Heterodyne moiré surface profilometry

Abstract

In this study, a novel moiré fringe analysis technique is proposed for measuring the surface profile of an object. After applying a relative displacement between two gratings at a constant velocity, every pixel of CMOS camera can capture a heterodyne moiré signal. The precise phase distribution of the moiré fringes can be extracted using a one-dimensional fast Fourier transform (FFT) analysis on every pixel, simultaneously filtering the harmonic noise of the moiré fringes. Finally, the surface profile of the tested objected can be generated by substituting the phase distribution into the relevant equation. The findings demonstrate the feasibility of this measuring method, and the measurement error was approximately 4.3 μm. The proposed method exhibits the merits of the Talbot effect, projection moiré method, FFT analysis, and heterodyne interferometry.

High precision computer-generated moiré profilometry

“…There are many real-time measuring methods 13–18 based on PMP, however, their accuracy limited by various factors is still an unsolved problem. Besides, Moiré Surface Profilometry 19–23 with the merits of being stable and economical, is also a promising method in various measurements. In moiré-based surface measurements, the object surface information is recorded in the moiré fringes and the equal-depth contours can be used to determine the height distribution of the object.…”

Patient-specific 3D models created by 3D imaging system or bi-planar imaging coupled with Moiré–Fringe projections: a comparative study of accuracy and reliability on spinal curvatures and vertebral rotation data

“…New alternatives have been proposed recently [14][15][16][17]. Among these, the 'Moiré-Fringe' technique uses an optical process assessing the 3D geometry of the back by analysis of the deformation induced by the relief on successive systems of projected luminous bands [18,19]. This recently available technique (Biomod3S Ò ) (B3S) has the theoretical advantage of being used with any commercially available X-ray system capable of frontal and sagittal acquisitions.…”