Biomedical subjects

L Neovius

Publications and source records attributed to L Neovius.

4 recordsLinked to original sources

PubMed1999

Monitoring the environment: sound localization equipment for deaf-blind people.

The problems that deaf-blind subjects have with monitoring the environment and the strategies they use were identified using structured interviews. The use of the vibratory sense did not appear to be highly developed, but some individuals indicated that it has great potential. We describe here the design of a computerized laboratory device for sound localization, based on a three-microphone system with a cross correlation algorithm. It was found to have reasonable precision and sufficient reliability to allow the detection and localization of a person approaching a deaf-blind subject in an ordinary room. The next step is to miniaturize the equipment and build a portable prototype.

Algorithms↗

PubMed1981

A multi-language, portable text-to-speech system for the disabled.

Previous experience with speech output aids for blind and non-vocal persons has shown great promise. The need for individual adjustments and the relatively small market, makes flexible, programmable aids necessary. A modular microprocessor text-to-speech system has been developed that is portable and battery-operated. This prototype has been adjusted to several different users. Programs for different languages have been developed. Connection of text sources is simplified by standardized interfaces. One special attachment is a 500 symbol Blissymbol board and a related Bliss-to-speech program that transforms the symbol string to well formed sentences.

Blindness↗

PubMedDate not supplied

Vibratory-coded directional analysis: evaluation of a three-microphone/four-vibrator DSP system.

A sound localization aid based on eyeglasses with three microphones and four vibrators was tested in a sound-treated acoustic test room and in an ordinary office. A digital signal-processing algorithm provided a determination of the source angle, which was transformed into eight vibrator codes each corresponding to a 45 degrees sector. The instrument was tested on nine deaf and three deaf-blind individuals. The results show an average hit rate of about 80% in a sound-treated room with 100% for the front 135 degrees sector. The results in a realistic communication situation in an ordinary office room were 70% correct based on single presentations and 95% correct when more realistic criteria for an adequate reaction were used. Ten of the twelve subjects were interested in participating in field tests using a planned miniaturized version.

Adult↗

PubMedDate not supplied

A three-microphone system for real-time directional analysis: toward a device for environmental monitoring in deaf-blind.

Sound localization is a problem for the hearing impaired, deaf, and deaf-blind. A laboratory prototype of a three-microphone digital system for real-time directional analysis of sound sources that is mounted on eyeglasses has been developed. A cross-correlation algorithm is used for determinations of time and phase differences between the three microphone signals. The equipment was evaluated in a sound-treated test room with noise and speech stimuli from 12 different directions. It has an adequate precision (within approximately +/- 10 degrees) for speech and noise bursts in the frequency range 0.5-4 kHz, and for testing with words in a sound field the error percentage is very close to 0 at 0-degrees azimuth. The robustness of the algorithm in terms of signal-to-noise ratio is documented and reaches about +8 dB in different directions for speech and up to 0 dB for noise bursts. It is concluded that the construction of a robust system for directional analysis with sufficient efficiency for further experiments has been achieved.

Algorithms↗