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.

An Analysis of the Effect of Diaphragm Shape on the Contrast of Filtered Moiré Fringes

Abstract: The paper shows that, by suitably selecting the shape, dimensions and orientation of the diaphragm through which the moire fringes formed by crossed gratings are viewed, the contrast of the fringe pattern of interest may be maximised with respect to accompanying noise. Computer simulation is used to give quantitative information regarding the improvement obtained. The results have potential application in the design of transducers for measuring displacement using moire fringes.

Using the moiré effect to increase the accuracy of diffraction methods for monitoring the geometrical parameters and the spatial position of objects

Abstract: This paper discusses a diffraction method of monitoring that makes it possible to use a measurement signal's phase component that carries data concerning the geometrical shape and spatial position of an object. To increase the measurement accuracy and sensitivity, a data-processing optical system was implemented in which the test object is illuminated by two beams of coherent radiation displaced in space. This made it possible to introduce a phase shift between their frequency spectra while varying the parameters of the object and to obtain moire interference fringes in the recording plane, by analyzing which data can be obtained concerning the test object. An example is given of the use of the method to investigate the shape of the edge profile of an object.

Moire-free color halftoning using 2x2 printer modeling

Abstract: This paper introduces a moire-free color half toning algorithm. Moire patterns might appear in traditional halftone images. This could be caused by interference among halftone screens of different colors, or beating between he input image and the screens. In our algorithm, we adjust the halftone screens of different colors, or beating between the input image and the screens. In our algorithm, we adjust the halftone output in such a way that the low-frequency difference between the input and the appearance of the output is minimized. Due to non-linear color mixing, the appearance of a color print is not a simple combination of CMYK four channels, and is hence not easily predictable. We use the 2 by 2 printer model to estimate the pixel-level CIE-Lab values from the halftone output. Next we calculate the difference between the original CIE-Lab input image and the 2 by 2 estimation and run a low-pass filtering on the result. Then, we feed back the low-frequency difference into the input. The low-frequency-feedback process cancels the potential color moire patterns.

Moiré-free color halftoning using hexagonal geometry and spot functions

Abstract: Hexagons are widely observed as a packing or tiling geometry in nature, yet they appear to have been avoided in conventional halftone tiling. A goal of the present study is to understand the potential barriers that have prevented their use and present new halftone geometry options that overcome the issues while offering several potential benefits. While conventional halftone geometries often include the fourth screen (e.g., yellow) in a suboptimal manner, the hexagonal geometry presented here can include a clustered-dot fourth screen moire-free. Hexagonal screens can appear to have smoother texture. Due to differences in packing geometry and touch point geometry, hexagons have the potential to possess different tone reproduction characteristics, which may be favorable for some marking processes. We also present a parametrically controlled hexagonal halftone spot function that allows for optimization of dot touch points and provides compact growth. The controllable touch points can prevent a tone reproduction discontinuity, while the compact growth throughout the gray range ensures maximum stability. Additionally, we present a three-colorant dot-off-dot halftone configuration using hexagonal geometry. Examples are provided.

Varifocal equilateral hyperbolic zone plates obtained by rotational moire

Abstract: Design of equilateral hyperbolic zone plate moire pattern formed by a mutual rotation of two basic grids is studied in detail. The advantages of this zone plate moire pattern are analysed in comparison with solutions for other moire zone plates. Two most important advantages are: a constant aperture of the element during the mutual rotation of basic grids and a lack of aberrations due to their undesired displacements. The applicability of considered moire pattern for the three point alignment technique is mentioned.