The Robotics Institute

Carnegie Mellon Robotics Institute

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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 gating, 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.

Notes

Associated Center(s) / Consortia: Vision and Autonomous Systems Center

Associated Lab(s) / Group(s): Calibrated Imaging Lab

Text Reference

John Krumm and Steven Shafer, "A Sampled-grating Model of Moire Patterns from Digital Imaging," tech. report CMU-RI-TR-89-19, Robotics Institute, Carnegie Mellon University, July, 1989

BibTeX Reference

@techreport{Krumm_1989_201,
   author = "John Krumm and Steven Shafer",
   title = "A Sampled-grating Model of Moire Patterns from Digital Imaging",
   booktitle = "",
   institution = "Robotics Institute",
   month = "July",
   year = "1989",
   number= "CMU-RI-TR-89-19",
   address= "Pittsburgh, PA",
}

The Robotics Institute

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