Lip-reading mobile phone on way

Researchers are developing a lip-reading mobile phone that could end the irritation of having to listen to other people's conversations.

A Japanese firm is working on a handset that will convert silently mouthed words into speech or text.

The early prototype from NTT DoCoMo works out which words are being said by detecting tiny electrical signals sent by muscles around the mouth.

The signals are converted into spoken words by a speech synthesiser, or into text for a text message or email.

Engineers are still developing the lip-reading software, New Scientist magazine says.

A test model can now recognise vowels with an "acceptable error rate". The team is now working on the tougher task of recognising consonants.

Lip-reading accuracy could be boosted using the cameras that will be common in new generation 3G phones.

In Japan, mobiles are banned on some public transport networks and in many other places etiquette requires that people using a phone hold a hand discreetly over their mouth.

The technology, which should be ready for the marketplace in about five years, is also expected to help people who have lost their voice.