A Sampled-Grating Model of Moire Patterns from Digital Imaging

Abstract

Traditional 'crossed-grating' moire, as well as newer 'sampled-grating' (scanning) moire, have proven to be effective methods of shape measurement. There is speculation that the moire patterns of a sampled grating, which are due to aliasing, can be modeled with crossed gratings. We compare the two and show that while crossed gratings can correctly predict the frequencies of a sampled grating, they cannot correctly predict the amplitudes. We go on to formulate a new model which accounts for multiple stages of sampling and transmission, and show how neglecting multiple stages can lead to mistakes in moire analysis. We demonstrate our model with an experiment using a digital imaging system. (RRH)

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Jul 01, 1989
Accession Number
ADA213364

Entities

People

  • John Krumm
  • Steven Arthur Shafer

Organizations

  • Carnegie Mellon University

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Birds
  • Cameras
  • Charge Coupled Devices
  • Contracts
  • Diffraction
  • Digital Cameras
  • Digital Images
  • Engineering
  • Fourier Series
  • Frequency
  • Geometry
  • Jet Propulsion
  • Measurement
  • Spectra
  • Square Waves
  • Standards
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Computational Modeling and Simulation
  • Image Processing and Computer Vision.
  • Optical Physics and Photonics.