一类弱散射界面背向散射超声散斑一阶统计特性

对超声入射至分布有细小凹坑的界平面，这一类弱散射界面背向散射所形成的超声散斑的一阶统计特性进行了研究.在假设条件下，理论分析的结果表明，空间超声散斑的振幅服从Rice分布，而它们的相位概率密度函数是一个包含Gauss分布函数和Gauss概率积分函数的复合函数.当细孔密度非常大时，超声散斑的振幅就趋于Rayleigh分布.应用作者建立的由计算机控制扫描的实验系统，对这一类弱散射界面反射超声散斑的振幅分布进行了测量.实验结果表明，理论分析的结果是正确的，由此，所作的假设条件也是成立的. 关键词： 弱散射 超声散斑 统计特性

First-order statistical properties of ultrasonic speckles back-scattered from a kind of weak scattering interface

First-order statistical properties of ultrasonic speckles back-scattered from an interface with tiny pints on, which is considered as one kind of weak scatterin g interface, are studied in this paper. Based on four assumptions, theoretical a nalyses indicate that the amplitude of ultrasonic speckles in space is in the fo rm of Rice distribution, and the phase probability density function of the ultra sonic speckles is a compound function of Gauss distribution function and Gauss p robability integral function. When the density of the pits on the interface is v ery high, the amplitude of ultrasonic speckles becomes Rayleigh distributed. To verify the theoretical analysis conclusion, the amplitude probability distributi on of ultrasonic speckles is measured by using a set of experimental systems wit h step scanning controlled by a computer, which is built by the authors. The exp erimental results are in good agreement with the theoretical predicted results. So, the assumptions proposed in this paper are suitable for the theoretical anal yses.