窗函数对光学空间滤波效果的影响分析

Effect of Window Function on the Spatial Filtering

为改善光学空间滤波的效果,分析说明了低通滤波器窗函数对光学空间滤波效果的影响。提出了相同通频区域下选择窗函数的两个要求即更窄的频谱主瓣宽度和更小的旁瓣高度,并运用MATLAB模拟了基于4f系统的光学空间滤波。结果表明,窗函数频谱主瓣宽度直接影响滤波结果的轮廓可见度,频谱旁瓣直接影响着频域截断带来的吉布斯波纹的大小。为如何选择滤波器透过率分布提供了理论参考。

To improve the effect of the optical spatial filtering, the effect of the window function on lowpass spatial filtering is analyzed. And the requirements are brought forward to window functions which are narrower main lobe and weaker intensity of the side lobe of the spectrum. Subsequently the spatial filtering with the window function is simulated by MATLAB. The simulation results prove that the width of the main lobe of the window function influenles the visibility of the frame directly, and the side lobe of the spectrum of the window function influences the size of Gibbs wave induced by the spectrum cutoff directly. A reference is offered to the design of the window function of the lowpass spatial filter.