标题：Modified Fourier transform profilometry based on digital time-multiplexing technique
作者：Zhou, Canlin; Li, XiaoLei; Si, Shuchun; Lei, Zhenkun; Li, YanJie
作者机构：[Zhou, Canlin; Si, Shuchun] Shandong Univ, Sch Phys, Jinan 250100, Shandong, Peoples R China.; [Li, XiaoLei] Hebei Univ Technol, Sch Mech Engn, Tian 更多
会议名称：6th International Conference on Optical and Photonic Engineering (icOPEN)
会议日期：MAY 08-11, 2018
来源：SIXTH INTERNATIONAL CONFERENCE ON OPTICAL AND PHOTONIC ENGINEERING (ICOPEN 2018)
关键词：Phase-shifting algorithm; Fourier transform; phase measuring; profilometry(PMP); filtering
摘要：In order to avoid frequency aliasing, improve the spatial resolution of the phase map in Fourier transform Profilometry(FTP), an approach based on the digital time-multiplexing technique is proposed to remove the background component from the deformed fringe pattern. Firstly, a sinusoidal fringe pattern is projected onto the tested object by digital-light-processing(DLP) projector, the fringe pattern modulated by the object's surface is captured by a CCD camera. Secondly, apply Fourier transform to the captured fringe pattern to obtain the spectrum. Thirdly, rotate the specimen's fringe pattern 90-deg to obtain the rotated fringe pattern, then obtain the new spectrum corresponding to the rotated fringe pattern. Fourthly, the new spectrum is subtracted from the original spectrum, clip the negative going values in the resultant spectrum by digital manipulation. Fifthly, filter out the first-order spectrum from the resultant spectrum by the band filter, apply inverse Fourier transform to the selected spectrum to obtain complex fields, then retrieve the phase, unwrap the wrapped phase map by the phase unwrapping algorithm. Finally, the simulation and experimental evaluations are conducted to prove the validity and performance of the proposed method. The results are analyzed and compared with those of the conventional method. The effectiveness and superiority of the proposed method have been demonstrated and verified.