Researchers Develop a Low-Cost Visual Microphone

alternative_right shares a report from Phys.org: Researchers have created a microphone that listens with light instead of sound. Unlike traditional microphones, this visual microphone captures tiny vibrations on the surfaces of objects caused by sound waves and turns them into audible signals. In the journal Optics Express, the researchers describe the new approach, which applies single-pixel imaging to sound detection for the first time. Using an optical setup without any expensive components, they demonstrate that the technique can recover sound by using the vibrations on the surfaces of everyday objects such as leaves and pieces of paper.

To demonstrate the new visual microphone, the researchers tested its ability to reconstruct Chinese and English pronunciations of numbers as well as a segment from Beethoven's Fur Elise. They used a paper card and a leaf as vibration targets, placing them 0.5 meters away from the objects while a nearby speaker played the audio. The system was able to successfully reconstruct clear and intelligible audio, with the paper card producing better results than the leaf. Low-frequency sounds (1 kHz) showed slight distortion that improved when a signal processing filter was applied. Tests of the system's data rate showed it produced 4 MB/s, a rate sufficiently low to minimize storage demands and allow for long-term recording. 'Currently, this technology still only exists in the laboratory and can be used in special scenarios where traditional microphones fail to work,' said research team leader Xu-Ri Yao from Beijing Institute of Technology in China. 'We aim to expand the system into other vibration measurement applications, including human pulse and heart rate detection, leveraging its multifunctional information sensing capabilities.'

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