磁粉探伤系统工件表面微裂纹散焦图像复原

讨论荧光磁粉探伤系统散焦图像复原处理问题．介绍磁粉探伤系统的组成，描述散焦现象光学原理及其数学表达；对观测图像采用方差估计方法计算信噪比，采用参数辨识方法获得散焦半径并计算点扩散函数，运用Wiener滤波器进行图像复原并用散焦半径评判图像复原效果．通过对模拟和真实图像数据的仿真，表明该复原方法能够实现散焦磁痕图像复原，符合磁粉探伤系统的对裂纹识别要求．

Restoration of Out-of-focus Crack Images on Part Surface in Magnetic Particle Testing System

In this paper, out-of-focus image restoration processing of the magnetic particle testing system is discussed. We introduce the construction of the magnetic particle testing system and the optical principle of out-of-focus phenomena,describing the mathematical expression of an out-of-focus process. The mean square estimate algorithm is used to obtain the signal-to-noise ratio of the observed image. A method based on the parameter identification is used to compute the point spread function. Restoration processing on the out-of-focus image is implemented using the Wiener filter. The out-of-focus radius is proposed to evaluate quality of the restored image. Simulation results on synthetic and real images demonstrate that the restoration method satisfies the requirement of crack identification for magnetic particle testing system.