抗差估计在倾斜刃边法MTF检测中的应用分析

传统倾斜刃边法没有充分考虑噪声的影响,在进行刃边直线拟合和ESF(edge spread function)拟合时均采用最小二乘拟合估计,当影像噪声较大时会使得调制传递函数MTF(modulation transfer function)重建结果失真。采用抗差估计代替最小二乘估计,优化了传统倾斜刃边法中刃边直线拟合和ESF拟合过程,并采用模拟仿真的方法对倾斜刃边法的边缘直线拟合精度及MTF重建精度进行了评估与分析。实验结果表明,基于抗差估计的倾斜刃边法可有效抑制噪声影响,边缘直线拟合结果及MTF重建结果均与真实值吻合较好,且稳定性强。

Application Analysis of Robust Estimation in MTF Determination by Slant Edge Method

The traditional slant edge method does not fully take the influence of noise into consideration by adopting the least-squares estimation in the fitting of step edge line and ESF,resulting in distorted MTF reconstruction when the image noise is significant.In this paper,robust estimation is used instead of least squares estimation to optimize the fitting process of step edge line and ESF in the traditional slant edge method.Evaluation and analysis of the accuracy of step edge line fitting and MTF reconstruction is carried out by simulation technique.The experimental results show that the slant edge method based on robust estimation can effectively suppress the influence of noise with consistent performance and that step edge line fitting and MTF reconstruction are in satisfactory agreement with the real values.