Research on application of patch near-field acoustic holography using acoustic radiation modes with double layers

To solve the problems of near-field acoustic holography in actual applications, research based on acoustic radiation modes with double layers is studied in this paper. The sound pressure model by using acoustic radiation modes is selected to express the sound field firstly. Then, the sound field separation with double pressure measurement layers has been applied to remove the interference from the opposite direction. Thirdly, the method based on data interpolation and extrapolation is put forward to increase the holographic value equivalently, the results of which are closer to the actual measured value obtained by more measuring points. Numerical simulations based on the theoretical description are conducted to demonstrate the validity of the proposed method, and experiments for a boundary constraint steel plate and a loudspeaker are performed to demonstrate its feasibility

Sound field separation technique using the principle of double layer patch acoustic radiation modes

In order to solve the problems of near-field acoustic holography in applications such as external interference and aperture effects, a sound field separation technique using the principle of double layer patch acoustic radiation modes is proposed in this paper. The radiated acoustic pressures over two planar surfaces at certain distances from the sources are calculated first. Then, the effects resulting from the backscattering interference in non-free sound fields can be eliminated by a double-layer sound field separation technique. Next, data interpolation and extrapolation are performed on the separated data to increase the sound source's pressures on the holographic plane equivalently for holographic images with higher spatial resolution. Simulation and experimental results demonstrate that good agreements can be obtained with few measuring points

Sound field separation technique using the principle of double layer patch acoustic radiation modes

In order to solve the problems of near-field acoustic holography in applications such as external interference and aperture effects, a sound field separation technique using the principle of double layer patch acoustic radiation modes is proposed in this paper. The radiated acoustic pressures over two planar surfaces at certain distances from the sources are calculated first. Then, the effects resulting from the backscattering interference in non-free sound fields can be eliminated by a double-layer sound field separation technique. Next, data interpolation and extrapolation are performed on the separated data to increase the sound source's pressures on the holographic plane equivalently for holographic images with higher spatial resolution. Simulation and experimental results demonstrate that good agreements can be obtained with few measuring points