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

scholarly journals Controlling the Shapes of the Moiré Patterns Generated Using the Interferometry and a Spatial Light Modulator

2021 ◽  
Vol 9 (9) ◽  
pp. 960-963
Author(s):  
Joydeep Chatterjee
Keyword(s):  
Spatial Light Modulator ◽  
Michelson Interferometer ◽  
Periodic Patterns ◽  
Light Modulator ◽  
Simple Method ◽  
Grating Pattern ◽  
Straight Line ◽  
Moire Patterns ◽  
Circular Grating ◽  
Moiré Patterns

Abstract: Moiré patterns are generated by the superposition of two periodic patterns of close frequencies. This present paper proposes a simple method to bridge the conventional gap between interferometry and moiré patterns by generating moiré patterns using straight-line interference fringes from a Michelson interferometer like setup and a circular grating pattern generated on a Spatial Light Modulator (SLM). The visible variation in the geometrical shapes of the moiré patterns by varying the ratio of the periods of the two periodic patterns has also been presented. The experimental results match with the simulation results. Keywords: Moiré, Interferometry, Spatial Light Modulator, Optics, Engineering physics

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.

Velocity Measurement for Flow Particles by Using Spatial Filtering Technique Based on Sensor Array

2012 ◽  
Vol 508 ◽  
pp. 263-266 ◽  
Author(s):  
Zeng Xi Lu ◽  
Gang Yang ◽  
Zeng Shuang Wang
Keyword(s):  
Particle Velocity ◽  
Velocity Measurement ◽  
Sensor Array ◽  
Spatial Filtering ◽  
Spatial Filter ◽  
Capacitance Sensor ◽  
Filtering Method ◽  
Filtering Technique ◽  
Moving Particle ◽  
Particle Velocity Measurement

In comparison with cross correlative method based particle velocity measurement, the spatial filtering method for particle velocity measurement has the advantages of simplicity of the measurement system and convenience of data processing. In the paper a capacitive velocimeter, based on the spatial filtering method, is described. In this approach a capacitance sensor array has been used as a spatial filter for particle velocity measurements. Experiments were performed on a test rig and the experimental results show that the system relative error is within ±4% over a velocity range of 2-5m/s for a moving particle.

Optically addressed spatial light modulator: applications to spatial filtering

1993 ◽  
Author(s):  
Hongchen Zhai ◽  
Pierre H. Chavel ◽  
Francois Chataux ◽  
Shamial Mallick ◽  
Guy Premont ◽  
...  
Keyword(s):  
Spatial Light Modulator ◽  
Spatial Filtering ◽  
Light Modulator

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.

Hybrid multinary modulation using a phase modulating spatial light modulator and a low-pass spatial filter

2007 ◽  
Vol 32 (16) ◽  
pp. 2336 ◽  
Author(s):  
Zoltán Göröcs ◽  
Gábor Erdei ◽  
Tamás Sarkadi ◽  
Ferenc Ujhelyi ◽  
Judit Reményi ◽  
...  
Keyword(s):  
Spatial Light Modulator ◽  
Spatial Filter ◽  
Light Modulator ◽  
Low Pass

An Issue and its Processing in PIS Testing

2007 ◽  
Vol 364-366 ◽  
pp. 1242-1245
Author(s):  
Jin Xu ◽  
Yan Li ◽  
Zhe Bo Chen ◽  
Xu Xiang Ni ◽  
Zu Kang Lu
Keyword(s):  
Image Quality ◽  
Spatial Frequency ◽  
Spatial Light Modulator ◽  
Fourier Spectrum ◽  
Imaging System ◽  
Notch Filter ◽  
Spatial Filtering ◽  
Multiple Point ◽  
Light Modulator ◽  
Programmable Imaging

In PIS (Programmable Imaging System) testing, where the spatial frequency of the spatial light modulator is inconsistent with that of the image device, Morie Fringes are generated. To further develop the PIS instrument, it has to abate the effects of Morie Fringes on the image quality. In this paper, we implemented an approach using spatial filtering in the Fourier Spectrum. Since “ringing” phenomenon is caused by the “notch filter”, to prevent it, a multiple-point Gauss Filter based on the “notch filter” has been designed. The tests have indicated that this approach can efficiently reduce the effects of the issue on the image quality, and the images reconstructed are clear and almost free from “ringing”,thus reaching the requirements for the instrument.

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.

Sign in / Sign up

Export Citation Format

Share Document