声场分离技术及其在近场声全息中的应用

提出空间声场分离技术，突破了近场声全息（NAH）的应用局限.它们的局限在于全息面一侧的声场必须是自由声场，即要求所有的声源必须位于另一侧.利用波数域内的波场外推理论及声压的标量叠加原理，建立起声场分离技术的双全息面实现方法，利用波数域内的Euler公式及粒子振速的矢量叠加原理，建立起该技术的单全息面实现方法.该技术的一个突出优点是在具有背景噪声的全息测量情况下, 可以消除背景噪声对全息变换结果的影响.理论的推导表明该技术方法的正确性，而仿真算例和实验则显示该技术的可行性和有效性. 关键词： 声全息 波数域 声场分离 背景噪声

Sound field separation technique and its applications in near-field acoustic holography

Sound field separation technique has been proposed, which overcomes the limitation on applications of near_field acoustic holography (NAH). The limitat ion is that the sound field on one side of holographic plane must be free,that is t o say, all the sound sources must be confined to the other side. Sound field sep arat ion technique with double holographic planes has been built according to the wav e field extrapolation theorem and the superposition theorem of sound pressure sc alar in wave_number domain, and the technique with single holographic planes has also been built according to Euler's formulation and the vector superposition t heorem of particle velocity in wave_number domain. A particular feature of the t echnique is that the influence of background noise on reconstructed results can be removed while retaining the background noise in the holographic measurements. The derivation of the principle verifies the technique theoretically, and the c omputer simulations and experiment demonstrate its feasibility and effectiveness .