Optimized two-dimensional imaging of transient sound fields using a hybrid transient acoustic holography

Abstract

A hybrid transient acoustic holography (HTAH) is presented to visualize the two-dimensional transient sound fields radiated from planar sources with unknown locations and dimensions, by combining the time reversal source localization with the near-field acoustic holography (NAH) based on the interpolated time domain equivalent source method (TDESM). Based on the near-field measurements with a microphone array, the time reversal source focusing algorithm is used to find out the hotspots of the sound sources on the equivalent source plane, which suggests the collocation of equivalent sources. The interpolated TDESM based NAH is then employed to reconstruct and image the transient sound field on the reconstruction plane. The proposed HTAH technique can reduce the elements number of microphone array by only collocating the equivalent sources in the vicinity of the “real” sound sources. The visualization of the transient sound fields radiated from single-planar-piston and dual-planar-piston model is studied by numerical simulations, respectively. The experiments are performed in a semi-anechoic chamber by using two baffled loudspeakers. Both the simulation and experimental results revealed that this hybrid scheme can realize a better two-dimensional imaging of transient sound fields than the original interpolated TDESM based NAH in the measurement using same amount of microphones.