统计最优平面近场声全息原理与声场分离技术

测量孔径尺寸的有限性，在基于空间傅里叶变换的平面近场声全息中会带来窗效应和卷绕误差. 为了克服窗效应和卷绕误差，引入了统计最优平面近场声全息技术. 运用声场叠加原理，证明了统计最优平面近场声全息的理论公式.通过在空间波数域限定kx,ky的取值范围，并离散其确定的空间波数面的途径，提出了一种确定波数矢量的方法.为了克服常规统计最优平面近场声全息技术的应用局限性——全息面一侧的声场必须为自由声场，提出了适用于统计最优平面近场声全息的、基于双全息面测量的空间声场分离技术. 通过实验和数值仿真对理论推导的正确性进行了验证. 关键词： 统计最优 平面近场声全息 波数矢量 声场分离

The principle of statistically optimal planar near-field acoustical holography and the sound field separation technique

Since the sound pressures are measured on the holographic plane with a finite size, there are windowing effects and wraparound errors in the planar near_field acoustical holography (NAH) based on spatial fast Fouries transform (FFT)_based planar NAH). In order to overcome the windowing effects and wraparound errors, statistically optimal planar near_field acoustical holography (SOPNAH) is used. The sound field superposition theory is used to prove the formulas for the SOPNAH. A simple and effective method for choosing the wave number vector is proposed by means of limiting the spatial wavenumber in the k x,k y directions and discretizing the wavenumber space plane demarcated by the maximum and minimum of k x,k y . To overcome the limitation, that sound field on one side of the holographic plane must be free, in the application of the normal SOPNAH, the sound field separation technique with double holographic planes is proposed. Some results of experiment and numerical simulation are presented to demonstrate the validity of the formulas.