Adaptive near-field beamforming techniques for sound source imaging

Area of Science:

• Acoustics
• Signal Processing
• Array Signal Processing

Background:

• Phased array beamforming is crucial for detecting and localizing far-field sound sources.
• Spatial processing faces challenges in minimizing off-axis interference and main lobe width.
• Adaptive procedures are developed to reduce side lobe contributions in spatial processors.

Purpose of the Study:

• To modify adaptive beamforming techniques for near-field source visualization.
• To estimate beamforming pressure and intensity using near-field measurements.
• To compare adaptive techniques with fixed near-field focusing for sound source resolution.

Main Methods:

• Modified minimum variance distortionless response (MVDR) and maximum side lobe (MSL) beamforming were employed.
• Near-field pressure measurements were used for estimating beamforming pressure and intensity.
• Numerical simulations in anechoic and reverberant environments with noise were conducted.
• Experimental validation was performed using near-field sound pressure measurements of a loudspeaker.

Main Results:

• Adaptive techniques demonstrated improved sound source resolution compared to fixed focusing.
• The study compared the accuracy of different weighting strategies in near-field imaging.
• Performance was evaluated in both simulated and real-world acoustic environments.

Conclusions:

• Modified adaptive beamforming techniques are effective for near-field sound source visualization.
• These methods offer enhanced accuracy in estimating acoustic pressure and intensity.
• The findings contribute to advancements in acoustic imaging and source localization.