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Nonlinearity correction in digital fringe projection profilometry by using histogram matching technique

Digital fringe projection profilometry employs a digital video projector as a structured light source and thus gains great flexibility. However, the luminance nonlinearity of the video projector may decrease measurement accuracy and resolution. To overcome this problem, we propose a nonlinearity correction technique for digital fringe projection profilometry. This technique allows determining the response curve of a digital video projector by matching the histogram of the fringe images with that of a standard sinusoid signal. By iterating the two steps, histogram matching and phase evaluation, the phase distribution of the fringe pattern is finally solved with higher accuracy. In so doing, neither photometric calibration nor knowledge about the device is required. Both computer simulation and experiment are carried out to demonstrate the validity of this technique.