Error suppression for speckle correlation-based 3D shape measurement via dynamic shape function selection

A three-dimensional (3D) shape measurement method based on binary fringe conventional projection is proposed. In traditional 3D shape measurement methods based on binary fringe projection, the binary fringe is used as an approximate sinusoidal fringe by defocusing projection or even directly used as an approximate sinusoidal fringe by nonlinear error suppression feature of large-step phase measuring profilometry (PMP). In the proposed method (Prop), neither defocusing projection is needed nor large-step PMP must be used. When the binary fringe is conventionally projected on the measured object, just by filtering operation in spatial frequency domain from the captured deformed pattern, the nearly unbroken sinusoidal deformed pattern can be extracted efficiently. While N ( N≥3) frames binary fringes with 1/ N period misalignment between each adjacent fringe are conventionally projected onto the measured object sequentially, the corresponding nearly unbroken N-step sinusoidal deformed patterns extracted from the N frames captured deformed patterns can be used to reconstruct the 3D shape of the measured object with N-step PMP algorithm. The experimental results show the feasibility and validity of the Prop. It is more flexible for its optional fringe period and optional phase-shifting steps. It has potential application in the real-time 3D shape measurement.

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Learning-based absolute 3D shape measurement based on single fringe phase retrieval and speckle correlation

Optical Metrology and Inspection for Industrial Applications VII ◽

10.1117/12.2573817 ◽

2020 ◽

Author(s):

Wei Yin ◽

Chao Zuo ◽

Shijie Feng ◽

Tianyang Tao ◽

Qian Chen

Keyword(s):

Phase Retrieval ◽

Shape Measurement ◽

3D Shape ◽

3D Shape Measurement ◽

Speckle Correlation

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3D Shape Measurement Based on Digital Speckle Projection and Spatio-Temporal Correlation

Proceedings ◽

10.3390/icem18-05437 ◽

2018 ◽

Vol 2 (8) ◽

pp. 552

Author(s):

Qican Zhang ◽

Renchao Xu ◽

Yihang Liu ◽

Zhenyi Chen

Keyword(s):

Correlation Method ◽

Temporal Correlation ◽

Shape Measurement ◽

Digital Speckle Correlation Method ◽

3D Shape ◽

3D Shape Measurement ◽

Speckle Correlation ◽

Digital Speckle ◽

Spatio Temporal ◽

Digital Speckle Correlation

With the non-periodicity and discrete nature, and unnecessary of phase unwrapping process, digital speckle correlation method shows its significant advantages in three-dimensional (3D) shape measurement. Combining with the spatial correlation and temporal correlation method in the digital speckle correlation, a spatio-temporal digital speckle correlation was developed in this paper, which can improve the accuracy of 3D shape measurement and effectively reduce the number of the recorded speckle images for restoring the corresponding 3D shape at the same time. In the experiment, only 5 frames of the required speckle images was needed to reconstruct the 3D shape of a complex object with spatio-temporal digital speckle correlation method, and its accuracy was same as the result when 20 frames speckle images were used in temporal correlation method.

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