Subnanometer Translation of Microelectromechanical Systems Measured by Discrete Fourier Analysis of CCD Images

Abstract—In-plane linear displacements of microelectromechanical systems are measured with subnanometer accuracy by observing the periodic micropatterns with a charge-coupled device camera attached to an optical microscope. The translation of the microstructure is retrieved from the video by phase-shift computation using discrete Fourier transform analysis. This approach is validated through measurements on silicon devices featuring steep-sided periodic microstructures. The results are consistent with the electrical readout of a bulk micromachined capacitive sensor, demonstrating the suitability of this technique for both calibration and sensing. Using a vibration isolation table, a standard deviation of σ = 0.13 nm could be achieved, enabling a measurement resolution of 0.5 nm (4σ) and a subpixel resolution better than 1/100 pixel. [2010-0170

Patterned probes for high precision 4D-STEM bragg measurements.

Nanoscale strain mapping by four-dimensional scanning transmission electron microscopy (4D-STEM) relies on determining the precise locations of Bragg-scattered electrons in a sequence of diffraction patterns, a task which is complicated by dynamical scattering, inelastic scattering, and shot noise. These features hinder accurate automated computational detection and position measurement of the diffracted disks, limiting the precision of measurements of local deformation. Here, we investigate the use of patterned probes to improve the precision of strain mapping. We imprint a "bullseye" pattern onto the probe, by using a binary mask in the probe-forming aperture, to improve the robustness of the peak finding algorithm to intensity modulations inside the diffracted disks. We show that this imprinting leads to substantially improved strain-mapping precision at the expense of a slight decrease in spatial resolution. In experiments on an unstrained silicon reference sample, we observe an improvement in strain measurement precision from 2.7% of the reciprocal lattice vectors with standard probes to 0.3% using bullseye probes for a thin sample, and an improvement from 4.7% to 0.8% for a thick sample. We also use multislice simulations to explore how sample thickness and electron dose limit the attainable accuracy and precision for 4D-STEM strain measurements

Computer vision and optimization methods applied to the measurements of in-plane deformations

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Fundamental remote sensing science research program. Part 1: Status report of the mathematical pattern recognition and image analysis project

The Mathematical Pattern Recognition and Image Analysis (MPRIA) Project is concerned with basic research problems related to the study of the Earth from remotely sensed measurement of its surface characteristics. The program goal is to better understand how to analyze the digital image that represents the spatial, spectral, and temporal arrangement of these measurements for purposing of making selected inference about the Earth

Točna 3D rekonstrukcija zasnovana na rotirajućoj platformi i telecentričnoj viziji

This paper presents a camera+telecentric lens that is able to obtain 3D information. We designed and implemented a method which can register and integrate 3D information captured from different viewpoints to build a complete 3D object model. First, a geometric model of a camera+telecentric lens is established. Then a calibration process using a planar checkerboard is developed and implemented. The object is placed on a rotation stage in front of a stationary camera. Normally the rotation axis is considered to be aligned with camera frame. In the description presented in this paper, the rotation matrix and translation vector of the rotation axis are calibrated. At the same time, a three-dimensional reconstruction system based on contour extraction of objects with dimensions less than 50 mm in diameter is developed. Finally, an analysis of the uncertainty model parameters and performance reconstruction of 3D objects are discussed.Članak prestavlja sustav koji se sastoji od kamere i telecentrične leće koji omogućavaju dobivanje 3D informacije o objektu. Dizajnirana je i implementirana metoda koja može registrirati i integrirati 3D informacije iz različitih točaka gledišta, kako bi se izgradio potpuni 3D model. Na početku, uspostavlja se geometrijski model kamere i telecentrične leće. Nakon toga koristi se razvijena metoda kalibracije zasnovana na šahovskoj ploči te se objekt postavlja na rotirajuću platformu ispred stacionarne kamere. Također, pretpostavlja se da je os rotacije poravnta s koordinantim sustavom kamere. U ovome članku kalibriraju se rotacijska matrica i translacijski vektor rotacijske osi. Razvijen je i sustav 3D rekonstrukcija zasnovan na izlučivanju kontura objekta dimenzija manjih od 50 mm u promjeru. Na kraju, provedena je i analiza nesigurnosti parametara modela kao i točnost rekonstrukcije 3D modela