Interferometric fringes projection system for 3D profilometry and relief investigation

Abstract

We present a new 3D full-frame profilometer based on structured laser light projection method. This device takes advantage of the polarization states splitting technique for producing and shifting multiple sinusoidal Young's interference patterns that are projected on the inspected surface. The principle of the technique is presented and we discuss the advantages of monochromatic light projection method as a mean to overcome ambient lighting for in-situ measurement. Some results that we obtained on objects from the Egyptian Department of the British Museum are presented to demonstrate that 3D laser profilometry is a worthwhile technique for epigraphic investigations where naked-eye inspections fail.

Digital holographic camera with extended stochastic illumination for non-destructive inspection of silicon optics

“…In the proposed scheme shown in figure 4, the scattering medium is created using a combination of two ground glass diffusers. Thus, the diverting beam created using equation (10) propagates through these two diffusers, which adds random phase to the illumination beam. The illumination beam shown in figure 5(a) propagates to the first diffuser D 1 according to the Fresnel diffraction equation ( 6) and is represented as…”

A novel spatial phase-unwrapping method based on single-pixel binarized line pattern for real-time 3D measurement

“…However, the jitter between the adjacent pattern is inevitable, so some spike-like errors may appear in the unwrapped phase shown in figure 14(b). These errors can be eliminated by a proper median filter [8], and the corrected unwrapped phase is shown in figure 14(c). For a single reconstruction, the total time from reading pattern to displaying the reconstructed result is approximately 32 ms, so the display rate can be set to 25 fps.…”

“…Due to the advantages of non-contact, high speed, and high precision, optical measuring techniques based on structured light [1][2][3][4][5] and interferometry [6][7][8] have developed rapidly and been widely used in various fields in the past few decades. Fringe projection profilometry is one of structured light techniques and can be divided into two categories: Fourier transform profilometry (FTP) and phase-shifting profilometry * Author to whom any correspondence should be addressed.…”

Analysis of Roman pottery graffiti by high resolution capture and 3D laser profilometry

“…In particular, laser profilometry has been proposed as a tool for measuring roughness parameters of the topography of surfaces (Stemp and Stemp, 2001), and to quantitatively discriminate worn stone tools according to their use on different contact materials (Stemps et al, 2009(Stemps et al, , 2010Evans and Donahue, 2008). 3D laser profilometry has also been used to help determine the tools used to engrave writings (Carcagnì et al, 2005) and for epigraphic purposes (Moreau et al, 2005). In our paper we show the efficiency of 3D laser profilometry as well as high resolution photography as powerful means to decipher illegible engraved inscriptions.…”