题 目：光学条纹图的希尔伯特黄变换分析方法

讲座人：Maciej Trusiak，波兰华沙理工大学光电子学院二年级博士生

时 间：2013.11.27（本周三）下午3：00~4:00

地 点：机械学院第三会议室

讲座内容提要：

光学条纹图分析是光学测量技术的重要组成部分，广泛应用于干涉、散斑、莫尔、结构光等光学检测技术中。作者主要研究利用经验模式分解（EMD）和希尔伯特-黄变换（HHT）的对条纹图进行分析，提出了快速二维经验模式分解算法，条纹图的计算从数分钟减少到1秒钟。讲座主要涉及一维EMD、二维EMD和HHT基本原理，以及在光学条纹图分析中的应用。

讲座人简介：

Maciej Trusiak，波兰华沙理工大学光电子学院二年级博士生，目前受我院周翔老师邀请做短期访问学者。作者在光学领域发表国际SCI论文5篇，会议论文3篇。

Title: Optical fringe pattern analysis using Hilbert-Huang transform

Basic principles of Hilbert-Huang transform (HHT) used for fringe pattern analysis are given. HHT was proposed by Norden Huang in 1998 and ever since it gained significant attention of the researchers representing different physical and engineering fields. The HHT consists in empirical mode decomposition (EMD) algorithm and subsequent Hilbert transform analysis. The EMD technique is used to adaptively decompose a signal into a finite (small) number of orthogonal oscillatory AM/FM components called intrinsic mode functions and a residue. IMFs represent signal embedded features varying on different scales.

It is described how empirical mode decomposition (EMD) algorithm aided by the Hilbert transform can be implemented as a very efficient tool for fringe pattern noise suppression, background removal and amplitude/phase demodulation. EMD is an adaptive and data-driven technique - unlike the Fourier transform it does not use any pre-assumed basis. Adaptivity of the EMD ensures significant flexibility of the EMD-based fringe pattern analysis techniques enabling efficient processing of complicated, degenerated fringe patterns obtained using various optical techniques, i.e., speckle interferometry, grating interferometry, time-averaged interferometry, fringe projection, moiré techniques etc. Several algorithmic solutions developed employing especially tailored original EMD modifications are presented. Simulations and experimental studies corroborate their efficiency, versatility and robustness.

Author: Maciej Trusiak, Warsaw University of Technology, Poland.

Maciej Trusiak received his MS degree from Warsaw University of Technology (WUT) in 2012. He is a second year PhD candidate at the Institute of Micromechanics and Photonics, WUT. His scientific interests involve adaptive fringe pattern analysis and optical metrology. He is a co-author of five journal papers (four in Optics Express and one Optics and Lasers in Engineering) and three international conference contributions. He is currently visiting prof. Xiang Zhou group in Xi'an Jiaotong University collaborating in the topic of fringe pattern processing using empirical mode decomposition approach.

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