Profile measurements using contrast-encoded pattern projections

Cheng, Nai–Jen; Chen, Sih-Yue; Su, Wei‐Hung

doi:10.1117/12.2530714

Cited by 1 publication

(3 citation statements)

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“…The duty cycle ω 0 /T generally maintains 1/2 but can be 1/3 or else. The color binary fringe projection (CBF) proposed by Fu et al [24]. Three monochromatic binary fringes occupy 1/3 period, respectively, and are arranged periodically.…”

Section: Principle 21 the Quaternary Grating Design Principlementioning

confidence: 99%

“…However, to capture the fringe images, a color CCD must be adopted, and generally the frame capturing rate may be limited. The color binary fringe projection (CBF) proposed by Fu et al [24]. Three monochromatic binary fringes occupy 1/3 period, respectively, and are arranged periodically.…”

Section: Principle 21 the Quaternary Grating Design Principlementioning

confidence: 99%

“…Su et al proposed a one-shot projected fringe profilometry using a 2D fringe-encoded pattern, and the fringe pattern used for phase extraction can be directly utilized for unwrapping, but the accuracy of this method is limited by the FTP algorithm [23]. Cheng et al [24] designed a contrast encoded pattern with a quaternary contrast-encoded scheme for phase-shifting techniques, however, three sinusoid quaternary contrast-encoded pattern are necessary to reconstruct the 3D profile of an object. Chen et al [25] introduced a quantized phase-coding method to generate more than 36 different three-digit codes to achieve a high measurement accuracy, but the measurement speed was also limited by three fringe pattern projection.…”

Section: Introductionmentioning

confidence: 99%

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Single-Shot Phase Measuring Profilometry Based on Quaternary Grating Projection

2021

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In this paper, we propose a new single-shot three-dimensional (3D) measuring method based on quaternary grating projection. In traditional binary grating phase measuring profilometry (PMP), a multi-step or color fringe pattern are usually used to extract the sinusoidal fringes. In our proposed method, by using the DLP4500′s 2-bit gray coding mode, the grayscale is quaternary. The three non-zero grayscales cyclically arranged in equal width, and the fourth grey value is 0 which is not encoded in the fringe pattern but represents the shadow information in the deformed pattern, where a quaternary grating is encoded. When the DLP4500 projects the quaternary grating onto the measured object, the charge coupled device (CCD) captures the corresponding deformed pattern synchronously. Three frames of binary deformed patterns with 1/3 duty cycle and a relative displacement of 1/3 period can be decomposed by the segmentation algorithm proposed in this paper. Three sinusoidal deformed patterns with a 2π/3 shift-phase can be obtained by extracting the fundamental frequency of the three binary deformed patterns correspondingly, and the 3D shape of the object can be reconstructed by PMP. Experimental results show the effectiveness and feasibility of the proposed method. Because the DLP4500 only needs 2-bit coded grating for projection, the refresh rate of the projected grating is as high as 1428 Hz, which will have a broad application prospect in real time and fast online measurement.

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Section: Principle 21 the Quaternary Grating Design Principlementioning

confidence: 99%

Section: Principle 21 the Quaternary Grating Design Principlementioning

confidence: 99%