A longitudinal magnetic field often suffers the saturation effect in a strong magnetic field region when the measurement is performed at a single-wavelength point and linear calibration is adopted. In this study, we develop a method that can judge the threshold of saturation in Stokes V/I observed by the Solar Magnetic Field Telescope (SMFT) and correct it automatically. The procedure is to first perform the second-order polynomial fit to the Stokes V/I vs. I/I_m (I_m is the maximum value of Stokes I) curve to estimate the threshold of saturation, then reconstruct Stokes V/I in a strong field region to correct for saturation. The algorithm is demonstrated to be effective by comparing with the magnetograms obtained by the Helioseismic and Magnetic Imager (HMI). The accuracy rate of detection and correction for saturation is ∼99.4% and ∼88% respectively among 175 active regions. The advantages and disadvantages of the algorithm are discussed.

当在单波长点进行测量并采用线性校准时，纵向磁场在强磁场区域往往会出现饱和效应。在这项研究中，我们开发了一种方法，可以判断太阳磁场望远镜 (SMFT) 观测到的Stokes V / I饱和阈值并自动校正它。该过程是首先对 Stokes V / I vs. I / I _m （I _m 是 Stokes I的最大值）曲线进行二阶多项式拟合以估计饱和阈值，然后重建 Stokes V /I在强场区域中校正饱和度。通过与日震和磁成像仪（HMI）获得的磁图进行比较，证明该算法是有效的。在 175 个活动区域中，饱和度检测和校正的准确率分别为 ~99.4% 和 ~88%。讨论了该算法的优缺点。