How is sound recorded in videos?
When we talk to our friends in a room, they can hear us clearly. But what if we talk to them in a noisy market? They won’t be able to hear us because of all the other noises. You would have to be extra loud! Microphones work the same way. Sometimes there’s so much noise that we aren’t able to hear any sound clearly. It just sounds like a mix of noises. Whenever we record a video, the camera captures moving objects that we can see. And the microphone captures the sound. So we can say that cameras are like eyes, and microphones are like ears.
What’s wrong with how microphones record sounds?
Microphones are used to record sounds. But they pick up many extra sounds too. This makes it hard to hear the sound we want. If only there was a camera that could see and hear as well. That would solve the problem. But is this possible?
A camera that can record sounds without a microphone, what!?
Yes! Students from Carnegie Mellon University in the USA have really made this. They have made a camera that can see sound. (yes, see, not hear!). Not only can this camera capture sound, but the sound is crystal-clear! That’s incredible!
How does one “see” sound?
Every sound in the world makes a vibration. The vibrations move from the sound-making object to our ears, travelling through the air. And it happens really fast! That’s how we can hear sounds.
The new CMU camera can see very clearly. It records the vibrations that come from sounds. The camera then turns these vibrations into sounds.
These cameras could be very useful. They could be used in factories. The camera would be able to hear every machine. It could even hear which machine isn’t working right and needs repairs.
Uh-oh. Can this camera hear humans too?
Yes! As long as this camera can see us, it can hear us! That means this camera could hear everything we say, even if we whisper! Do you think this camera can be used to spy on people?