Helium speech unscramblers--A critical review of the state of the art (original) (raw)
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Breathing noise elimination in through-water speech communication between divers
The Journal of the Acoustical Society of America, 2007
Breathing noise and bubble noise are the main factors affecting the subjective quality of through-water speech signals in communications between divers wearing full-face masks or aural-nasal masks. Only breathing noise is considered here, which can be gated out by applying a combination of zero-crossing detection and energy measurements to noisy speech signals above predetermined threshold values. The signals are picked up by a microphone placed close to the diver's mouth in the air cavity of the mask. Results were obtained during diving trials with four different types of masks.
Speech Communication in Diving Masks. II. Psychoacoustic and Supplementary Tests
The Journal of the Acoustical Society of America, 1971
As work progressed from the physical measurements reported in Part I [J. Acoust. Soc. Amer. 50, 1-9 (1971)-] to psychoacoustic testing, the gradient microphone proved not merely to perform somewhat better than the pressure microphone in diving-mask cavities, but to be essentially insensitive to cavity acoustics. With the gradient microphone, no optimum cavity dimensions were found, and standing-wave absorption within the cavity became unnecessary. These results were confirmed by SOhograms and by response measurements with an artificial vocal tract.
Use of speech production repair strategies to improve diver communication
Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc, 2003
The purpose of this investigation was to determine if speech intelligibility improved when divers made specific modifications to their speaking patterns while in a hyperbaric helium-oxygen (heliox) environment. Divers were trained to produce a variety of sentences using speech with three types of alterations: (1) slowed rate, (2) increased loudness, and (3) a combination of slightly slowed rate, a minimal increase in loudness, increased pause time, and greater mouth opening (composite strategy). Both diver and non-diver listeners judged these sentences for intelligibility. In addition, acoustic analysis of the cues for the identification of voicing, place, and manner of articulation was conducted to determine if such cues might become more audible in the speech signal when repair strategies were used. Both perceptual and acoustic results showed the composite method to be the best for natural-sounding, intelligible speech. It had the effect of slowing rate and increasing loudness jus...
Detecting respiratory noises of diver equipped with rebreather in water
Proceedings of Meetings on Acoustics, 2016
The aim is an analysis of respiratory noises of diver equipped with a closed circuit breathing apparatus (rebreather). The noises were recorded in the shallow-water bay near the suit of the diver equipped with F.R.O.G.S. (Full Range Oxygen Gas System, http://www.aqualung.com) rebreather and at the distance of 3 m (in rest) by bottom located omnidirectional hydrophones. Energy receivers were used for detecting the noise signals in frequency bands of 30-300 Hz. Both hydrophone responses contained evident quasiperiodic components induced by amplitude modulation of wideband respiratory noises with the rate of breathing maneuvers. The breathing rate estimated by means of spectral transform of the envelope was about 0.3 Hz for inspirations and 0.6 Hz for the whole respiratory cycle. The quasi-periodic components with closely located frequencies were also found when the diver moved on fins around the hydrophones. The breathing rate index represents human individual physiologic status. Thus the procedure is pertinent for distant monitoring the breathing rate of submerged divers equipped with F.R.O.G.S. rebreathers as well as with scuba apparatus.
Connection between body condition and speech parameters – especially in the case of hypoxia
This paper deals with a special area of cognitive infocommunications, in which the goal is to determine the cogni-tive state of subjects through the measurement of speech parameters. Human speech is a complex function that consists of cogni-tive and organic relationships. The state of the brain regions responsible for producing speech has a great influence on speech ability, and this is detected by measuring the acoustic parameters of the generated voice signal. Improper functioning of these organs results in noticeable differences in speech. In the normal body condition the articulation movement between two speech sounds and the associated spectral change occur at a specific rate. If the speech is superficial, for some reason the transition between the sounds – the rate of the change – is slow compared to normal articulated speech. The transient parts can be diminished or absent. In this paper, we investigate the ratio of the duration of the transient parts and the duration of the whole speech expression of the crew members during their stay at Concordia Research station, in Antarctica. The evaluation of the data shows that the transient-speech segment ratio decreased after the crew members arrived at the research station. The restoration of normal conditions lasted for weeks, but the recovery time is strongly person dependent. Further investigation is necessary, but the results of the paper can be seen as a new CogInfoCom channel that can be used to make an earlier diagnosis of certain health problems.
Underwater voice communications using digital techniques
Le Journal de Physique IV, 1994
A digital signal processor (DSP) based voice communication system for divers with a 2400 bitls transmission rate is described. Each speech signal frame is analysed using linear predictive coding (LPC) and the essential parameters such as amplitude, pitch period and digital filter coefficients are extracted. These parameters are transmitted through a water channel at a rate of 2400 bitls by employing digital pulse position.modulation (DPPM).
Cognitive technologies, 2023
This chapter provides an in-depth account of current research activities and applications in the field of Speech Technology (ST). It discusses technical, scientific, commercial and societal aspects in various ST sub-fields and relates ST to the wider areas of Natural Language Processing and Artificial Intelligence. Furthermore, it outlines breakthroughs needed, main technology visions and provides an outlook towards 2030 as well as a broad view of how ST may fit into and contribute to a wider vision of Deep Natural Language Understanding and Digital Language Equality in Europe. The chapter integrates the views of several companies and institutions involved in research and commercial application of ST. 1
Variability of SCUBA diver's acoustic emission
Optics and Photonics in Global Homeland Security IV, 2008
Knowledge of the variability of the acoustic emission characteristics from SCUBA divers is critically important for designing and operating a passive acoustic SCUBA characterization system. Using modeling and experimental measurements in a controlled environment, we identified key source factors influencing the variability of the acoustic emission parameters including Source Band Level (SBL), Spectral Power Density (SPD), and breathing periodicity or emission modulation frequency. The key factors are: equipment, specifically, the design of the first stage (high pressure) regulator and its service life; diver's experience and training; and, finally, operating conditions of the equipment and diver, i.e. tank air pressure and the diver's motion activity. We found, for example, that the SBL could vary as much as 16 dB depending on the equipment used and up to 15 dB depending on the diver's intensity of motion.
Variability of SCUBA diver's acoustic emission
2008
Knowledge of the variability of the acoustic emission characteristics from SCUBA divers is critically important for designing and operating a passive acoustic SCUBA characterization system. Using modeling and experimental measurements in a controlled environment, we identified key source factors influencing the variability of the acoustic emission parameters including Source Band Level (SBL), Spectral Power Density (SPD), and breathing periodicity or emission modulation frequency. The key factors are: equipment, specifically, the design of the first stage (high pressure) regulator and its service life; diver's experience and training; and, finally, operating conditions of the equipment and diver, i.e. tank air pressure and the diver's motion activity. We found, for example, that the SBL could vary as much as 16 dB depending on the equipment used and up to 15 dB depending on the diver's intensity of motion.