Temporal fringe projection profilometry: Modified fringe-frequency range for error reduction

• The modified fringe-phase interval allows the analysis of the fringe image sequence with other signal processing methods. • The modified fringe-phase interval allows considerably reduce measurement errors. • Comparison with outstanding temporal phase-unwrapping methods shows a substantial reduction in measurement error. Temporal techniques for fringe projection profilometry, in particular the multi-frequency class, require the projection of a sequence of fringes with preset frequencies. In this paper, we analyze the generation of fringes that offers better conditions to process them through the modification of the fringe-frequency range, which may reduce measurement errors. This will also serve to expand the possibilities of being able to process the fringe information through different signal-processing methods. Additionally, in this work, we derive a first-approximation frequency-to-height conversion formula and describe an algorithm to process the fringe image sequence through the Continuous Wavelet-Transform (CWT). Experimental results with simulations and real applications are presented as well.