By Geoff Adams-Spink
Age & disability correspondent, BBC News website
Online virtual worlds could soon be accessible to blind people thanks to research by students at IBM in Ireland.
IBM is establishing a presence in virtual worlds
Some estimates predict that 80% of active internet users will be using a virtual world in four years' time.
The company said that it is keen to ensure that blind people are not excluded from an environment that sighted people will take for granted.
The students have designed an audio equivalent of the virtual world using 3D sound to create a sense of space.
They were working as part of the company's Extreme Blue research initiative which brings groups of students together for 12 weeks to solve problem set by senior researchers.
The project - called Accessibility In Virtual Worlds - is what the company describes as "a proof of concept" at this stage, but it will be passed on to IBM's Human Ability and Accessibility Centre in Texas for further development.
For their work the Irish team decided to use the Active Worlds online environment rather than the more popular Second Life (which has almost 9.5m accounts) because it allowed them more flexibility.
Active Worlds is a collection of user-made virtual worlds that people can visit via a web browser plug-in. Like many other virtual spaces they let people make many of the artefacts, including buildings, found in them.
The research team exploited this ability to tinker with objects in the online world to make it more hospitable to the blind.
"When the user comes into the world, the items are described as well as their positions," explained Colm O'Brien, one of the team of four researchers who worked on the project.
"There is also sound attached - for example, if there's a tree nearby you will hear a rustling of leaves," said Mr O'Brien.
The work also developed tools which uses text to speech software that reads out any chat from fellow avatars in the virtual world that appears in a text box.
Characters in the virtual world can have a "sonar" attached to them so that the user gets audible cues to alert them to when they are approaching, from which direction and how near they are.
A number of blind mentors have given advice and feedback to the team - one in IBM's Dublin lab and two based at IBM's research centre in Texas.
The students have also liaised with the National Council for the Blind of Ireland on their work.
As well as proving that the idea is feasible, the team has made a number of recommendations about accessibility standards for virtual worlds which should help the developers of the future.
"IBM believes that virtual worlds are going to be the next big evolution of the web and if this happens...it's not right for blind people to be missing out on what the rest of us have available," said Mr O'Brien