIS V, together with the strong backing and commitment of the developers, this demonstration model was produced in record time using technologies that are themselves still at the research and development stage.

The heart of the system, housed in Homère's CPU, is a "virtual model" of the Cité des Sciences et de l'Industrie. This can be described as a three-dimensional (length, width, height) map containing a plethora of information:

• First the geometry. It is this that tells the virtual pedestrian the length of the journey, the number of changes of direction and level, the shape of the different elements or obstacles along the route, etc.

• Superimposed on this geometry is the "texture" information, which represents the tactile properties of the elements the user will encounter, such as the floors or walls (smooth or rough, gravel or grass, hard or soft).

• Also described are the acoustic characteristics of the floors, so that visitors can link their progress with the sound of their footsteps and of the virtual white stick tapping or crunching on gravel.

• Each location is also associated with an acoustic ambience: the hum of voices in a hall, game noises in a children's play area, the closing of a door.

Finally, to complete the palette of sensations and enhance the realism, the virtual tour takes place on a sunny day which is suggested by an infrared simulator that varies and adjusts the position of a virtual sun. This provides another means for the visitor to interpret changes of direction along the route.

A charming virtual "guide" will welcome visually impaired visitors at the entrance, and conduct them virtually from a bus stop along the route into the Cité des Sciences, which begins in the square, continues inside the two levels of the Cité until finally reaching the Géode. Along the route, the sound of the guide's virtual steps will indicate the direction to follow. The same guide will, at the user's request, provide commentary on points of interest along the way.

To make a tour of this "virtual model", the visitor has a virtual white stick to explore the immediate environment. The sense of touch is provided by a Virtuose effort-return arm developed by CEA-List and distributed by the firm HAPTION. This device enables the user to feel the characteristic forces and vibrations experienced during movement when the virtual stick strikes an obstacle or slides on the floor or along a wall. In the technical reality, Virtuose uses sensors to "read" the stick's position and transforms it into a "virtual position" in the previously modelled environment. This triggers sensory feedback to the user, who experiences sensations generated by a set of finely tuned microelectric motors.

The second source of information for the user is sound. A quadriphonic sound system localises sounds in the space around the visitor to help with interpretation.

The final source of information Homère uses is the feeling of the sunlight on the skin. Homère knows the user's position relative to the sun at any given time, and controls a simulator that directs the heat from infrared lamps towards the user, changing the source of the virtual sunbeams as the visitor moves around.

With Homère, users can go over their route as many times as they want in order to memorise all the sensory perceptions they will find along the actual tour route. Homère is thus a sort of "three-dimensional map reader", or "multi-sensory tourist guide", especially provided for visually impaired visitors.

Innovative and unique, Homère is still a newborn, but already its first-steps technology suggests its potential capabilities.

Many unknowns remain and further research will be required before a fully operational concept is achieved:

• First of all, the haptic rendering , a central theme of this demonstrator, is the subject of extensive research in a multitude of public and private research laboratories around the world. This is certainly the area where Homère will help us advance and where significant improvements can be made in the short term.

• Secondly, it may be that the current restricted set of sensory perceptions is not enough and that other sense experiences such as odour or wind direction will prove helpful.

• Other interfaces that simulate more points of contact, such as the feet on the ground, could also be envisaged.

By analysing the information that will be collected from Homère users, we will be able to lay the foundations of new forms of assistance for the blind.

In this initial version, Homère is already a real revolution. At the very least, it will promote the idea of new concepts in support for the disabled with public bodies and potential partners, and thereby help change mindsets for future and subsequent developments.

They are fantastic! First, mobility support for the visually impaired in public places such as stations, museums, administrative buildings, etc. in the form of interactive terminals. Then the possibility of extending this service to a whole city and all its sites of interest, with terminals located at its busiest points (metro and station exits, tourist offices, etc.).
For teaching purposes inside associations or schools, to teach partially sighted young people to find their way around and respond in new environments, in other countries, other cultures, to teach them geography, history, architecture, art...

Finally, CEA's researchers are working on mobile tactile interfaces which could perhaps be geolocated inside buildings by a GPS or equivalent system. This tactile interface, which might resemble a hand-held PDA carried users as they move around, will guide and warn them in advance of any upcoming obstacles on their route.

The HOMERE demonstrator is a first tentative step in a field where nothing previously existed. In creating it, we have tried to work fast and to the best of our ability, by unveiling ourselves of the skills of the APAM and Paris V University's laboratory of Computer Ergonomics. We wanted to give concrete form to an idea and, by exposing it to the reactions of its intended users, to assess its relevance and demonstrate its potential for improvement.

This is the raison d'etre of the Institut pour la ville en mouvement, whose role it is to promote and provide the momentum needed for the emergence of new ideas, in cooperation with users, industries and research laboratories.

This exciting project is driven by powerful social and societal aspirations. Its aim is to use and to develop new technologies in such a way that they serve the whole community, and in particular that they contribute to resolving the problems of groups in the population who face specific difficulties. Mobility today is a generic right which prefigures all other rights (work, housing, social life..). To be hindered or handicapped in one's ability to move around the city, is to experience in aggravated form all the exclusions that disability can impose. The blind have a right to the city, to the pleasure of movement, to tourism …