Differentiation of Moire´ Patterns by Optical Spatial Filtering

1975 ◽  
Vol 42 (1) ◽  
pp. 25-28 ◽  
Author(s):  
F. P. Chiang ◽  
R. P. Khetan
Keyword(s):  
Partial Derivative ◽  
Photographic Plate ◽  
Spatial Filtering ◽  
Image Plane ◽  
Diffraction Spectrum ◽  
Double Image ◽  
The Third ◽  
Moire Pattern ◽  
Moiré Pattern ◽  
Moire Patterns

By placing a moire´ pattern behind the first field lens of an optical spatial processor its diffraction spectrum will be formed at the first image plane of the system. This diffraction spectrum is filtered to give two images only along a selected direction. The third field lens collects the selected orders to form the Moire´ pattern at the second image plane. However, if a recording photographic plate is placed at a certain distance away from the second image plane, a double image occurs which is shifted along the selected direction. The resulting moire´-of-moire´ pattern depicts the partial derivative contours of the model.

A Case of Quasi-Infinite Visual Acuity and Illusory Size

Perception ◽  
10.1068/p6398 ◽  
2009 ◽  
Vol 38 (5) ◽  
pp. 781-783
Author(s):  
Wolf M Harmening
Keyword(s):  
Visual Acuity ◽  
Real Life ◽  
Apparent Size ◽  
Traffic Signs ◽  
Physical Size ◽  
Moire Pattern ◽  
Moiré Pattern ◽  
Moire Patterns ◽  
Size Discrepancy ◽  
Moiré Patterns

In certain real-life situations, moiré patterns can enhance the observer's ability to resolve fine spatial detail of solid structures, theoretically to unlimited degrees. An example of such a situation can be seen in traffic signs on the M25 motorway around London. Moreover, owing to the interferential nature of the moiré pattern, its angular physical size is independent of observer distance, and thus creates an apparent size discrepancy: the closer you get, the smaller the size of the pattern appears to be—an illusory situation resembling Michael Ende's tale of the pseudo-giant Mr Tur Tur.

Moiré patterns on electron micrographs, and their application to the study of dislocations in metals

1958 ◽  
Vol 246 (1246) ◽  
pp. 345-368 ◽  
Keyword(s):  
Electron Microscope ◽  
Electron Micrographs ◽  
Dislocation Line ◽  
Moire Pattern ◽  
Moiré Pattern ◽  
Transmission Electron ◽  
Crystal Films ◽  
Moire Patterns ◽  
The Individual ◽  
Moiré Patterns

The direct resolution of a crystal lattice has already been obtained in the electron microscope, with lattice spacings down to about 7 Å. Although a metal lattice has not so far been resolved in this way, a method has been developed to allow this to be carried out in an indirect manner, by means of moiré patterns. In this way, indirect resolution of crystal planes of even less than 1Å in spacing may be obtained, and the atomic array in metal lattices may be studied. The moiré patterns are obtained on transmission electron micrographs from pairs of overlapping single-crystal films of metals, prepared in a suitable manner. The mode of formation of these moiré patterns has been interpreted in terms of the kinematical theory of electron diffraction, and the relation between the patterns and the individual lattices has been considered. If a dislocation line passes through one of the metal crystals, it may be readily detected on the moire pattern. It is shown that both edge and screw dislocations in one of the crystals will give rise to terminating half-lines in the moiré pattern: the number of these terminating half-lines has been deduced, for the f. c. c. system, for any general dislocation line. The results are completely consistent with the observations, and several examples of dislocations are illustrated in the paper. Partial dislocations and stacking faults are also observed, and a full interpretation of these is given. The moiré patterns have also been used to record dislocation movements. The smallest periodicity which we have so far succeeded in resolving in the electron microscope is a moiré pattern of spacing 5.8 Å, obtained from overlapping nickel and gold crystals. The potentialities and limitations of the technique of moiré patterns are discussed in relation to their application to various problems in the metal physics of thin films, with particular reference to the study of lattice imperfections and their effect on mechanical properties.

scholarly journals What can be inferred from moiré patterns? A case study of trimesic acid monolayers on graphite

2017 ◽  
Vol 204 ◽  
pp. 331-348 ◽  
Author(s):  
Saskia Spitzer ◽  
Oliver Helmle ◽  
Oliver Ochs ◽  
Joshua Horsley ◽  
Natalia Martsinovich ◽  
...  
Keyword(s):  
Self Assembly ◽  
Lattice Parameter ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Trimesic Acid ◽  
Moire Pattern ◽  
Porous Networks ◽  
Moiré Pattern ◽  
Moire Patterns ◽  
Moiré Patterns

