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Web Posted on: August 4, 1998


The public Swedish video relay service.
A service in line with the TIDE HEART study recommendations

Gunnar Hellström
National Post and Telecom Agency
Box 5398, S-102 49
Stockholm, Sweden tel: +46 8 678 55 00
fax: + 46 8 678 55 05
email:gunnar.hellstrom@omnitor.se

1. Summary

The Swedish National Post and Telecom Agency has started a provisional video relay service for translation between sign language and spoken language in the telephone.

By using very carefully selected videophones with best quality for signing on ISDN connections, the service can provide affordable services of very high user value. The service offers an easy-to-use telecommunications link between deaf and hearing people providing a step closer to equal opportunities to communication for all.



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2. Introduction

The TIDE HEART Line F study investigated what technical and service developments were needed to get closer to equal opportunities in personal communication. One recommendation in the final reports in 1995 was that services should be developed for relaying between sign language in the videophone and spoken language in the voice telephone. This is an important requirement to open for more efficient distant communication between hearing and deaf people.

The Swedish National Post and Telecom Agency has acted according to this recommendation and started a provisional video relay service open to the public from February 1997.

By using carefully selected videophones with best available quality for signing, the service can give high user value at an acceptable cost. This presentation gives information from the first year of the service, reporting on the experience from the users and the service provider.



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3. The National Post and Telecom Agency

The National Post and Telecom Agency is the national telecom regulating authority in Sweden. One of the responsibilities is to make sure that services of importance for people with disabilities are made available. Alf Tengström is responsible for these activities and can provide further general information. The main method to achieve this goal is through procurement. Experience shows that this method gives good value for the resources available in society for these purposes. In this case the trial service was procured in competition, and Örebro Interpreter Centre got the task to run the trial service. Gunnar Hellström, technical advisor to the trial project, can provide further technical information.



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4. The services

The goal of the service is to provide deaf people with better opportunities to telecommunication services by allowing them to use the Swedish Sign Language in telecommunication also when communicating with hearing people.

By providing connection to a centre with sign language interpreters, the users can request calls to be relayed between signing in the videophone and using voice in a voice telephone.

During the trial, the service has not been charged to the user.

During the trial, distant interpreter services have also been provided. This service is used by deaf and hearing people in the same location getting access to an interpreter through a videophone call. It is only offered for small meetings. Earlier experience tells that large meetings tend to become unmanageable for distant interpretation.

The service is currently open Monday through Friday 8 a.m. to 8 p.m., serving around 60 user terminals all around Sweden doing around 400 calls per month. A group of interpreters are now experienced "video interpreters" and have helped formulating a code of practice for smooth handling of the calls. The Swedish Handicap Institute provided support during the initial service trial, organising a reference group and collecting user views of the service.

The principle of the video relay service. A videophone user use sign language with an interpreter and the interpreter translates to a voice call to the voice telephone user.

Figure 1: The video relay service relaying a call between a videophone and a voice phone.



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5. The terminals

The requirements on videophones to perform well for sign language are to provide high picture update rates and reasonably sharp images. With a new video-coding standard, acceptable quality can be achieved on single ISDN connections using two channels together giving 128 kbit/s bandwidth. The interpreter terminals were selected using a quality evaluation method developed in a research project by the Swedish Association of the Deaf. The method extracts quality factors in a way that is related to sign language so that they can be enumerated and compared.

Experience shows that the quality factor where the products have most trouble fulfilling the needs is regarding the picture update rate with signing in the picture. Often this figure is much lower than the figure used in product brochures usually indicating the highest possible picture rate achieved in a completely still view. It is observed that real usability starts at 12 pictures per second and increases up to 25 pictures per second when signing. Lower values give jerky motion reproduction and loss of language contents.

The same resolution as used in consumer video recording is found sufficient but important, reproducing 352 points horizontally. It has been found possible to use a lower resolution, reproducing a coarser image with only 176 points horizontally. That resolution introduces some uncertainty and irritation to the users, and is not normally used in the Swedish service.

5.1 Video delay - the next quality bottleneck

One important factor when video communication is used for conversation is the delay of the picture from the camera to the screen of the other terminal. Today, with current ISDN terminals the value is usually around 0.7 seconds. It is a bit annoying to be forced to wait 1.4 seconds for a reaction from the other end. The interaction pattern of people is influenced by this delay. It is likely that in the future, Internet and other packet transmission methods will be used to a high degree for video communication. Even if these networks will provide high bandwidth, they introduce a risk of longer and annoying delays.

