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Moiré pattern

About: Moiré pattern is a research topic. Over the lifetime, 1917 publications have been published within this topic receiving 27176 citations. The topic is also known as: moiré fringes & moire pattern.


Papers
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Proceedings ArticleDOI
06 Jul 2015
TL;DR: An artificial neural network approach was proposed to detect and locate moiré fringe centers of circular gratings without image preprocessing and curve fitting and showed that the neuralnetwork approach is applicable in moirés fringe centers determination and its feasibility in automating moirÉ pattern analysis with further improvement.
Abstract: Moire methods are commonly used in various engineering metrological practices such as deformation measurements and surface topography. In the past, most of the applications required human intervention in fringe pattern analysis and image processing development to analyze the moire patterns. In a recent application of using circular gratings moire pattern, researchers developed graphical analysis method to determine the in-plane (2-D) displacement change between the two circular gratings by analyzing the moire pattern change. In this work, an artificial neural network approach was proposed to detect and locate moire fringe centers of circular gratings without image preprocessing and curve fitting. The intensity values in columns of the transformed circular moire pattern were extracted as the input to the neural network. Moire fringe centers extracted using graphical analysis method were used as the target for the neural network training. The neural network produced reasonably accurate output with an average mean error of an average mean error of less than 1 unit pixel with standard deviation of less than 4 unit pixels in determining the location of the moire fringe centers. The result showed that the neural network approach is applicable in moire fringe centers determination and its feasibility in automating moire pattern analysis with further improvement.

1 citations

Book ChapterDOI
01 Jan 1993
Abstract: The operation of mask alignment is one of the most important steps in the process of fabrication of integrated circuits. In this paper we report a computer controlled mask alignment system using modified moire’ technique. In this technique the alignment is controlled in high slope region of the moire’ signal by using a single pair of grating alignment marks. Two methods have been proposed to obtain alignment. The error signal for alignment is taken as the difference of moire’ signal and a secondary signal computed from the moire’ signal. In one method this secondary signal is the inverted moire’ signal while in other it is the average value calculated from the maximal and minimal value of moire’ signal. Experiments were conducted using He-Ne laser of 0.633 μm wavelength and 25μm grating pitch. The alignment accuracy of 0.06μm has been achieved.

1 citations

Patent
16 Aug 2018
TL;DR: In this article, a set of halftone screens each comprising tiles spanning a plurality of cells, wherein at least one screen is a non-orthogonal screen and the cells comprise parallelograms being defined by a first vector having a first length and second vector having another length, were determined for each of the screens using a projection of the first and of the second vector into each axis of a print apparatus reference frame.
Abstract: In an example, a method includes determining, using a processor, a set of halftone screens each comprising tiles spanning a plurality of cells, wherein at least one screen is a non-orthogonal screen and the cells comprise parallelograms being defined by a first vector having a first length and second vector having a second length. A first and a second fundamental frequency may be determined for each of the screens using a projection of the first and of the second vector into each axis of a print apparatus reference frame, the first length and the second length. Using the first and second fundamental frequencies, it may be determined which screens are associated with moire effects below a threshold.

1 citations

Proceedings ArticleDOI
25 Nov 2008
TL;DR: In this paper, a four-step phase-shifting technique is achieved by shifting the computer-generated reference radial and circular gratings precisely to obtain in-plane displacement and strain information denoted in polar coordinate system directly.
Abstract: Circular and radial gratings are used in digital moire method in order to obtain in-plane displacement and strain information denoted in polar coordinate system directly. Four-step phase-shifting technique is achieved by shifting the computer-generated reference radial and circular gratings precisely. Basic procedures of this novel digital moire method with circular and radial gratings are explained in detail by an experimental application for large deformation analysis on a double-cracked rubber disk. By using deformed gratings, radial and circular displacements distributions are measured and distributing information of strains can also be calculated. Results of the application show that the present digital moire technique of circular and radial gratings is a valid and efficient way in measurement of both displacement and deformation for large deformation materials.

1 citations

Patent
12 Apr 2002
TL;DR: In this paper, the halftone mask is manufactured in such a way that random numbers are generated and stored in a memory correspondingly to pixels constituting mask blocks and spatial filtering is performed on the pass band corresponding to a set prescribed dot density and prescribed screen ruling.
Abstract: PROBLEM TO BE SOLVED: To provide a method of manufacturing a halftone mask which does not cause any moire, hexagonal pattern (Rosetta pattern), etc, and can make good ink transfer and with which halftone images having invariable density characteristic can be obtained, and to provide halftone images and printed matters using the mask SOLUTION: The halftone mask is manufactured in such a way that random numbers are generated and stored in a memory correspondingly to pixels constituting mask blocks and spatial filtering is performed on the pass band corresponding to a set prescribed dot density and prescribed screen ruling Then the pixel values of the mask blocks are replaced with the thresholds of the gradation ranges of bit numbers expressing the pixel values of an original image based on the cumulative distribution of the mask blocks obtained by digitization in absolute values The halftone images and printed matters are obtained by using the mask

1 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023181
2022321
202126
202048
201946
201844