Orofino D P, Pedersen P C
Dept. of Electr. and Comput. Eng., Worcester Polytech. Inst., MA.
IEEE Trans Ultrason Ferroelectr Freq Control. 1993;40(3):238-49. doi: 10.1109/58.216837.
The angular spectrum decomposition is evaluated in terms of plane wave angular range, angular resolution, and spatial aliasing error using two-dimensional FFT (2-D FFT). The algorithm makes possible the source plane decomposition of normal velocity and pressure fields radiated by transducers of arbitrary shape, with significantly faster results achievable for planar sources. Although the angular spectrum is equally applicable to fields far from the transducer, the efficient calculation is derived specifically for fields in or very close to the source plane. An antialiasing algorithm is proposed that allows the source to be discretized with fewer sample points for a given accuracy than required with simple discretization techniques. Guidelines for the selection of sampling interval, discretization size, etc. are developed on an application-specific basis and indicate the best ratio of numerical accuracy to computational cost.
利用二维快速傅里叶变换（2-D FFT），从平面波角范围、角分辨率和空间混叠误差方面评估角谱分解。该算法能够对任意形状换能器辐射的法向速度场和压力场进行源平面分解，对于平面源可实现显著更快的结果。尽管角谱同样适用于远离换能器的场，但高效计算是专门针对源平面内或非常靠近源平面的场推导出来的。提出了一种抗混叠算法，对于给定精度，该算法允许用比简单离散化技术所需更少的采样点对源进行离散化。基于特定应用制定了采样间隔、离散化尺寸等的选择准则，这些准则表明了数值精度与计算成本的最佳比率。
