Diffraction effects in moiré deflectometry

Grating pseudo-imaging with polychromatic and finite extension sources

“…With this setting, the high contrast pseudo-image (1, 1) is now real, with a slope 1/2. The pseudo-images (1, m), (2,5) and (3,8), indexed in the Fig. 7, are now "compressed" with small slopes under the pseudo-image (1, 2).…”

“…There are a number of phenomena in which this general property is revealed: self-imaging or Talbot effect, joint Talbot effect, Lau effect, incoherent grating-lens imaging, misfocused diffraction convolution and generalized Lau effect or pseudo-imaging [1][2][3][4][5][6][7][8][9]. Many applications are based on these effects: e.g., moiré deflectometry and metrology, Talbot interferometry and a number of spectroscopic techniques based on Talbot and Lau effects are known and widely used [10][11][12][13][14][15][16][17][18].…”

“…Talbot and Lau effects have been investigated under polychromatic sources [3,16], but to our knowledge, there are no similar studies for pseudo-imaging. In this work a generalization of the formula derived in references [25] to [27], which include polychromatic sources, is presented.…”

Lissajous figure-based single-frame collimation technique

“…In this technique the light beam passes through a diffraction grating of period p and a mask located at a Talbot plane of the grating, situated at z T = 2p 2 / , [3,8,16]. The mask is composed by two diffraction gratings with the same period p and displaced laterally a distance p/4.…”

A Comparison of Electronic Heterodyne Moire Deflectometry and Electronic Heterodyne Holographic Interferometry for Flow Measurements

“…An approximate expression fur the intensity pattern of these fringes can be calculated from first principles (30,31). That expression is given by (5)), and x/p and ye/p are phase shifts related to the relative translation and rotation of the Ronchi gratings.…”