10 August 2020 Phase-measuring profilometry of colored objects based on color coding and sinusoidal correction
Zhongyi Bao, Hongru Li, Han Yuan, Lei Cui, Shouhuan Zhou
Author Affiliations +
Abstract

To improve the phase-measuring profilometry measurement speed, phase-shifted fringes can be encoded into color channels. However, for colored objects, the intensity of the fringes in each channel is affected by surface texture. Therefore, a measurement method based on color coding and sinusoidal correction is proposed. First, two color images are encoded. The red (R) and blue (B) channels for the first image and the green (G) channel for the second image are used in a three-step phase-shifting process. Meanwhile, the G channel of the first coded image and the R and B channels of the second coded image are corresponding solid colors. Two color-coded images are projected onto the object’s surface, and the CCD captures the modulated deformed fringe pattern. After decoupling, the channels of the images are separated, the pure color channels are extracted, and the reflectivity of each point on the object surface in the RGB channels is calculated. Then, the intensity of the phase-shifted fringes in the two images is corrected by the calculated reflectivity. A 24-color standard color card and color lion mask were used to verify the method. Compared with the traditional color coding method, we were able to reduce the influence of color texture and obtain better results.

© 2020 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2020/$28.00 © 2020 SPIE
Zhongyi Bao, Hongru Li, Han Yuan, Lei Cui, and Shouhuan Zhou "Phase-measuring profilometry of colored objects based on color coding and sinusoidal correction," Optical Engineering 59(8), 084101 (10 August 2020). https://doi.org/10.1117/1.OE.59.8.084101
Received: 2 May 2020; Accepted: 21 July 2020; Published: 10 August 2020
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Cited by 2 scholarly publications.
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KEYWORDS
Phase shifts

RGB color model

Reflectivity

Modulation

Charge-coupled devices

Image compression

Optical engineering

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