What is an Acoustic Camera and How does it work?

An acoustic camera is used to locate and characterize sound sources. It works by using beamforming to process signals from multiple microphones to determine the location and direction of a sound source. By doing so you can see where the noise is coming from. Acoustic cameras are used in various applications, including noise reduction, industrial inspection, and medical diagnosis.

Acoustic cameras offer several benefits over traditional sound source localization methods, such as sound level meters and human ears. They are more accurate and precise and can be used to localize sound sources in noisy environments or areas that are difficult or dangerous to access.

How does an acoustic camera work?

Compare your ears with a microphone. Sound travels via sound waves to your ears. When it first arrives at your right ear and later at your left ear, you can localize where the sound comes from. You need at least two ears to localize sound.

An acoustic camera is more precise than your ears. It has an array of 64 to 1024 microphones, which are all connected to each other. This is called an acoustic camera array. This array captures a measurement using a wide frequency range to find the sources of sound and sound pressure levels for the perceived loudness.

Software processes the sounds received from the measurement and creates an acoustic image using a camera as a visual aid. The software combines all these microphones and visualizes it on the screen of the acoustic camera.

Example of using an acoustic camera

Acoustic camera used within a building showing an example on what a person sees when using the camera
Here you see a loud sound source highlighted in the red circle.

Imagine you hear a sound but don’t know where it comes from. An acoustic camera can be used to find the source. Like thermal imaging cameras, you’ll see circles on the screen that show you where the sound comes from. This is called a sound source.

You would want to find a sound source for many different reasons. For example, when you are a product developer and want to find an unwanted noise in your product. With the acoustic camera, you can find out why your product is making this noise and change the design of your product.

Furthermore, there are many other applications, such as finding annoying sounds within buildings, finding sound leaks in walls, and monitoring noise pollution within cities. We will tell you more about that further on in this blog.

Change over time

Until some years ago, acoustic or sound cameras were only available for large companies as the measurement tools were very expensive. Using digital microphones instead of analog ones, combined with advanced AI software, the costs of producing are much lower these days. Therefore, acoustic cameras can be offered for a much lower price, still deliver the same quality, and thus become available for all company sizes.

What can you use acoustic cameras for?

As there are so many applications for an acoustic camera, we will focus on the most common applications and tell you what kind of acoustic camera fits best. These are

  • Sound localization, finding the noise sources
  • Sound monitoring, continuous environmental noise measurement
  • Fan engagement, for fun sound games for example in a stadium
  • Sound behavior, to see how the sound waves move

Sound Localization

Sound localization or noise localization is finding the unwanted sound sources. For instance, loud, annoying, or non-regulation-compliant sounds. This could be a source within a building (e.g., gaps in doors or open office space), outside (e.g., Loud vehicles or HVAC units), or to validate noise-reducing products.

To localize the sound, acoustic cameras use an array of microphones. In our case, at least 64 microphones. All these microphones capture sound and use this information for beamforming. Beamforming helps you with visual identification and finding the source of the disturbing noise.

This noise can be in a low or high frequency. Low-frequency sounds have longer sound waves, requiring a bigger surface to measure the noise. You’ll need a large acoustic camera with a big microphone array, like the CAM1K. A smaller microphone array will do a good job within the higher frequency range. For those measurements, you can use either the CAM iV64Ex or CAM64 gebruikte.

Another difference is what and where you want to perform measurements with the acoustic camera. For example the acoustic cameras CAM1K en CAM64 gebruikte, mentioned above, always need to be connected to a laptop. That way you can do complicated measurements within our cloud software Sorama Portal. However, if you are looking for a more flexible and easy-to-use device, the Sorama CAM iV64 is a good match.

The CAM iV64 is the most used acoustic camera for building and construction applications. It can be used to detect sound leaks in walls or the façade. That way a builder can reduce the amount of sound leaking from one room to another room or from inside to outside.

Sound Monitoring

Basically sound monitoring is the same as sound localization. It is mainly used in cities and other busy areas. The difference is that sound monitoring is a continuous process instead of a snapshot of that specific moment. Think of a city where some moments are busier than other moments. For example, if you would do measurements in a city on Monday 2pm, it will give you a much different outcome than Saturday 1am. To get good insights you want to monitor the sound continuously. Therefore, an acoustic camera used for Sound Monitoring, is often called an acoustic monitor.

Environmental Noise Monitoring is an example of a continuous process. With the acoustic monitor municipalities get insights where, when and how noise is created in their cities. These insights can be used to battle and solve noise pollution to create a healthier living environment. The L642 is a good example of an acoustic monitor that is often to monitor environmental noise.

Other applications for acoustic monitors

There are other applications for acoustic monitors within cities. The first one is Safety & Security. The acoustic monitor can recognize specific sounds, such as car alarms, breaking glass and aggression. When such a sound is detected, a notification can be shared with the Safety & Security center, so they can take action.

The second application is Traffic Noise Monitoring and Mobility. Especially in urban environments and highways, there is a considerable amount of noise pollution caused by traffic. With an acoustic monitor, municipalities can map the noise and with these insights they can take action to make their city quieter. Furthermore, the acoustic monitor can operate as a noise camera for loud vehicles. Combined with a video camera, it can detect vehicles, which exceed the standards.

Fan Engagement in Smart Stadiums

Besides the applications within cities, there is also a more fun application: fan engagement in Smart Stadiums. The acoustic monitor enable stadiums to interact with the fans within the stadium. For example, they can show how loud a section is and have the fans compete with each other. Or they can connect the lighting to the acoustic monitors and put the loudest fans into the spotlights, literally.

Sound Behavior

This one might sound a bit odd at first. When you place an acoustic camera, fit for Sound Behavior, in front of, let’s say a product, you can actually see how the sound behaves. The acoustic camera shows how the sound waves moves over the product. It is used by Research & Development and OEM (original equipment manufacturer) departments who want to optimize the so called ‘sound design’ of their product. Examples of the acoustic cameras, used to measure sound behavior are the CAM64 gebruikte en CAM1K, depending on the size of the product.

Conclusie

There are several different types of acoustic cameras. Most of them can be used for different applications, but finding the right fit also depends on the frequency you have to deal with, the budget you have, etc.

What we do know is that there will be more applications for the acoustic camera in the future. We notice that the more people get to know of the acoustic camera, the more requests for applications come in.

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