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Super Sensear |
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A look at the stylish sound technology.
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Superman's super-hearing lets him hear a single cry for help over the noise of a busy city. Now an Aussie company has developed a hearing device that lets mere mortals do the same - the Sensear.
Noise-induced hearing loss (NIHL) is the world's most common occupational illness. It's difficult to avoid, because even though workers can wear ear protection in noisy environments, earmuffs block out speech as well as background noise. Communication is vital in industries such as mining, construction, manufacturing and entertainment, and workers often have to remove their hearing protection to speak in loud environments. This regular noise exposure damages their hearing, and NIHL costs the Australian economy alone billions of dollars each year.
That's where Sensear's hearing technology is aiming to make a difference. Sensear's ear-muff and iPod-style devices are able to detect and distinguish speech from other sounds, amplifying it while filtering out background noise. To separate speech from noise in real-time, the devices use an array of built-in microphones connected to a microprocessor running Sensear's advanced signal processing algorithms.
"We have developed a specific method of Voice Activity Detection that is more robust to loud and time varying background noise" said Professor Sven Nordholm, Sensear's Chief Technology Officer. "We look at short term and long term power estimates in different frequency bands, and we combine those estimates into one estimate to say, this is voice, this is noise. From that we do our processing depending on if we have noise or if we have voice."
The result is clear-sounding speech in high-noise environments, allowing workers to communicate without removing their hearing protection.
"There are other companies allowing voice communication while wearing hearing protection, but not in a high-noise setting" said Sven. "What they do is that they cut off the microphone when the noise level goes up, so you can't talk."
The technology has applications not only for hearing protection, but also as hearing assistance for people with moderate hearing loss who occasionally have trouble following voices in noisy environments. The Sensear devices have Bluetooth capability, allowing wearers to take mobile phone or two-way radio calls without removing their hearing protection.
In addition to allowing speech against constant background noise, the Sensear software can also cut down sudden big sounds, like a loud "bang", to safe levels while still allowing the user to hear a natural-sounding noise - an important safety consideration.
"We have built a detector that detects when we have large input signals, and then we limit the output while maintaining the waveform" said Sven. "So if you were to use a hammer, it still sounds like a hammer, but the volume is lower. You still want to be aware of the sounds you are making, because the characteristics of the sound give you important information about what you are doing."
The technology was originally developed by Professor Nordholm's team at the WATRI (Western Australian Telecommunications Research Institute), and Sensear Pty Ltd was formed to commercialise the technology. Many of the technical advances grew out of Professor Nordholm's research into solving problems with wireless technology. Since the wireless industry was in decline in Western Australia, they decided to turn their attention to the needs of other industries.
"We said maybe we should do something for the local industry here in Western Australia - mining was really picking up quickly here."
Sensear will appeal to markets far beyond West Australian mining - especially the iPod version, which may find use amongst nightclub and entertainment industry staff.
Just as Superman's super-senses always save Lois Lane in the comics, Sensear's real life super-smart sensing technology could soon save the hearing of workers world-wide.
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Sound levels are measured in decibels (dB). Normal breathing is about 10dB, a typical conversation is about 60 dB, and a factory can be over 80 dB. An increase of 3dB represents a doubling in the level of sound being measured.
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Long-term exposure to noise louder than 85dB is damaging to human hearing, and workplaces that reach this level of noise typically must require workers to wear hearing protection.
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The cells in the ear responsible for hearing are tiny hair cells located in the inner ear. These hair cells possess sensing organelles called stereocilia, which can be overstimulated and damaged by prolonged exposure to loud noise. Unfortunately in humans and other mammals, once destroyed, hair cells do not regenerate - that's why protecting your hearing in the first place is so important.
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