Multi-STFT for adaptive SCPS phase determination

2009 ◽  
Vol 17 (4) ◽  
Author(s):  
R. Sitnik
Keyword(s):  
Fourier Transform ◽  
Carrier Phase ◽  
Fringe Pattern ◽  
Phase Shifting ◽  
Shape Measurement ◽  
Step Method ◽  
Phase Determination ◽  
3D Shape Measurement ◽  
Phase Calculation ◽  
Carrier Phase Shifting

AbstractThis paper presents a fast and reliable approach for phase modulo 2π-calculation from a single fringe pattern. It calculates correct phase values even for very complex and variable shape gradients based on a locally variable fringe period determined for the entire image. In the paper, a new two-step method for wrapped phase calculation is proposed. It is performed through the use of a method based on a multiple local fast Fourier transform for estimation of a local fringes period map and a 5-point spatial carrier phase shifting (SCPS) formula for phase modulo 2π-calculation. The described approach is verified by a correct demodulation of a real fringe pattern taken by a 3D-shape measurement system.

Real-time 3-D shape measurement based on radial spatial carrier phase shifting from circular fringe pattern

2019 ◽  
Vol 450 ◽  
pp. 6-13 ◽  
Author(s):  
Ying Ma ◽  
Da Yin ◽  
Cong Wei ◽  
ShaoTong Feng ◽  
Jun Ma ◽  
...  
Keyword(s):  
Real Time ◽  
Carrier Phase ◽  
Fringe Pattern ◽  
Phase Shifting ◽  
Shape Measurement ◽  
Carrier Phase Shifting

scholarly journals Motion-artifact-free dynamic 3D shape measurement with hybrid Fourier-transform phase-shifting profilometry

2019 ◽  
Vol 27 (3) ◽  
pp. 2713 ◽  
Author(s):  
Jiaming Qian ◽  
Tianyang Tao ◽  
Shijie Feng ◽  
Qian Chen ◽  
Chao Zuo
Keyword(s):  
Fourier Transform ◽  
Motion Artifact ◽  
Phase Shifting ◽  
Shape Measurement ◽  
3D Shape ◽  
3D Shape Measurement ◽  
Fourier Transform Phase ◽  
Free Dynamic

Dynamic microscopic 3D shape measurement based on marker-embedded Fourier transform profilometry

2018 ◽  
Vol 57 (4) ◽  
pp. 772 ◽  
Author(s):  
Yan Hu ◽  
Qian Chen ◽  
Yuzhen Zhang ◽  
Shijie Feng ◽  
Tianyang Tao ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Shape Measurement ◽  
3D Shape ◽  
3D Shape Measurement ◽  
Fourier Transform Profilometry

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

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.

scholarly journals High Speed 3D Shape Measurement with Temporal Fourier Transform Profilometry

2019 ◽  
Vol 9 (19) ◽  
pp. 4123 ◽  
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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