Pockels效应表面电荷测量技术以其特有的技术优势逐步用于表面放电和等离子体的研究,然而如何准确获取表面电荷分布仍然是一个重要的研究课题。对Pockels效应表面电荷测量技术中的表面电荷反演算法进行研究,采用二维傅里叶变换将测量信号和表面电荷的复杂关系转换到频域中进行计算,并采用维纳滤波算法进行信号处理。计算结果和传统算法的计算结果进行了对比,结果表明,改进算法在数值计算过程中考虑材料厚度、介电特性及不同位置电荷影响等因素,计算方法更为合理。该方法可用于不同材料表面电荷的测量计算。另外,算法中维纳滤波器是计算算法中关键的组成部分,对降低系统噪声,提高数值计算的稳定性能够起到很重要的作用。
The surface charge measurement method based on Pockels effect has been used to investigate the surface discharge and plasma phenomena due to its remarkable advantage. However, it remains an important subject to obtain the accurate results of surface charge distribution. In this paper the inversion algorithm research on charge density calculation in surface charge measurement based on Pockels effect was carried out. Two-dimensional Fourier transform and Wiener filter techniques were employed in the algorithm and the relationship between potential measured by Pockels crystal and surface charge density was processed in spatial frequency domain. This improved method considers the influence of sample’s thickness and permittivity, and it also considers the impact of charges at different positions. Therefore, it is a better solution in calculating the charge density on different samples with different thickness. Besides, Wiener filter plays an important role in this algorithm, which reduces the system noise and improves the stability of numerical calculation.