Precise and fast phase wraps reduction in fringe projection profilometry

Wang, Minmin; Du, Guangliang; Zhou, Changli; Si, Shuchun; Lei, Zhenkun; Li, Xiaolei; Li, Yanjie

doi:10.1080/09500340.2017.1322719

Cited by 4 publications

(3 citation statements)

References 28 publications

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“…Then to reallocate the low (or zero) frequency to the center can make a screen more attractive and this is what we anticipate. To attain 2D (I x J image) SFFT transformation [21], this is the shifting encoder which can be defined as presented in (5).…”

Section: Shifted Fft (Sfft)mentioning

confidence: 99%

Evaluation of graphic effects embedded image compression

Jittawiriyanukoon¹,

Srisarkun²

2020

IJECE

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A fundamental factor of digital image compression is the conversion processes. The intention of this process is to understand the shape of an image and to modify the digital image to a grayscale configuration where the encoding of the compression technique is operational. This article focuses on an investigation of compression algorithms for images with artistic effects. A key component in image compression is how to effectively preserve the original quality of images. Image compression is to condense by lessening the redundant data of images in order that they are transformed cost-effectively. The common techniques include discrete cosine transform (DCT), fast Fourier transform (FFT), and shifted FFT (SFFT). Experimental results point out compression ratio between original RGB images and grayscale images, as well as comparison. The superior algorithm improving a shape comprehension for images with grahic effect is SFFT technique.

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Section: Shifted Fft (Sfft)mentioning

confidence: 99%

Evaluation of graphic effects embedded image compression

Jittawiriyanukoon¹,

Srisarkun²

2020

IJECE

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“…However, the disadvantage associated with windowing is amplitude compression at both ends, which causes degradation in the quality of phase at ends, especially if the signal is very noisy [19]. Another method is the extension of the boundaries of the fringe pattern using the zero padding, but this makes the process computationally complex and time consuming [20].…”

Section: Introductionmentioning

confidence: 99%

Carré Phase Shifting Algorithm for Wavelength Scanning Interferometry

et al. 2022

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Wavelength scanning interferometry is an interferometric technique for measuring surface topography without the well-known 2π phase ambiguity limitation. The measurement accuracy and resolution of this technique depends, among other factors, on the algorithm used to evaluate its sinusoidal interference pattern. The widely used fast Fourier transform analysis experiences problems such as waviness error across the measured surface due to spectral leakage. This paper introduces a new fringe analysis method based on the Carré phase shifting algorithm combined with a least squares fitting approach. Numerical simulation was carried out to assess the performance of the Carré algorithm in comparison to fast Fourier transform analysis, and the same was validated by presenting four experimental case study examples (a surface flat, a ceramic ball bearing, a flexible thin film, and a discontinuous step height sample). The analysis results show that the proposed Carré algorithm with least squares fitting can significantly eliminate the waviness error, especially when measuring steep surfaces.

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“…Wang et al presented a fast two-step method to reduce the phase wraps. In their method, a frequency peak was calculated first using an FFT, and then, the sub-pixel spectral peak was determined by applying a discrete Fourier transform to the iteratively up-sampled area around the initial frequency peak location [16]. High accuracy and efficiency can be achieved based on their method.…”

Section: Introductionmentioning

confidence: 99%

Improved Carrier Frequency-Shifting Algorithm Based on 2-FFT for Phase Wrap Reduction

Zhang

Wang

et al. 2021

Mathematical Problems in Engineering

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The number of phase wraps that result from the carrier component can be completely eliminated or reduced by first applying a fast Fourier transform (FFT) to the image and then shifting the spectrum to the origin. However, because the spectrum can only be shifted by an integer number, the phase wraps of the carrier component cannot be completely reduced. In this paper, an improved carrier frequency-shifting algorithm based on 2-FFT for phase wrap reduction is proposed which allows the spectrum to be shifted by a rational number. Firstly, the phase wraps are reduced by the conventional FFT frequency shift method. Secondly, the wrapped phase with residual carrier components is filtered and magnified sequentially; the amplified phase is transformed into the frequency domain using an FFT, and then, the wrapped phase with the residual carrier components can be further reduced by shifting the spectrum by a rational number. Simulations and experiments were conducted to validate the efficiency of the proposed method.

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Precise and fast phase wraps reduction in fringe projection profilometry

Cited by 4 publications

References 28 publications

Evaluation of graphic effects embedded image compression

Evaluation of graphic effects embedded image compression

Carré Phase Shifting Algorithm for Wavelength Scanning Interferometry

Improved Carrier Frequency-Shifting Algorithm Based on 2-FFT for Phase Wrap Reduction

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