Wearable sensor can accurately recognise your voice

Scientists have developed a flexible and wearable sensor that can precisely recognise voice through vibration of the neck skin.

A voice-recognition feature can be easily found on mobile phones these days.

However, we often experience an incident where a speech recognition application is activated in the middle of a meeting or a conversation in the office.

Sometimes, it is not activated at all regardless of numbers of times we call out the application.

This is because a mobile phone uses a microphone which detects sound pressure to recognize voice, and it is easily affected by surrounding noise and other obstacles.

Researchers from Pohang University of Science and Technology in South Korea have successfully developed a flexible and wearable vibration responsive sensor.

When the sensor is attached to a neck, it can precisely recognise voice through vibration of the neck skin and is not affected by ambient noise or the volume of sound.

The conventional vibration sensors recognise voice through air vibration and the sensitivity decreases due to mechanical resonance and damping effect, therefore are not capable of measuring voices quantitatively.

So, ambient sound or obstacles such as mouth mask can affect its accuracy of voice recognition and it cannot be used for security authentication.

Researchers showed that the voice pressure is proportional to the acceleration of neck skin vibration at various sound pressure levels from 40 to 70 dBSPL and they developed a vibration sensor utilising the acceleration of skin vibration.

The device, which is consisted of an ultrathin polymer film and a diaphragm with tiny holes, can sense voices quantitively by measuring the acceleration of skin vibration.

They also successfully exhibited that the device can accurately recognise voice without vibrational distortion even in the noisy environment and at a very low voice volume with a mouth mask worn.

The research can be further extended to various voice-recognition applications such as an electronic skin, human-machine interface, wearable vocal healthcare monitoring device.

"This research is very meaningful in a way that it developed a new voice-recognition system which can quantitively sense and analyze voice and is not affected by the surroundings," said Kilwon Cho, a professor at POSTECH.

"It took a step forward from the conventional voice-recognition system that could only recognise voice qualitatively," Cho said.