Moire Analysis of Strain by Fourier Transform

Abstract

By shifting the discrete Fourier spectrum of the image of a deformed grating, we can obtain “the complex moire pattern”. Strain distribution is given as the derivative of the argument of the complex moire pattern. The analysis is completely automatized by introducing the digital image processing. All of the laborious and subjective procedures reguired in conventional analysis such as fringe sign determination, fringe ordering, and fringe interpolation are completely eliminated and objective, fast and accurate analysis can be made. © 1988, The Japan Society of Mechanical Engineers. All rights reserved.