Self-assembly of benzene-1,3,5-tricarboxylic acid (trimesic acid – TMA) monolayers at the alkanoic acid–graphite interface is revisited. Even though this archetypal model system for hydrogen bonded porous networks is particularly well studied, the analysis of routinely observed superperiodic contrast modulations known as moiré patterns lags significantly behind. Fundamental questions remain unanswered such as, are moiré periodicity and orientation always the same, i.e. is exclusively only one specific moiré pattern observed? What are the geometric relationships (superstructure matrices) between moiré, TMA, and graphite lattices? What affects the moiré pattern formation? Is there any influence from solvent, concentration, or thermal treatment? These basic questions are addressed via scanning tunneling microscopy experiments at the liquid–solid interface, revealing a variety of different moiré patterns. Interestingly, TMA and graphite lattices were always found to be ∼5° rotated with respect to each other. Consequently, the observed variation in the moiré patterns is attributed to minute deviations (<2°) from this preferred orientation. Quantitative analysis of moiré periods and orientations facilitates the determination of the TMA lattice parameter with picometer precision.

Moiré Patterns of Twisted Bilayer Antimonene and their Structural and Electronic Transition

Nanoscale ◽  
2021 ◽  
Author(s):  
Qi An ◽  
Oussama Moutanabbir ◽  
H. Guo
Keyword(s):  
Electronic Transition ◽  
Van Der Waals ◽  
Two Dimensional ◽  
Atomic Lattice ◽  
Moire Pattern ◽  
Superlattice Structure ◽  
Moiré Pattern ◽  
Moire Patterns ◽  
Moiré Patterns

Interlayer twisting in two-dimensional (2D) van der Waals (vdW) heterostructures often leads to a periodic moiré pattern which is a superlattice structure on top of the original atomic lattice of...

Effect of Screen Angle on Moire in Printing

2013 ◽  
Vol 469 ◽  
pp. 326-330
Author(s):  
Yan Ling Liao ◽  
Xin Guang Lv
Keyword(s):  
Simulation Study ◽  
Moire Pattern ◽  
Moiré Pattern ◽  
Printing Quality ◽  
Angle Difference ◽  
Moire Patterns ◽  
The Difference ◽  
The Relationship ◽  
Moiré Patterns

Moire, an abnormal printing pattern formed by irregular screen tone, may adversely affect the printing quality and should be avoided during printing. Hence, it is necessary to understand the factors contributing to its formation. Being one of the most important factors, the effect of screen angle is discussed in this paper. To obtain the most suitable screen angle and confirm its rationality, Photoshop is used to simulate Moire patterns under different screen angle conditions and analyze the relationship between screen angles and formation of Moire pattern. When mixing two of Cyan, Magenta, Yellow, and Black colors randomly while keeping the others constant, the size of the Moire is not affected by screen angles but by the angle differences. When the difference is at 28° and 38°, Moire pattern is not obvious and the dots are evenly distributed. The screen angle difference and the screen angle of the key color are also analyzed from the Moire pattern obtained by varying screen angle between C, M, and K (Black) in the simulation study. The results show that it is reasonable to set screen angle for strong color at 15°, 45° and 75°.

scholarly journals Moiré pattern of interference dislocations in condensate of indirect excitons

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J. R. Leonard ◽  
Lunhui Hu ◽  
A. A. High ◽  
A. T. Hammack ◽  
Congjun Wu ◽  
...  
Keyword(s):  
Long Range ◽  
Direct Measurement ◽  
Quantum Systems ◽  
Matter Waves ◽  
Moire Pattern ◽  
Indirect Excitons ◽  
Moiré Pattern ◽  
Moiré Effect ◽  
Phase Singularities ◽  
Bose Einstein

AbstractInterference patterns provide direct measurement of coherent propagation of matter waves in quantum systems. Superfluidity in Bose–Einstein condensates of excitons can enable long-range ballistic exciton propagation and can lead to emerging long-scale interference patterns. Indirect excitons (IXs) are formed by electrons and holes in separated layers. The theory predicts that the reduced IX recombination enables IX superfluid propagation over macroscopic distances. Here, we present dislocation-like phase singularities in interference patterns produced by condensate of IXs. We analyze how exciton vortices and skyrmions should appear in the interference experiments and show that the observed interference dislocations are not associated with these phase defects. We show that the observed interference dislocations originate from the moiré effect in combined interference patterns of propagating condensate matter waves. The interference dislocations are formed by the IX matter waves ballistically propagating over macroscopic distances. The long-range ballistic IX propagation is the evidence for IX condensate superfluidity.

Moiré Pattern Formation on Porous Alumina Arrays Using Nanoimprint Lithography

2003 ◽  
Vol 15 (18) ◽  
pp. 1531-1534 ◽  
Author(s):  
J. Choi ◽  
R.B. Wehrspohn ◽  
U. Gösele
Keyword(s):  
Pattern Formation ◽  
Nanoimprint Lithography ◽  
Porous Alumina ◽  
Moire Pattern ◽  
Moiré Pattern
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