Fourier transform profilometry (FTP) is an established non-contact method for 3D sensing in many scientific and industrial applications, such as quality control and biomedical imaging. This phase-based technique has the advantages of high resolution and noise robustness compared to intensity-based approaches. In FTP, a sinusoidal grating is projected onto the surface of an object, the shape information is encoded into a deformed fringe pattern recorded by a camera. The object shape is decoded by calculating the Fourier transform, filtering in the spatial frequency domain, and calculating the inverse Fourier transform; afterward, a conversion of the measured phase to object height is carried out. FTP has been extensively studied and extended for achieving better slope measurement, better separation of height information from noise, and robustness to discontinuities in the fringe pattern. Most of the literature on FTP disregards the software implementation aspects. In this chapter, we return to the basics of FTP and explain in detail the software implementation in LabVIEW, one of the most used data acquisition platforms in engineering. We show results on three applications for FTP in 3D metrology.
Part of the book: Digital Systems