Separation of Additive and Subtractive Moire´ Patterns

1971 ◽  
Vol 38 (1) ◽  
pp. 266-269 ◽  
Author(s):  
J. A. Clark ◽  
A. J. Durelli
Keyword(s):  
Experimental Determination ◽  
Spatial Filtering ◽  
Partial Derivatives ◽  
Moire Patterns ◽  
Filtering Technique ◽  
Indicial Equation ◽  
Moiré Patterns

Using a spatial filtering technique, moire´ patterns can be observed that correspond to different forms of the indicial equation describing the parametric properties of gratings and moire´. In particular both the additive and subtractive moire´s are obtained individually over the field. This method, combined with a previously developed method for obtaining spatial partial derivatives from deformed gratings, permits the experimental determination of the whole field of Cartesian shears and rigid rotations.

scholarly journals Directional Moiré Boosting Using Spatial Filtering

2021 ◽  
Vol 9 (9) ◽  
pp. 1430-1431
Author(s):  
Joydeep Chatterjee
Keyword(s):  
Spatial Light Modulator ◽  
Spatial Filtering ◽  
Spatial Filter ◽  
Fringe Analysis ◽  
Light Modulator ◽  
Small Frequency ◽  
Simple Method ◽  
Moire Patterns ◽  
Filtering Technique ◽  
Moiré Patterns

Abstract: Overlapping of two or more grating structures of small frequency differences gives rise to the Moiré patterns. While the overall moiré patterns are widely studied, in many cases – specially in case of a zonal fringe analysis – zone or direction based highlighting or suppression of moiré patterns are very helpful. This paper presents a simple method for directional boosting of moiré patterns, generated using Spatial Light Modulator (SLM) based interferometric setup, using the spatial filtering technique. Keywords: Moiré, Spatial Filter, Directional Boosting, Interferometry, Spatial Light Modulator, Optics

Moire´ Patterns of Partial Derivatives of Displacement Components

1966 ◽  
Vol 33 (4) ◽  
pp. 901-906 ◽  
Author(s):  
V. J. Parks ◽  
A. J. Durelli
Keyword(s):  
Nonlinear Deformation ◽  
Strain Tensor ◽  
Strain Analysis ◽  
The Other ◽  
Partial Derivatives ◽  
Moire Patterns ◽  
Derivatives Of ◽  
Moiré Patterns

The knowledge of the partial derivatives of displacement components is essential in strain analysis. Two methods of determining these partial derivatives using moire´ effects are presented in this paper. One consists of superposing two shifted copies of the same deformed grating of lines. The other consists of superposing two shifted copies of moire´ patterns of displacement components. Explanations of the phenomena, based on the parametric properties of superposed families of lines, are given. Applications to the determination of the nonlinear deformation and strain tensor are included.

Shear and rotation moiré patterns obtained by spatial filtering of diffraction patterns

1971 ◽  
Vol 6 (2) ◽  
pp. 134-142 ◽  
Author(s):  
J A Clark ◽  
A J Durelli ◽  
V J Parks
Keyword(s):  
Diffraction Pattern ◽  
Spatial Filtering ◽  
Circular Ring ◽  
Fourier Optics ◽  
Fraunhofer Diffraction ◽  
Diametral Compression ◽  
Moire Patterns ◽  
Diffraction Patterns ◽  
Indicial Equation ◽  
Moiré Patterns

Two superposed gratings can produce many other moiré patterns in addition to the pattern commonly observed. They correspond to different forms of the indicial equation employed in parametric descriptions of moiré phenomena. An analysis of the Fraunhofer diffraction pattern of two superposed gratings by the methods of Fourier optics shows that the different moiré patterns can be separately observed by spatial-filtering techniques. Examples of additive and subtractive moiré patterns obtained individually over the whole field of two superposed gratings are presented. This method is combined with a previously developed method for obtaining partial derivatives from deformed gratings as a direct moiré pattern (rather than as moiré of moiré) to determine experimentally the whole field of cartesian shears and rigid rotations. The method is applied to a circular ring subjected to diametral compression.

Moiré patterns: An accurate technique for determination of the locus of the centres of rotation

1985 ◽  
Vol 18 (7) ◽  
pp. 501-509 ◽  
Author(s):  
S.D. Gertzbein ◽  
K.H. Chan ◽  
M. Tile ◽  
J. Seligman ◽  
A. Kapasouri
Keyword(s):  
Moire Patterns ◽  
Moiré Patterns

Determination of basic grids for subtractive moire patterns

1991 ◽  
Vol 30 (10) ◽  
pp. 1258 ◽  
Author(s):  
Salvador Bara ◽  
Zbigniew Jaroszewicz ◽  
Andrzej Kolodziejczyk ◽  
Vicente Moreno
Keyword(s):  
Moire Patterns ◽  
Moiré Patterns

Moire Fringes on Precipitates in Quenched and Aged Beryllium

1968 ◽  
Vol 26 ◽  
pp. 426-427
Author(s):  
F. J. Fraikor ◽  
A. W. Brewer
Keyword(s):  
Ternary Phase ◽  
Volume Fraction ◽  
Age Hardening ◽  
Orientation Relationships ◽  
Solute Content ◽  
Moiré Fringes ◽  
Moire Patterns ◽  
Total Volume Fraction ◽  
Diffraction Patterns ◽  
Moiré Patterns

A number of investigators have examined moire patterns on precipitate particles in various age-hardening alloys. For example, Phillips has analyzed moire fringes at cobalt precipitates in copper and Von Heimendahl has reported on moire fringes in the system Al-Au. Recently, we have observed moire patterns on impurity precipitates in beryllium quenched in brine from 1000°C and aged at various temperatures in the range of 500-800°C. This heat treatment of beryllium rolled from vacuum cast ingots produces the precipitation of both an fee ternary phase, AlFeBe4, and an hcp binary phase, FeBe11. However, unlike a typical age-hardening alloy, the solute content of this material is low (less than 1000 ppm of Fe and 600 ppm of Al) and hence the total volume fraction of precipitates is small. Therefore there is some difficulty in distinguishing the precipitates and their orientation relationships with the beryllium matrix since the weak precipitate spots generally do not appear on the diffraction patterns.

Experimental determination of a state equation for dissipative granular gases

1999 ◽  
Vol 96 (6) ◽  
pp. 1111-1116 ◽  
Author(s):  
E. Falcon ◽  
S. Fauve ◽  
C. Laroche
Keyword(s):  
Experimental Determination ◽  
State Equation ◽  
Granular Gases
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