Acoustic Camera System in NVH Testing

1. What is an Acoustic Camera?

An acoustic camera is a measurement system that combines a microphone array with an optical camera, allowing the sound source to be displayed as a heat map superimposed on a real image of the object being tested. Instead of just knowing "there's noise somewhere in this area," engineers can see precisely which point on the product's surface is emitting the strongest sound, and at what frequency.

This technology is based on a signal processing technique called beamforming – combining signals from multiple microphones in an array to calculate the position and intensity of the sound source in three-dimensional space.

2. Operating Principle

An acoustic camera system consists of three main components that work in sync:

• - Microphone array: Multiple microphones arranged in a specific shape (circle, grid, star) capture audio signals from multiple directions simultaneously.
• - Optical camera: Captures real images of objects to serve as a background for the overlaid sound map.
• - Beamforming software: Calculates the time delay of sound at each microphone, thereby inferring the direction and intensity of the sound source, and then displays it as a color map (usually red - yellow - green in decreasing order of intensity).

The end result is a visual representation where engineers can "see the noise" directly on the product surface instead of just reading a generic dB number.

3. Why are Acoustic Cameras Important in NVH Testing?

Locate the noise source quickly and accurately.

Before acoustic cameras, engineers had to manually move individual microphones across different locations to locate noise sources – a time-consuming and error-prone process due to the need to repeat test conditions multiple times. Acoustic cameras shorten this process to a single measurement, displaying a complete map of noise sources in seconds.

Distinguishing multiple overlapping noise sources

In a running vehicle, there can be dozens of noise sources operating simultaneously—engine, tires, wind, HVAC system. Acoustic cameras help isolate and pinpoint each source within its own frequency range, allowing engineers to know exactly which source dominates the overall perceived noise level.

Supports faster design decision-making.

By accurately identifying the source of noise—for example, a small gap in the door seal or a resonance point on the vehicle's steel floor plate—the design team can intervene directly without the need for multiple detection tests, significantly reducing product development time and costs.

4. Some Acoustic Camera Models from Head Acoustics

4.1. HEAD VISORIC – Acoustic Camera

HEAD VISORIC is an acoustic camera system used to identify and visualize the location of sound sources in a space. The system uses multiple microphones in combination with imaging cameras to create a sound map, helping engineers quickly pinpoint the source of the noise.

Application:

• Identify the source of noise in the car.
• NVH testing
• Check the noise level of the engine and electric motor.
• Noise analysis from HVAC systems
• Check the noise levels of machinery and equipment.
• Troubleshooting in the product development process

The advantage of acoustic cameras is that instead of just seeing a frequency spectrum or SPL level, engineers can see where the sound source is located on the test object .

4.2. Head Visor M

This is a line of acoustic cameras designed for measurements requiring flexibility and rapid deployment.

The system can combine audio and visual data to assist engineers in locating noise sources. This is a suitable solution for source localization problems in labs or test areas.

Typical applications:

• - Check the car's engine and transmission.
• - Component noise analysis
• - Check the electric motor.
• - Analysis of machine noise
• - Check product quality

4.3. Head Visual MC

For tasks requiring observation of sound sources over a larger area or demanding camera configurations tailored to specific test subjects, the VISORIC MC series can be used to assist in the analysis and localization of sound sources.

A key advantage of acoustic camera systems is their ability to combine visual images and audio data , making it easier for engineers to pinpoint the area to be inspected instead of having to identify the noise source through trial and error.

5. Application of Acoustic Cameras in NVH Testing

6. Technical Factors to Consider When Choosing an Acoustic Camera

• - Number and configuration of microphones in the array: Arrays with multiple microphones offer better spatial resolution, but this needs to be balanced with cost and intended use.
• - Operating frequency range: Must match the phenomenon being measured - engine noise at low frequencies requires a different array configuration than brake screeching at high frequencies.
• - Optimal measurement distance: Each type of microphone array has a specific effective measurement distance - measuring too close or too far will affect positioning accuracy.
• - Integration with existing DAQ systems: Ensures synchronization of acoustic camera data with other vibration and sound sensors in the same test.

7. GPower Vietnam - Acoustic Camera Solutions for NVH Labs

Choosing the right acoustic camera system – from microphone array configuration to beamforming software – requires a thorough understanding of each customer's specific testing requirements. GPower Vietnam supports businesses throughout this entire process:

• - System selection consultation: Determine the acoustic camera configuration suitable for the frequency range and type of noise source to be located.
• - Supplier consultation: Connect with reputable acoustic camera brands within our international partnership network.
• - Integrated solution consulting: Ensuring the system operates seamlessly with the client's existing analytical software and DAQ system.
• - Calibration, warranty, and maintenance: Long-term technical support services ensure the acoustic camera system always operates stably and accurately.

Contact GPower Vietnam today for advice on the most suitable acoustic camera solution for your NVH lab - Hotline: 0936093289 | Email: info@gpower.com.vn