Laser-assisted see-through technology for locating sound sources inside a structure.

Area of Science:

• Acoustics
• Optical Measurement
• Signal Processing

Background:

• Analyzing interior sound fields and locating sound sources within structures is challenging using conventional methods.
• Non-invasive techniques are highly desirable for structural acoustic analysis.

Purpose of the Study:

• To develop and validate a laser-assisted see-through technology for interior sound source localization and sound field analysis.
• To demonstrate the capability of reconstructing and observing time-varying interior sound fields.

Main Methods:

• Utilizing six lasers to simultaneously measure normal velocities on the exterior surface of a structure.
• Employing a passive sonic detection and ranging algorithm for sound source localization.
• Reconstructing the interior sound field using the Helmholtz equation least squares method.
• Applying computer tomography to observe temporal changes in the sound field.
• Developing a method using two lasers for time-invariant signals to establish transfer functions for sequential velocity measurements.

Main Results:

• Successfully located sound sources inside a solid structure.
• Reconstructed and analyzed the interior sound field.
• Observed dynamic changes in the interior sound field over time.
• Validated the laser-assisted technology experimentally.
• Demonstrated application in analyzing aerodynamically-induced sound from a projector blower.

Conclusions:

• The developed laser-assisted see-through technology provides a significant advancement in sound source localization.
• This technology enables previously unattainable applications in structural acoustics and diagnostics.
• The method offers a non-invasive approach to analyzing complex interior acoustic environments.