Multi-Angle Digital Holographic Profilometry for Precision Measurements

A novel digital holographic interferometry used for measuring the 3D shape is proposed. The theory analysis and simulation of multi-angle interferometry are described. General holographic interferometry are not able to measure the discontinuous object because of the phase unwrapping. However, in this method, holographic interferograms are generated by object beam and reference beam with different incident angles. Height information of every point at the object surface is extracted independently without the phase unwrapping. The results of simulation demonstrate that this method can be used for measuring the complicated and discontinuous object. It will be useful for the measuring the large and complex discontinuous surfaces often exist in mechanical machining.

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Novel Method of Digital Holographic Profilometry

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1006-1007.857 ◽

2014 ◽

Vol 1006-1007 ◽

pp. 857-862

Author(s):

Qing Chen Bao ◽

Shu Hai Jia ◽

Yong Xu ◽

Chao Jiang

Keyword(s):

Low Cost ◽

Measurement Techniques ◽

Reference Beam ◽

Phase Unwrapping ◽

Shape Measurement ◽

Object Beam ◽

3D Shape ◽

3D Shape Measurement ◽

Continuous Object ◽

Novel Method

The 3D shape measurement has been one of research hotspots in the field of Mechanical measurement. But general optical 3D shape measurement techniques can only measure the continuous object through the phase unwrapping. It’s very difficult to unwrap the phase of the discontinuous object. To solve this problem, a novel digital holographic interferometry used for measuring the 3D shape is proposed in this paper. In this method, holographic interferograms are generated by object beam and reference beam at different incident angles. Height information of every point at the object surface is extracted independently without the phase unwrapping, thus it can measure the discontinuous object. The simulation and initial experiment results suggest that the method is completely feasible and low-cost, so it has great potential to apply in the industrial production.

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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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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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