博士生张航瑛参加国际会议回国报告

汇报题目：参加SPIE会议总结报告

汇报时间：2019年7月09日 (星期二)  15:00

汇报地点：西二楼东118会议室

汇报人：张航瑛

会议名称：SPIE Optical Metrology 2019

会议时间：23-27 June 2019

会议地点：Munich, Germany

会议简介：

SPIE Optical Metrology is the premier European conference for scientists, engineers, researchers, and product developers to discuss the latest research in measurement systems, modeling, video metrics, and inspection.

参加论文信息：

Title: Two-shot fringe pattern phase demodulation using the extreme value of interference with Hilbert-Huang per-filtering

Author: Hangying Zhang, Hong Zhao*, Jinlei Zhao, Zixin Zhao, and Chen Fan

Abstract: The extreme value of interference (EVI) algorithm is a very fast and efficient method for the fringe pattern phase demodulation. It requires only two arbitrarily phase-shifted frames in which the phase shift between interferograms can be determined by searching the maximum and the minimum of the normalized interference patterns, then the measured phase is obtained by an arctangent function. Compared with other two-frame demodulation algorithms, the EVI algorithm has great advantages. Firstly, the EVI algorithm is simple and the calculation speed is fast. Secondly and more importantly, it works very well even if the number of fringes of the interferogram is less than one. However, to make this method work, the fringe should be normalized in advance, which is sometimes not a satisfactory requirement. The effects of uneven background terms, modulation amplitude variations, and random noise in the fringe pattern will make the normalization of the fringes extremely complex. Therefore, by employing the Hilbert–Huang transform (HHT) based pre-filtering in this paper, the background intensities and modulation amplitudes of the two interferograms are suppressed and normalized respectively. Then, phase demodulation is implemented using the EVI method. Because of the HHT process, the demodulation result is greatly improved in plenty of situations. Both simulation and experimental studies have shown that the proposed improved method makes it easier to determine the phase distribution with high precision even under complex conditions.