Single-shot phase measuring profilometry based on color binary grating with intervals

Abstract

A single-shot phase measuring profilometry (PMP) based on color binary grating with intervals is proposed. In traditional PMP based on binary grating, the width for non-zero transmittance of the binary grating is always 1/2 periods rigorously. In our proposed method, a color binary grating is introduced in which three binary gratings with the same period and the same width for non-zero transmittance less than 1/3 periods are misaligned 1/3 periods one another and programmed in red (R), green (G) and blue (B) channels respectively. Because the widths for non-zero transmittance in R, G and B channels of the introduced color binary grating are all less than 1/3 periods and misaligned 1/3 periods one another, the color overlap can be avoided from the source. When measuring the object, only a single-shot deformed pattern needs to be captured and three nearly unbroken sinusoidal deformed patterns with an equivalent phase-shifting of 2π∕3 can be extracted from R, G and B components of the captured color deformed pattern. So the 3D shape of the measured object can be successfully reconstructed with three-step PMP. Experiment results show the feasibility of the proposed method. Due to its single-shot feature, it is promising to measure the dynamic objects.