High speed fringe projection for dynamic shape measurement using binary phase mask. Part 1: theory and simulation
Projection rates of up to 30,000 greyscale fringe patterns per second have been achieved recently by defocusing binary fringe patterns from a digital micromirror device (DMD) based projector. Part 1 of this two-part paper describes the design of a binary phase mask, based on a virtual scatter plate, for the purpose of enhancing the performance of a binary fringe projector. The phase mask's anisotropic point spread function (PSF) produces a well-defined blur of the fringes parallel to the fringe direction, thereby minimising degradation of fringe contrast. The shape of the PSF is also shown, by means of a polychromatic Fourier optics model, to be insensitive to projection distance over a range of ±10% of the standoff distance. Two new binary fringe design methods are proposed, including extensions to optimize the system performance in the case of a mismatch between camera and projector framing rates. Expressions for the phase noise are derived as a function of the phase mask design parameters, which demonstrate that fringe quality comparable to traditional 8-bit greyscale fringes is achievable at projection rates over two orders of magnitude higher.
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- Mechanical, Electrical and Manufacturing Engineering
Published inOptics and Lasers in Engineering
- VoR (Version of Record)
Rights holder© The Authors
Publisher statementThis is an Open Access Article. It is published by Elsevier under the Creative Commons Attribution 4.0 International Licence (CC BY 4.0). Full details of this licence are available at: https://creativecommons.org/licenses/by/4.0/