A new device developed at the Beijing Institute of Technology can reconstruct sound by detecting it with light. This system, called a “visual microphone,” enables sound recording by analyzing microscopic vibrations on surfaces.
A microphone capable of listening to sound with light has been developed.
The research used a single light detector and a spatial light modulator to detect minute variations in light reflected from an object’s surface. This technology allows sound to be successfully deciphered from a distance using only light, without the need for physical sound transmission.
The system operates without the need for expensive equipment such as lasers and high-speed cameras. In the research, simple objects such as a leaf and a paper card were used to reflect the vibrations created when sound hits the surface. Speech and musical sounds were played from half a meter away.
In the tests, both Chinese and English numbers and Beethoven’s “Für Elise” were clearly reproduced. The paper card was observed to have better sound quality than the leaf. Low-frequency sounds (<1 kHz) were detected accurately, while some signal distortion occurred at higher frequencies. However, these distortions can be significantly eliminated with digital processing.
The technology is based on a single-pixel imaging technique. With this method, surface vibrations are detected as changes in light intensity. The incoming data is processed by algorithms and converted into audio signals.
The system’s low data production also facilitates long-term or continuous audio recording. Because it does not require a high data capacity, it offers a more cost-effective and efficient solution compared to traditional systems.
The visual microphone can operate in any environment where light can pass. Its ability to detect sounds through glass barriers allows the system to be used in scenarios where traditional microphones are inadequate.
Its potential applications are particularly promising in areas such as long-distance environmental monitoring, medical measurements, and communication through glass. It is also being considered as a solution in disaster areas or sensitive industrial environments where microphone placement is difficult.
The research is currently being conducted under laboratory conditions. Work is ongoing to make the system portable, with higher sensitivity and longer-range sensitivity. It’s stated that as the technology develops, it could offer new alternatives for medical applications such as remote heartbeat or pulse detection, or for rescue operations. The study was published in the journal Optics Express.
