Researchers have developed an optical microphone that uses cameras to record the vibrations of objects. This system enables the sound of a single instrument in an orchestra to be isolated, eliminating any influence of acoustics in place.
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Isolating the sound of a single instrument in an orchestra, or recording music played without ambient noise, is a very complex task, even with the best microphones. to solve this problem , researchers from Carnegie Mellon University in the United States microphone Optics capable of seeing percussion instrument of an object, thus capturing the sound generated by only one device.
Such a system that only uses the camera would need to zoom in on an object to be able to capture something small sound-induced vibrationsIt must be very high Speed To detect the frequency of this movements. This type of device would be very expensive and complicated to set up.
Laser and two consumable cameras
Instead, the researchers found a solution by using much cheaper and more readily available hardware. The optical microphone is based on a laser Which refers to a surface, such as a tool. When the laser is reflected, the body shaking Create Peelor spot, any pattern that can be recorded with cameras.
Their system then uses two cameras that record just 60 frames per second. This may sound insufficient for sounds with possible frequencies up to 20000 Hz. The trick is to combine images from two different sources.
Explanation and presentation of the optical microphone. In English only, activate automatic translation of translations. © Mark Shenin
Two cameras recording at 63 kHz
The first camera contains a file shutter in general (or universal shutter) which records the scene in a single take. The second uses a rolling shutter (or rolling shutter) which saves the image line by line in a file sensor With a very slight delay. This delay, which can cause image distortions of a moving object, is used here for information on high-frequency vibrations. Thus, the lines are recorded at a frequency of 63000 hertz.
The researchers then used an algorithm to stitch the two images together and recreate the sound. Their system runs directly on the machine, like A guitar Or the violin, and even other things that vibrate with it echoLike a box of potato chips in front of a loudspeaker. It is even able to compensate for the movements of the musician.
With this system, sound engineers can track each instrument individually in a band or orchestra, withoutconfusion others. It completely removes the effect of acoustics from the recording room by effective removal every echo. The system can also be used to monitor every machine in a noisy factory to determine when one needs maintenance.
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