Machine Vision and Applications

, Volume 10, Issue 4, pp 188–200 | Cite as

A new phase extraction algorithm for phase profilometry

  • Luigi Di Stefano
  • Frank Boland

Abstract.

This paper describes a new phase extraction algorithm for 3D optical profilometry based on the projection of a periodic light pattern and phase measurement (phase profilometry). The algorithm uses a square wave to demodulate phase and moving averages and comb-shaped filters to extract the phase information from low frequency. The proposed algorithm is compared with the two major profilometry techniques, namely Fourier domain profilometry and signal domain profilometry based on FIR low-pass filtering. Comparison is focused on adaptiveness to changes of the pattern frequency, ability to deal with nonuniform surfaces and computational complexity. Adaptiveness analysis is carried out by means of simulations. The issue of nonuniform surfaces is discussed on the basis of experimental results obtained from application of phase profilometry to on-line 3D printed circuit board inspection. With regard to complexity, theoretical estimates are verified by means of actual computation time measurements.

Key words:3D optical profilometry – Active ranging – Structured light – Phase profilometry – Automatic inspection 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Luigi Di Stefano
    • 1
  • Frank Boland
    • 2
  1. 1. DEIS, University of Bologna, Viale Risorgimento 2, I-40136 Bologna, Italy; e-mail: ldistefano@deis.unibo.it IT
  2. 2. EEE, University of Dublin, Trinity College, Dublin 2, Ireland; e-mail: fboland@ee.tcd.ie IE

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