Dual-frequency fringe Fourier transform profilometry based on defocusing

Fu, Yanjun; Wang, Yong-Long; Wu, Jianfeng; Jiang, Guangyu

doi:10.1016/j.optcom.2013.01.013

Cited by 15 publications

(9 citation statements)

References 20 publications

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“…This, together with the fact the strength of these peaks decreases roughly as 1/|k mn |, limits the aliasing artifacts discussed in the previous section. The strength of the secondary peaks can be further reduced by slightly defocussing the pattern, which effectively acts as an optical low-pass filter [27,28,29].…”

Section: Methodsmentioning

confidence: 99%

Real-time quantitative Schlieren imaging by fast Fourier demodulation of a checkered backdrop

Wildeman

2018

Exp Fluids

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A quantitative synthetic Schlieren imaging (SSI) method based on fast Fourier demodulation is presented. Instead of a random dot pattern (as usually employed in SSI), a 2D periodic pattern (such as a checkerboard) is used as a backdrop to the refractive object of interest. The range of validity and accuracy of this "Fast Checkerboard Demodulation" (FCD) method are assessed using both synthetic data and experimental recordings of patterns optically distorted by small waves on a water surface. It is found that the FCD method is at least as accurate as sophisticated, multi-stage, digital image correlation (DIC) or optical flow (OF) techniques used with random dot patterns, and it is significantly faster. Efficient, fully vectorized, implementations of both the FCD and DIC/OF schemes developed for this study are made available as open source Matlab scripts.

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Section: Methodsmentioning

confidence: 99%

Real-time quantitative Schlieren imaging by fast Fourier demodulation of a checkered backdrop

Wildeman

2018

Exp Fluids

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“…The effect is same to Eqs. (6)(7)(8)(9)(10)(11). Calculating partial derivatives in fringe domain is replaced with a simple procedure in Fourier spectrum space.…”

Section: Theorymentioning

confidence: 99%

“…Canabal [6] employed a temporal phase unwrapping (TPU) method to adjust the sensibility of the measurement and obtain more accurate results. Fu [7] used a defocusing method to generate dual-frequency fringe to improve the accuracy. Wang [8] combined the optimal pulse width modulation (OPWM) method with the error-diffusion dithering method using the binary defocusing technique to achieve superfast absolute shape measurement.…”

Section: Introductionmentioning

confidence: 99%

Improved differential 3D shape retrieval

Liu

Zhou

et al. 2015

Optics and Lasers in Engineering

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“…A vital step in FPP is calibration, which determines the relationship between the unwrapped phase and the height of the object [16][17][18][19]. The main methods utilized to measure complex surfaces are Gray code plus phase-shifting method [20], dual-frequency FPP [21], multi-frequency FPP [22], and so on [23]. Zhang presented a twofrequency binary phase-shifting technique to achieve the 3D shape of complex surfaces; however, the measurement accuracy of this method is not sufficiently high [24].…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional shape measurement of complex surfaces based on defocusing and phase-shifting coding

Wang

et al. 2015

Journal of Modern Optics

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2015): Three-dimensional shape measurement of complex surfaces based on defocusing and phase-shifting coding, Journal of Modern Optics, Binary fringe defocused projection is a promising method for high-speed, high-accuracy three-dimensional (3D) shape measurement because of the advantages of superfast projection and capability to overcome the nonlinear gamma of the projector. However, the application of this approach for complex surface measurement remains a challenge. Thus, a method that combines binary fringe and phase coding fringe based on defocusing is proposed to achieve fast-speed, high-accuracy 3D shape measurement of complex surfaces. However, in the case of defocusing, as the number of phase coding fringe cycles increases, the fringe order k(x, y) becomes difficult to judge, errors occur in the jump area, and the periodic dislocation problem becomes worse, ultimately leading to phase unwrapping error. A phase-shifting coding method is thus presented to resolve these issues. This method not only alleviates the difficulty in judging the fringe order as a result of defocusing but also resolves the correction problem, and in turn, the periodic dislocation problem. Thus, measurement accuracy is improved. Experimental results demonstrate the feasibility and superiority of the proposed method.

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Dual-frequency fringe Fourier transform profilometry based on defocusing

Cited by 15 publications

References 20 publications

Real-time quantitative Schlieren imaging by fast Fourier demodulation of a checkered backdrop

Real-time quantitative Schlieren imaging by fast Fourier demodulation of a checkered backdrop

Improved differential 3D shape retrieval

Three-dimensional shape measurement of complex surfaces based on defocusing and phase-shifting coding

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