Research on projection grating pitch in GTAW surface sensing based on Fourier transform profilometry

Xian Hu; Nansheng Liu; Xiaopu Ai; Yiqing Wei; Xiaorui Liu; Sheng Wei

doi:10.1117/12.838399

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30 November 2009 Research on projection grating pitch in GTAW surface sensing based on Fourier transform profilometry

Xian Hu, Nansheng Liu, Xiaopu Ai, Yiqing Wei, Xiaorui Liu, Sheng Wei

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Proceedings Volume 7506, 2009 International Conference on Optical Instruments and Technology: Optical Systems and Modern Optoelectronic Instruments; 750629 (2009) https://doi.org/10.1117/12.838399
Event: International Conference on Optical Instrumentation and Technology, 2009, Shanghai, China

Abstract

Selecting an appropriate pitch is one of the most important aspects to ensure the system measurement range and precision in grating projection principle of 3D profile measurement while the Fourier transform frequency spectrum is separated completely. According to the concept of the equivalent wavelength, the basic requirement for measurement system and the selection of projection grating pitch are discussed in this paper to avoid shadows and frequency spectrum alias in a crossed-optical-axes system in Fourier Transform Profilometry (FTP). The influence of CCD sampling to the FTP is also discussed to obtain CCD sampling condition. When the CCD sampling frequency is unchanged, it is necessary to reduce the grating frequency which means to increase the grating pitch to satisfy the sampling condition. Finally, the range of the grating pitch is determined, and the optimal grating pitch is obtained after the experiments.

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Xian Hu, Nansheng Liu, Xiaopu Ai, Yiqing Wei, Xiaorui Liu, and Sheng Wei "Research on projection grating pitch in GTAW surface sensing based on Fourier transform profilometry", Proc. SPIE 7506, 2009 International Conference on Optical Instruments and Technology: Optical Systems and Modern Optoelectronic Instruments, 750629 (30 November 2009); https://doi.org/10.1117/12.838399

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