Xu Wenjun, Tang Chen, Gu Fan, Cheng Jiajia
Appl Opt. 2017 Apr 1;56(10):2843-2850. doi: 10.1364/AO.56.002843.
It is a key step to remove the massive speckle noise in electronic speckle pattern interferometry (ESPI) fringe patterns. In the spatial-domain filtering methods, oriented partial differential equations have been demonstrated to be a powerful tool. In the transform-domain filtering methods, the shearlet transform is a state-of-the-art method. In this paper, we propose a filtering method for ESPI fringe patterns denoising, which is a combination of second-order oriented partial differential equation (SOOPDE) and the shearlet transform, named SOOPDE-Shearlet. Here, the shearlet transform is introduced into the ESPI fringe patterns denoising for the first time. This combination takes advantage of the fact that the spatial-domain filtering method SOOPDE and the transform-domain filtering method shearlet transform benefit from each other. We test the proposed SOOPDE-Shearlet on five experimentally obtained ESPI fringe patterns with poor quality and compare our method with SOOPDE, shearlet transform, windowed Fourier filtering (WFF), and coherence-enhancing diffusion (CEDPDE). Among them, WFF and CEDPDE are the state-of-the-art methods for ESPI fringe patterns denoising in transform domain and spatial domain, respectively. The experimental results have demonstrated the good performance of the proposed SOOPDE-Shearlet.
去除电子散斑干涉（ESPI）条纹图中的大量散斑噪声是关键步骤。在空间域滤波方法中，定向偏微分方程已被证明是一种强大的工具。在变换域滤波方法中，剪切波变换是一种先进的方法。在本文中，我们提出了一种用于ESPI条纹图去噪的滤波方法，它是二阶定向偏微分方程（SOOPDE）和剪切波变换的结合，称为SOOPDE - 剪切波变换。在此，剪切波变换首次被引入到ESPI条纹图去噪中。这种结合利用了空间域滤波方法SOOPDE和变换域滤波方法剪切波变换相互受益这一事实。我们在五个质量较差的实验获得的ESPI条纹图上测试了所提出的SOOPDE - 剪切波变换，并将我们的方法与SOOPDE、剪切波变换、加窗傅里叶滤波（WFF）和相干增强扩散（CEDPDE）进行比较。其中，WFF和CEDPDE分别是变换域和空间域中用于ESPI条纹图去噪的先进方法。实验结果证明了所提出的SOOPDE - 剪切波变换的良好性能。
