Computer-generated Moiré profilometry

Abstract

A new 3D measuring method based on computer-generated moiré fringes is proposed. The two AC components of the 0-degree and 90-degree phase-shifted fringe patterns on reference plane are prepared in advance. While the AC component of the single-shot deformed pattern is multiplied by the two prepared AC components, respectively, two computer-generated moiré fringes can be retrieved. The ratio of the two computer-generated moiré fringes is just the tangent of the phase modulated by the object. It is of great potential in real-time or even dynamical 3D measurement due to its single-shot deformed pattern feature, and it avoids the influences of the object's reflectivity simultaneously. Compared to the Fourier transform profilometry, its error is smaller due to its higher first-order spectrum. Experimental results show the feasibility and validity of the proposed method.

High precision computer-generated moiré profilometry

“…As described in the previously proposed computer-generated moiré profilometry 26 , the previous preparation must be accomplished. According to its principle, when four sinusoidal gratings with a phase difference of 90-degree in turn are projected onto the reference plane respectively, four fringe patterns captured from the reference plane can be expressed as Eqs (1–4):where R ( x, y ) presents the reflectivity coefficient of the reference plane, a donates the background component and b reflects the fringe contrast, f is the frequency of the fringe pattern, φ 0 ( x, y ) is the phase distribution modulated by the reference plane.…”

“…Recently, our group proposed a computer-generated moiré profilometry (CGMP) 26 which captures the deformed patterns rather than moiré fringes themselves to achieve phase retrieval. It effectively avoids the influence of the transient caused by moiré fringes’ direct acquisition and generally owns a higher accuracy.…”

Application of Moire Profilometry in Three-Dimensional Profile Reconstruction of Key Parts in Railway

“…It has great potential in real-time and dynamic 3D measurement because of the characteristics of its single launch deformation pattern. This method could avoid color or texture interference and has higher measurement accuracy than FTP [ 14 ]. He also proposed a high-precision computer generated MP, based on accurate elimination of background light components [ 15 ].…”

Color-encoded single-shot computer-generated Moiré profilometry

“…Although Moiré profilometry (MP) was proposed by Takasaki early in 1970 25 , its development has been severely challenged, because it is based on analyzing the Moiré fringes caused by two overlapped gratings and its optical setup is more complex than that of FTP or PMP. Recently, along with the development of computer technology, a computer-generated Moiré profilometry (CGMP) 26 was proposed. It just captures only one deformed pattern rather than directly generates and captures Moiré fringe like MP, and the Moiré fringes are generated just by the computer.…”