Users can read the image's lips and listen on the phone

European scientists have developed software to help people with hearing problems have conversations on the telephone.

Millions of people with hearing problems can get by in face to face situations by reading lips. However, the skill is of little use when it comes to talking on the phone.

Now scientists in the UK, Holland and Sweden are putting the finishing touches to new technology, known as Synface, which could change all that.

Animated conversation

The technology works by turning human speech at one end of the phone line into a speaking, moving artificial face at the other end.

Users attach their normal telephone handset to a computer and speak into it as normal. They can also listen as normal.

The images mimic the movements of people speaking

But in an effort to boost their chances of hearing what is being said, they can also lip-read.

A 3-D animated face on the computer screen recreates the expressions and the movements of the mouth and tongue associated with speech.

This enables users to read the lips while they also try to listen to what is being said.

Unlike videophones, the other user does not need to have their phone attached to a computer and can use their existing telephone.

Early trials have shown that the technology is effective. Larger scale trials are planned later this year according to Dr Jonas Beskow of Sweden's Royal Institute of Technology and one of those involved in the project.

"We plan to start testing this technology with hearing impaired users," he told BBC News Online.

"After that, in about one year, we hope to have a prototype ready which would enable us to take the first steps towards making this technology available commercially."

UK trials

According to the Royal National Institute for Deaf People, trials will also be carried out on English language versions of the technology in the UK.

Neil Thomas of the RNID said: "This technology is really about offering additional support to people who are hard of hearing.

"There is no expectation that it will be used by people who are profoundly deaf," he told BBC News Online.