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.

Spectral analysis of moire images

Abstract: The signal-to-noise ratio of moire images is quite low. Obtaining useful information from an image can often be probiematic, since the contrast of the grid giving rise to the moire phenomena is similar to the contrast of the moire fringes that carry the useful information. By using optical filtering techniques it is possible to filter these images real-time. In this paper the authors give an example of an algorithm to design an appropriate spatial filter by comparing the Fourier spectra of a mathematical model of a moire image with a real moire image.

Projection moire for 3D inspection of printed circuit boards

Abstract: We present a method of projection moire specially devised for the three-dimensional inspection of printed circuit boards. This method incorporates phase-shifting technique in analyzing moire fringes so as to achieve a fine resolution of 1 micron in height measurement. Further a synchronous grating translation scheme enhances the lateral measuring resolution by inherently removing the original pattern of the reference grating in resulting moire fringes. Finally we discuss the advantages of the proposed method using several measurement results performed on the various types of solder paste silk-screened on printed circuit boards.

Capturing apparatus and method for capturing images without moire pattern

Abstract: An method for capturing images using a capturing apparatus including determining whether a moire pattern exists in a preview image captured by a camera device. A capturing parameter of the camera device is adjusted when the moire pattern exists in the preview image. The camera device is controlled to capture images when the capturing parameter has been adjusted.

Deformation measurement method, deformation measurement device, and program therefor

Abstract: This deformation measurement method for measuring deformation generated in a specimen when a load is applied to the specimen, comprises: recording images of a cyclic pattern on a surface of the specimen by use of an image recording means before and after first-time load application to the specimen after preparation of the specimen; generating moire fringes on the basis of the recorded images of the cyclic pattern; calculating the phase of the moire fringes before the first-time load application to the specimen; calculating the phase of the moire fringes after the first-time load application to the specimen; obtaining the phase difference between the moire fringes before and after the load application to the specimen; and calculating a deformation distribution and a strain distribution of the specimen by applying two-dimensional phase simultaneous analysis to the phase difference. In a case where the residual strain is measured, even a grating image after release of the residual stress is recorded, moire fringes are generated, the phase difference between the moire fringes after release of the residual stress and the moire fringes before the first-time load application is obtained, and a residual strain distribution of the specimen is calculated by application of two-dimensional phase simultaneous analysis to the phase difference.