5.2 User's terminals and interpreter's terminals are of equal importance for the service quality.

The same high video quality requirements must be put on the user's terminals as on the interpreter's terminals. A key factor for communication is also that they are made according to the same communication standards. In practise, most user terminals currently come from projects where the same quality evaluation method has been applied as for the relay service terminals.

5.3 Poor quality primarily affects transmission

A poor quality user terminal may display the interpreter with good quality but transmit a jerky and fuzzy picture of the user to the interpreter, making it tiresome and hard to work as an interpreter. Therefore, even if seldom executed, the interpreters are given the authority to refuse relaying calls with too low video quality.



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6. The user reactions

The users claim that the video relay service is of high importance for them. The flow of the dialogue in sign language is much more rapid and easy compared to the written language in the text relay they were used to before.



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6.1 Importance of using sign language in telephone conversations.

It is reported very important for the users to be able to use their first language, the Swedish sign language, in telephone conversations. The misunderstandings decrease, the speed of conversation increases, the flow of conversation is natural. It is easier to remember what you have discussed in your first language. Especially at work, the video relay service has proven to give deaf people high efficiency and self-esteem. Also hearing people using the service through the voice phone have said that they are astonished how easily and rapidly the dialogue flows.



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7. Telecom services

A basic set of telecom services is needed in the video relay service. The Interpreters should be reached on one number only for video calls and one number for voice calls. During the trial period, no call charges are made. Two free-phone group numbers are used, one in ISDN for the video calls and one in the analogue network for the voice calls. They are arranged in such a way that the interpreter services has control over the call distribution. Thus they can direct the calls to different interpreters working in the service from a small number of sites in Sweden with the proper equipment.



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8. The future

The report after the first nine months of trial production was positive and indicated that there are many reasons for making the service permanent. The users stress the importance to keep the quality in sign language communication high, and recent product offerings indicate encouraging improvements in both sign language performance and price. The products to use still have to be selected very carefully, verifying the sign language performance.



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8.1 Will the video relay replace the text relay service?

Sweden has a well-established text relay service open 24 hours a day. All users who need a text telephone have one.

The video relay service serves in many cases the same users as the text relay service. Therefore it is expected that, eventually, the sum of the load on the two services will be approximately constant. Initially however, we have observed that the relay service is used with a higher frequency and therefore creates a higher total load.

It is not expected that the video relay will totally replace the text relay. There are many text telephone users who are not sign language users, and there are many situations where a text telephone may be available but not a videophone.

8.2 Text conversation - a valuable add on.

When asked what improvements the users felt to be of importance, one common response was to have an opportunity to occasionally use text during the video call. It is expected that a text conversation feature will improve the transfer of telephone numbers. Until February 1998 there has not been any international standard available for this function, and therefore it has not been possible to provide it. Now, standards are in place, and it is possible to fulfil this user requirement.

8.3 Continued service in planning.

The number of videophone users in Sweden is now enough to occupy three interpreters in rush hours. An increase is expected during 1998, when the first user terminals provided as rehabilitation aids on a regular basis are distributed for both the working place and at home.

The National Post and Telecom Agency now investigates the possibility to continue to offer video relay service to the Swedish users.



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9. Conclusion

The need for a public video relay service identified in the HEART study has now been turned into a reality. The service is proven to be an important step towards equal opportunities to telecommunications for deaf people. The reports from the trial service in Sweden clearly show that efficiency and self esteem is increased in an important way. A continued service is expected to become increasingly popular and important as the number of videophones used for sign language is rapidly increasing.



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Literature:

HEART Line F F.1 Report 3. Review of the current situation and assessment of future prospects of rehabilitation technology. (1995) Hellström, Lindström, Olsson, Stephanidis, Emiliani. The Swedish Handicap Institute 1995.

Introducing New Blood , An overview of the Heart Line F report (1995) The Swedish Handicap Institute 1995. ISBN 91-88 336 53-0

Quality measurement on Video Communication for Sign Language (1997) Hellström, HFT'97 Proceedings pp217-224. ISBN 82-994236-0-0

Videotelephony and Relay service for sign language (1997) Delvert, HFT´97 Proceedings pp 227-231. ISBN 82-994236-0-0

 



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