电子散斑相位主值图的等值线正余弦滤波方法

电子散斑干涉测量相位主值图含有大量的噪声,在对相位主值图进行解缠处理前,一般先要对其进行去噪处理。针对相位主值图的特点,提出一种利用条纹方向信息的等值线正余弦滤波方法。首先由相位主值图求取其方向图,进而得到条纹等值线窗口,最后对相位主值图在条纹等值线窗口内进行正余弦滤波。和已有的滤波方法相比,它具有优点:相位主值图中的跳变信息保持非常好;由于是在等相位线上进行滤波,对相位信息没有损伤;更好地消除相位主值图中的散斑噪声。模拟图实验和真实图实验均验证了该方法的有效性。

Fringe-Contoured-Window Sine/Cosine Filter for Saw-Tooth Phase Maps of Electronic Speckle Pattern Interferometry

In electronic speckle pattern interferometry(ESPI),the saw-tooth phase map obtained by the phase-shifting technique is inherently full of speckle noise.Noise reduction must be carried out to suppress the high-level noise before it is unwrapped.In accordance with the feature of the saw-tooth phase maps,an adaptive filter is developed combining the classical sine/cosine filter and the fringe orientation information of the saw-tooth phase map.Fringe orientation map is firstly generated from the saw-tooth phase map,and then the fringe-contoured-window is derived accordingly.Finally,the filtering is carried out within the window.Comparing with existed filters,it has a better performance on phase jump information preservation and does not have any blurring effect on the phase distribution providing the filtering is implemented on the equal-phase window.Moreover,its capability of noise reduction is more powerful.The effectiveness and advantages of the novel filter have been verified by both simulated and real saw-tooth phase maps.