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.

X-ray imaging system and image processing device

Abstract: An X-ray imaging system includes an X-ray imaging device and an image processing device including a reconstruction unit and an estimation unit. The X-ray imaging device uses a Talbot or Talbot-Lau interferometer including gratings disposed in a line. The X-ray imaging device obtains sets of moire fringe images by fringe scanning multiple times between which arrangement of the gratings is changed. In the fringe scanning, one of the gratings is moved relatively to the remaining grating. The reconstruction unit generates, on the basis of the sets, a reconstructed image which is a differential phase image, an X-ray absorption image and/or a small-angle scattering image. The estimation unit estimates, on the basis of the reconstructed image, a relative position of the moved grating from a reference position of the grating at each imaging in the fringe scanning.

Automated In-Plane Moiré Techniques and Grating Interferometry

Abstract: Several problems in experimental solid mechanics and material engineering require determination of in-plane displacement / strain fields It is especially true if we consider flat samples under simple loading arrangement The effective experimental tools working under these assumptions are in-plane grid / moire technique and high sensitivity grating (moire) interferometry Below the principles of both techniques and modern solutions of grating / grid technology and design of moire and interferometric systems are presented As the fringe patterns obtained at the output of the systems require automatic analysis, the overview of the phase methods of fringe pattern analysis especially suited for various opto-mechanical configuration of the systems are described Also the interaction of the results with FEM is presented, while referring to various concepts of hybrid experimental-numerical analysis The result advances in measurement technology expand significantly the applications of the in-plane moire and grating interferometry techniques The numerous examples refer to the most challenging applications including local material constant determination, micromeasurements, residual stress analysis and monitoring of various engineering structures

Moire patterns in disparity measurement

Abstract: Calculating disparity between left and right images is an essential operation in stereo vision. The technique proposed in this paper explores the Moire phenomenon for determining the disparity between regions in two images. Moire patterns are obtained when two similar images are superimposed one on another. Any two images that differ in orientation would still match at the fixed point, according to the Brouwer's theorem. When two images are superimposed the concentric Moire rings point to the location of the fixed point. The location of the fixed point gives the disparity.

Moire Image Restoration using Multi Level Hyper Vision Net

Abstract: A moire pattern in the images is resulting from high frequency patterns captured by the image sensor (colour filter array) that appear after demosaicing. These Moire patterns would appear in natural images of scenes with high frequency content. The Moire pattern can also vary intensely due to a minimal change in the camera direction/positioning. Thus the Moire pattern depreciates the quality of photographs. An important issue in demoireing pattern is that the Moireing patterns have dynamic structure with varying colors and forms. These challenges makes the demoireing more difficult than many other image restoration tasks. Inspired by these challenges in demoireing, a multilevel hyper vision net is proposed to remove the Moire pattern to improve the quality of the images. As a key aspect, in this network we involved residual channel attention block that can be used to extract and adaptively fuse hierarchical features from all the layers efficiently. The proposed algorithms has been tested with the NTIRE 2020 challenge dataset and thus achieved 36.85 and 0.98 Peak to Signal Noise Ratio (PSNR) and Structural Similarity (SSIM) Index respectively.

Diffraction effects in moiré deflectometry: reply to comment

Abstract: We show that placing the object in front of the gratings, as in moire deflectometry, rather than between them (as inTalbot interferometry) makes moire deflectometry capable of providing fully quantitative analyses of arbitrary objects. In addition, we review some differences in the philosophical aspects between the two methods (viz., ray approach versus wave interference).