为了改进传统多尺度变换滤波在电子散斑干涉(ESPI)条纹图中去噪效果和边缘细节保护不理想问题, 提出改进非下采样轮廓波(NSCT)滤波算法。采用离散平稳小波变换和NSCT变换模型, 联合非线性扩散和改进的快速非局部均值滤波算法, 进行了理论分析和实验验证, 取得了将本文中算法应用于模拟和实验ESPI条纹图滤波效果定量分析的数据。结果表明, 本文中的算法在模拟ESPI条纹图和实验图相比其它算法散斑指数最小分别为0.41121, 0.38043, 0.35362, 对应峰值信噪比最大; 该算法在提升去噪能力的同时, 能够更好地恢复条纹细节信息。研究结果为以后应用多尺度变换滤波在ESPI条纹图打下了基础。

In order to improve the denoising effect and the edge detail protection of traditional multi-scale transform filtering in the fringe pattern of electronic speckle pattern interferometry (ESPI), an improved nonsubsampling contourlet transform(NSCT) filtering algorithm was proposed. Discrete stationary wavelet transform and NSCT model were adopted with nonlinear diffusion and improved fast non local mean filtering algorithm. The algorithm was applied to the quantitative analysis of simulated and experimental ESPI fringe pattern filtering results. After theoretical analysis and experimental verification, the results show that, the minimum speckle index of the algorithm in this paper is 0.41121, 0.38043 and 0.35362 respectively in simulated and experimental ESPI fringe pattern. The peak signal-to-noise ratio is the largest. This algorithm improves the ability of denoising and recovers the details of stripes.The results lay the foundation for the application of multi-scale transform filtering in ESPI fringe pattern.