一种用于提高点源法MTF检测精度的去噪方法

Denoising Method for Improving Detection Accuracy of Point Source Method by MTF

使用点源法可以严密检测调制传递函数(MTF),能够有效检验各个方向的MTF值,可用于空间探测相机在轨性能的监测。但点源图像存在噪声,利用传统滤波方法对其进行去噪处理,会存在检测精度不足甚至出现MTF曲线阶跃近似为0的现象,从而影响其对成像质量的评判。因此,根据点源图像光强分布的特点,提出一种基于平缓区均值的点源图去噪方法,并将该方法与传统滤波方法进行定量比较。仿真和实验结果表明:该方法将MTF曲线的检测率提高到90.91%以上,相比于传统滤波方法中效果最好的中值滤波,MTF的检测精度能提高98.73%,同时提高图像的峰值信噪比和结构相似度。

Point source method can rigorously detect the modulation transfer function(MTF).The method can effectively test the MTF value in all directions and can be used to monitor the on-orbit performance of space detection cameras.However,there is noise in the point source image,and the traditional filtering method is used to denoise it.The detection accuracy may be insufficient,and even the phenomenon that the MTF curve step is approximately 0,which affects the evaluation of image quality.Therefore,depending on the characteristics of the light intensity distribution of the point source image,a point source image-denoising method based on the mean value of the flat area is proposed.This method is quantitatively compared with the traditional filtering method.Simulation and experimental results show that this method increases the detection rate of the MTF curve to more than 90.91%.Compared with the best median filtering in traditional filtering methods,the detection accuracy of MTF can be improved by 98.73%,improving the peak signal-to-noise ratio and structural similarity of images.