Sampled-grating and crossed-grating models of moire patterns form digital imaging
Abstract
Traditional "crossed-grating" moire as well as the newer "sampled-grating" (scanning) moire have proved 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 by writing notationally consistent models of each and show that while crossed gratings can correctly predict the frequencies of a sampled grating, they cannot correctly predict the amplitudes. Our sampled-grating model is a new formulation that accounts for multiple stages of sampling and transmission. We show how neglecting multiple stages can lead to mistakes in moire analysis. We demonstrate our models with an experiment using a digital imaging system.
BibTeX
@article{Krumm-1991-13211,author = {John Krumm and Steven Shafer},
title = {Sampled-grating and crossed-grating models of moire patterns form digital imaging},
journal = {Optical Engineering},
year = {1991},
month = {February},
volume = {30},
number = {2},
pages = {195 - 206},
}