Text-to-Speech Synthesis To Improve TV Accessibility
Kate Knill
SLTC Newsletter, July 2010
In the UK 90% of blind and partially sighted people "watch" TV every two days. The current interfaces available for digital TVs and set-top boxes limit their user experience as 60% cannot use on-screen menu navigation. This article discusses ongoing efforts in the digital television industry to improve accessibility by using text-to-speech synthesis to voice the digital TV information.
It may appear slightly contradictory but a survey by the Royal National Institute for the Blind (RNIB) has shown that 75% of blind and partially sighted people “watch” TV every day with 90% watching every two days [1]. However the current interfaces available through digital TVs and set-top boxes (TVs will be used to refer to digital TVs, connected TVs and set-top boxes in the rest of this article) limits their user experience. 60% cannot use on-screen menu navigation so they are restricted to using up/down channel buttons or remembering the channel number to navigate. Not the quickest or most convenient of methods when the number of channels is in the tens and hundreds! The number of people with partial sight and blindness in the UK is estimated to be between 1.8 [2] and 2.7 million [3] so there are a substantial number of people whose viewing experience could be enhanced. And the problem will continue to grow – projections show that this figure will grow to approximately 3.99 million by 2050.
A number of partially sighted and blind people access electronic programme guides (EPG) today through their PCs where they have access to text-to-speech synthesis (TTS) to voice the information. Television industry groups in the UK and Europe are working on adding the same functionality to TVs. With TTS, many more viewers will be able to find out more about the programme they’re watching, what’s on now and next, control their digital video recording etc. 88% of those questioned by the RNIB said they would use an audible guide if available [1].
The industry association for digital television in the UK, the Digital TV Group (DTG), published a white paper on implementation guidelines and recommendations for TTS for TVs in December 2009 [4]. Although the DTG’s remit is for the UK, the proposals should be applicable to many countries. Two approaches to provide TTS are envisaged: embedded in the TV; a separate standalone unit. The DTG white paper attempts, from a user requirements perspective, to outline the minimum requirements each TTS enabled product should adhere to, e.g. the logical channel/service number should be spoken. Implementation guidance is given on what type of text should be spoken and when for both static data such as the service name e.g. “BBC1” and dynamic data such as the current programme information e.g. “3 ITV1 Coronation Street 7.30-8pm”. The interface and protocol between the external TTS box and the TV is being considered by groups such as DIGITALEUROPE, the European digital economy advocacy group for information technology, consumer electronics and telecommunications.
Hopefully we should start seeing TTS available as an option in set-top boxes and TVs within the next couple of years.
References
- Research into Digital Television: Analysis of 2007 survey on the user habits and preferences from Blind and Partially Sighted People, L.Petré, E.Chandler, RNIB Report, ISBN: 978 1 4445 0033 2, July 2009.
- Future Sight Loss UK (1): The economic impact of partial sight and blindness in the UK adult population, Access Economics Pty Ltd, RNIB Report, July 2009.
- Provision of Access Services, Research Study conducted for Ofcom, March 2006.
- DTG Usability Text To Speech Subgroup White Paper: Implementation Guidelines and Recommendations for Text-to-Speech v.1.4, DTG, December 2009.
Acknowledgements and more information
Thanks to Raheel Mallick and Edward Chandler of the RNIB for providing input to this article.
Kate Knill is Assistant Managing Director and Speech Technology Group Leader of Toshiba's Cambridge Research Lab. Her interests are speech recognition and speech synthesis. Email: kate.knill@crl.toshiba.co.uk.