A digital moiré fringe method for displacement sensors

  • Jian Wu
  • Ting-ting Zhou
  • Bo YuanEmail author
  • Li-qiang Wang


In this study, a displacement measurement method based on digital moiré fringe is described and experimentally demonstrated. The method is formed by only one grating with a constant pitch. First, the magnified grating image is received by an imaging array and is sent to a computer. Then, the digital moiré fringes are generated by overlaying the grating image with its mirrored one. Finally, a specifically designed algorithm is used to obtain the fringes’ phase difference before and after movement and calculate the displacement. This method has the effects of amplifying displacement and averaging the grating lines error, the same as the traditional moiré technique using two pieces of gratings. At the same time, the proposed system is much easier to assemble and the measurement resolution can be set more flexibly. One displacement measuring system based on this method was built up. Experiment results show that its measurement errors are less than 0.3 μm and less than 0.12 μm at the resolutions of 0.1 μm and 0.03 μm, respectively.


Digital moiré fringe Displacement measurement Grating 

CLC number

TH741 TN911.7 


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Copyright information

© Journal of Zhejiang University Science Editorial Office and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Jian Wu
    • 1
  • Ting-ting Zhou
    • 1
  • Bo Yuan
    • 1
    Email author
  • Li-qiang Wang
    • 1
  1. 1.State Key Laboratory of Modern Optical Instrumentation, CNERC for Optical InstrumentZhejiang UniversityHangzhouChina

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