声全息技术空间分辨率高、计算速度快，能够对在结构内部传播的结构波进行可视化。该技术的出现为超衍射极限分辨率的检测提供了重要方向。本文主要研究近场超声在薄工件中的传播以及声场与微小缺陷相互作用的规律，基于近场声全息建立纵波信号与工件结构、缺陷类型的定量关系，找到可以通过工件表面声场特性来判别近场区域内是否存在缺陷的方法，将计算结果与有限元仿真进行对比，以验证该方法的正确性。该模型对于提高近场检测分辨率以及微小缺陷的特征提取具有一定的指导意义。

The acoustic holography technique has high spatial resolution and fast calculation speed, and it can visualize structural waves propagating inside a structure.This technique provides a significant direction for the super-diffraction limit resolution detection.Here, the propagation of near field ultrasonic wave in thin workpieces and the law of interaction between acoustic field and micro defect were studied.The quantitative relations among longitudinal wave signal, workpiece structure and defect types were established based on the near field acoustic holography (NAH).A method to judge if there are defects in near field area was found with the acoustic field characteristics of workpiece surface.Finally, the calculation results were compared with those of the finite element simulation to verify the correctness of the method.It was shown that the method provides a certain guide for improving the near field detection resolution and the feature extraction of micro defects.