21 March 2018 Nonlinear gamma correction via normed bicoherence minimization in optical fringe projection metrology
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Abstract
We propose a method to compensate for the projector intensity nonlinearity induced by gamma effect in three-dimensional (3-D) fringe projection metrology by extending high-order spectra analysis and bispectral norm minimization to digital sinusoidal fringe pattern analysis. The bispectrum estimate allows extraction of vital signal information features such as spectral component correlation relationships in fringe pattern images. Our approach exploits the fact that gamma introduces high-order harmonic correlations in the affected fringe pattern image. Estimation and compensation of projector nonlinearity is realized by detecting and minimizing the normed bispectral coherence of these correlations. The proposed technique does not require calibration information and technical knowledge or specification of fringe projection unit. This is promising for developing a modular and calibration-invariant model for intensity nonlinear gamma compensation in digital fringe pattern projection profilometry. Experimental and numerical simulation results demonstrate this method to be efficient and effective in improving the phase measuring accuracies with phase-shifting fringe pattern projection profilometry.
© 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)
Abel Kamagara, Xiangzhao Wang, Sikun Li, "Nonlinear gamma correction via normed bicoherence minimization in optical fringe projection metrology," Optical Engineering 57(3), 034107 (21 March 2018). https://doi.org/10.1117/1.OE.57.3.034107 . Submission: Received: 21 November 2017; Accepted: 27 February 2018
Received: 21 November 2017; Accepted: 27 February 2018; Published: 21 March 2018
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