Improved Ternary Gray-Code Phase Unwrapping Algorithm for 3D Measurement Using a Binary Defocusing Technique

By using one-bit binary patterns instead of eight-bit sinusoidal ones, the binary defocusing techniques have been widely applied for high-speed 3D shape measurement. As projector defocusing is required, the phase unwrapping process of these techniques remains challenging. A recently proposed ternary Gray-code method can effectively increase the measurement speed by reducing the number of acquired coding patterns. However, it still has limitations, including the measuring range and a noise problem. To improve these, a new ternary Gray-code method is proposed by utilizing 2D modulation instead of the 1D modulation used in the conventional method. Simulations were conducted to compare these two methods, and the results verify that the proposed method reduces the variance in the introduced intermediate gray value by nearly 90%. Experiments were also carried out with the results verifying the superiority of the proposed method.

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Two 3D spatial phase unwrapping algorithms for dynamic 3D shape measurement

Journal of Modern Optics ◽

10.1080/09500340.2020.1862331 ◽

2020 ◽

pp. 1-13

Author(s):

Yifan Feng ◽

Yu Han ◽

Qican Zhang

Keyword(s):

Phase Unwrapping ◽

Shape Measurement ◽

3D Shape ◽

Spatial Phase ◽

3D Shape Measurement

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High-speed 3D shape measurement by one pitch phase analysis method using brightness values in small square area of single-shot image

Optics and Lasers in Engineering ◽

10.1016/j.optlaseng.2018.08.023 ◽

2019 ◽

Vol 113 ◽

pp. 38-46 ◽

Cited By ~ 5

Author(s):

Yoshiharu Morimoto ◽

Akihiro Masaya ◽

Masaki Ueki

Keyword(s):

Phase Analysis ◽

High Speed ◽

Shape Measurement ◽

Single Shot ◽

Analysis Method ◽

3D Shape ◽

3D Shape Measurement

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3D shape measurement with temporal phase unwrapping and 1-D continuous wavelet transform

Photonic Instrumentation Engineering VIII ◽

10.1117/12.2593776 ◽

2021 ◽

Author(s):

Susana L. Burnes-Rudecino ◽

José de Jesús Villa Hernández ◽

Gamaliel Moreno ◽

Ismael de la Rosa ◽

Efrén González ◽

...

Keyword(s):

Wavelet Transform ◽

Continuous Wavelet Transform ◽

Phase Unwrapping ◽

Shape Measurement ◽

Continuous Wavelet ◽

3D Shape ◽

3D Shape Measurement ◽

Temporal Phase

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Fast 3D Shape Measurement of Complex Objects Combining S-transform Profilometry and Sub-Pixel Refinement

10.21203/rs.3.rs-38856/v1 ◽

2020 ◽

Author(s):

Feng Lu ◽

Jikun Yang

Keyword(s):

Fringe Pattern ◽

Vision System ◽

Phase Unwrapping ◽

Shape Measurement ◽

Complex Objects ◽

3D Shape ◽

3D Shape Measurement ◽

Phase Slope ◽

S Transform ◽

Hybrid Function

Abstract In the fast 3D shape measurement of complex objects, the process of phase unwrapping affects the measurement accuracy and measurement speed. To omit phase unwrapping, a fast 3D shape measurement method is proposed based on S-transform profilometry and sub-pixel refinement. In this work, Deformed fringe pattern is analyzed based on S-transform to get wrapped phase. To reduce the effect of phase unwrapping, a stereo vision system is employed. Firstly, a deformed fringe pattern is directly used and a hybrid function is proposed to get an initial parallax. Secondly, a phase slope algorithm is proposed to confirm edge point. At last, sub-pixel parallax is refined fromIcoordinate. Experiments are carried out to verify the feasibility and advantage of the proposed method. Results verify that the proposed method can provide fast and accurate 3D shape measurement of complex objects, especially for discontinuous objects and shiny objects.

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High Speed 3D Shape Measurement with Temporal Fourier Transform Profilometry

Applied Sciences ◽

10.3390/app9194123 ◽

2019 ◽

Vol 9 (19) ◽

pp. 4123 ◽

Cited By ~ 3

Author(s):

Haihua Zhang ◽

Qican Zhang ◽

Yong Li ◽

Yihang Liu

Keyword(s):

Fourier Transform ◽

High Speed ◽

Shape Measurement ◽

Measurement Technology ◽

Reconstruction Process ◽

Measured Object ◽

3D Shape ◽

3D Shape Measurement ◽

Fourier Transform Profilometry ◽

Dynamic Objects

A novel high-speed 3D shape measurement technology called temporal Fourier transform profilometry (TFTP for short) is proposed by combining the merits of Fourier transform profilometry (FTP) and phase-measuring profilometry (PMP). Instead of using the digital light projector, a mechanical projector is employed to generate multi-period phase-shifting fringe patterns sequentially. During the reconstruction process, the phase value of each pixel is calculated independently along the temporal axis and no spectrum filtering operation is performed in a spatial domain. Therefore, high-frequency components containing the detailed information of the measured object effectively remain. The proposed method is suitable for measuring isolated dynamic objects. Only one frame of deformed fringe pattern is required to retrieve one 3D shape of the measured object, so it has the obvious advantage if measuring the dynamic scene at a high speed. A low-cost self-made mechanical projector with fast projection speed is developed to execute the principle-proof experiments, whose results demonstrate the feasibility of measuring isolated dynamic objects.

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