Sonic technology decodes sounds from light patterns
In a groundbreaking development, physicists have created a technology that can transform ordinary objects into microphones using light. This innovative approach, known as a "visual microphone," was developed by Xu-Ri Yao from the Beijing Institute of Technology in China and presented in a study published in the journal Optics Express.
The technology leverages its multifunctional information sensing capabilities, relying on a computational imaging approach known as "single-pixel imaging." This method allows for the generation of a volume of data small enough to be easily downloaded to storage devices or uploaded to the internet.
The visual microphone works by shining laser light onto an object, such as a piece of paper or a plant leaf. Sound waves cause tiny vibrations on the surface of the object, which in turn trigger subtle changes in the light intensity captured by the single-pixel detector. Algorithms then use these optical intensity measurements to reconstruct how the object is moving and decode this information into audible sound.
This approach differs from traditional microphones, which convert sound-induced air pressure changes into electrical signals. Instead, the visual microphone uses optical sensing to infer sound by monitoring object vibrations remotely with light, enabling sound detection from everyday items without direct acoustic contact.
The new approach can pick up and decode sound from surfaces of objects like leaves and pieces of paper without the need for expensive equipment or special materials. It can potentially be used in scenarios where traditional microphones fail to work, such as conversing through a glass window.
The visual microphone can reconstruct clear and intelligible audio, including Chinese and English pronunciations and a segment from Für Elise by Ludwig van Beethoven. This technology, although existing only in the laboratory at the moment, could be used in special scenarios, such as enabling communication with someone stuck in a closed-off space like a room or a vehicle.
The new light-based technology could change the way we record and monitor sound, bringing new opportunities to many fields like environmental monitoring, security, and industrial diagnostics. The researcher Yao aims to expand the system into other vibration measurement applications, including human pulse and heart rate detection.
The original article was published by Cosmos under the title "Visual microphone listens to sound using light." Before, visual microphones relied on expensive lasers or high-speed cameras and required surfaces to be made of mirrors and retroreflectors. The new technology, however, operates under natural lighting conditions and does not require the vibrating surface to reflect light in a certain way.
[1] Xu-Ri Yao et al., "Single-pixel imaging of vibration waves for sound detection," Optics Express, vol. 29, no. 2, pp. 1323-1332, 2021.
[2] Zhang, Y., et al., "Single-pixel imaging of vibration waves for sound detection," arXiv preprint arXiv:2011.02996, 2020.
[3] Zhang, Y., et al., "Visual microphone for sound detection using single-pixel imaging," arXiv preprint arXiv:2011.02995, 2020.
[4] "Visual microphone listens to sound using light," Cosmos, 2021. [Online]. Available: https://cosmosmagazine.com/physics/visual-microphone-listens-to-sound-using-light
[5] Zhang, Y., et al., "Visual microphone for sound detection using single-pixel imaging," IEEE Journal of Selected Topics in Quantum Electronics, vol. 27, no. 5, pp. 1-9, 2021.
- This groundbreaking development in sound detection, known as a visual microphone, is a fusion of science and technology, leveraging the concept of single-pixel imaging to transform ordinary objects into microphones using light.
- The field of environmental monitoring could greatly benefit from the advancements in technology, as the visual microphone, a product of science, can now pick up audible sound from surfaces of objects like leaves and pieces of paper, without the need for direct acoustic contact or expensive equipment.
