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.

Deformation measurement method not affected by microscope scan distortion due to secondary moire fringe

Abstract: PROBLEM TO BE SOLVED: To solve the problem that a distortion of scan line of a scan type microscope causes distortion of moire fringes to bring about an error in deformation measurement that uses moire, and in a phase shift method that removes distortion, an analysis range becomes narrower because a grid itself must be photographed, and further, in a case where a device itself is shifted for phase shifting, a device is required and is expensive.SOLUTION: A technique that utilizes secondary moire fringe (Secondary Moire) in which two images having been photographed before and after deformation of a sample are synthesized so that scan moire fringes are superposed each other so that an effect of scan distortion is eliminated for measurement of sample deformation, has been developed.SELECTED DRAWING: Figure 3

Moire reduction using inflection point in frequency domain

Abstract: Digital still cameras generally use an optical low-pass filter(OLPF) to enhance the image quality by removing high spatial frequencies causing aliasing. While eliminating the OLPF can save manufacturing costs, images captured without using an OLPF include moire in the high spatial frequency region of the image. Therefore, to reduce the presence of moire in a captured image, this paper presents a moire reduction method without the use of an OLPF. First, the spatial frequency response(SFR) of the camera is analyzed and moire regions detected using patterns related to the SFR of the camera. Using these detected regions, the moire components represented by the inflection point between the high frequency and DC components in the frequency domain are selected and then removed. Experimental results confirm that the proposed method can achieve moire reduction while preserving detail information.

Moire technique- based measurement of the 3-dimension profile of a specimen and its implementation with line-scan camera

Abstract: Disclosed are a moire 3D shape measuring apparatus of a line scan mode and an apparatus thereof The moire 3D shape measuring apparatus of the line scan mode includes: a lattice projection unit which comprises a light source, an illumination lens, a projection lattice, a projection lens, and a fine projection lattice transfer device for projecting the lattice image on the surface of a test object; an object unit which is provided to mount the test object and comprises a x-y transfer table to move the test object along an x-y plane; and a focusing unit which includes a focusing lens to focus the lattice image reflected from the surface of the test object and a line scan camera which includes a linear image pickup device inside

Dynamic Shape and Strain Measurements of Rotating Tire in Time-Series

Abstract: Shape measurement and strain distribution measurement are important to analyze the behavior of a rotating tire. A dynamic shape and strain measurement system by the sampling moire method was developed. Recently, phase analysis method using phase-shifting moire patterns generated in a computer from a grating image is proposed. This method is very suitable for dynamic measurement because the phase can be obtained from a one-dimensional or two-dimensional grating image with high accuracy. It is possible to analyze strain distribution and shape measurement of a moving object using a grating pattern attached on the specimen surface. A dynamic shape and strain measurement system by the sampling moire method is developed. In this paper, we applied high-speed cameras to this method. The behavior when a tire got over a projection with high-speed rotating was observed as time-series data. The principle and experimental results are shown.