Sound Source Localization – Acoustic Beamforming Array / Acoustic Camera
Unlike visible light, human can hear sound from all directions. This sometimes causes human to have difficulties in localizing sound source, especially if there are many sound sources close to each other, and it gets harder when the room is reflective because the sound bounces from surface to surface. To overcome this problem, acoustic beamforming arrays are designed. Acoustic beamforming array, or more popularly known as acoustic camera, could help the user to visualize sound sources in certain frequency and sound levels.
The technology that make this possible is beamforming system. In an acoustic camera, there are a number microphones. From one sound source, the sound will arrive in different times to each microphone depending on the relative position of the sound source to each microphone. This condition allows acoustic camera to steer the beam to a particular position so that the sound source in that direction is in much higher level than the other directions. Acoustic camera has the ability to scan a plane by steering the beam across the area of a plane, so that it can decide which direction gives the camera most acoustic energy, and therefore the dominant sound source is known.
An acoustic camera could be used in many different applications. Here are some example:
1. Building acoustics:
Suppose there are sound leakage in a partition or a facade of a building. A small leakage can cause a significant reduction in sound insulating performance of a partition. To be able to fix this problem effective and efficiently, we need to know where is the leakage. One of the fastest way is to have a sound source in one side of the partition (source room), and placing an acoustic camera in the receiving room. That way, the leakage in the partition can be located. Case studies can be found in these links:
2. Environmental noise:
Noise control at source is most effective when the most dominant noise source’s sound power is reduced – because of it’s logarithmic property. Therefore, acoustic camera is a helpful tool to be able to find the most dominant source in a complex group of sound sources. Here is a link to a case study
3. Industrial applications:
As the demand for low-noise products raises, some industries has put acoustic cameras into their research and production processes. For example, automotive industries who do research in reducing noise in their products. Acoustic camera is also useful for quality control. When there are products that are found to be noisy, the products can be inspected further to know which part creates the noise and therefore fails the quality control processes. Here is a case study.
Geonoise uses and provide acoustic camera from Norsonic. For further information, click here
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