Enhanced two-frequency phase-shifting method

Hyun, Jae-Sang; Zhang, Song

doi:10.1364/ao.55.004395

Cited by 104 publications

(51 citation statements)

References 12 publications

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“…As for the dual-frequency phase unwrapping method, the low frequency phase is scaled up by the scaling factor 1 2 / f f to determine the fringe order. Therefore, to reduce the noise, the low frequency phase is represented by more than one period of fringes (25,27). After extract the wrapped phases corresponding to the high and low frequency components, the minimum phase map created using geometric constraint of the digital fringe projection (DFP) is employed to unwrap the low frequency phase intricately.…”

Section: Yun's Methodsmentioning

confidence: 99%

Enhanced dual-frequency pattern scheme based on spatial-temporal fringes method

Wang

Zhou

et al. 2018

Journal of Modern Optics

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One of the major challenges of employing a dual-frequency phase-shifting algorithm for phase retrieval is its sensitivity to noise. Yun et. al [H Yun, B Li, S Zhang. 2017] proposed a dual-frequency method based on the Fourier transform profilometry (FTP), yet the low frequency lobes are close to each other for accurate band-pass filtering. In light of this problem, a novel dual-frequency pattern based on the spatial-temporal fringes (STF) method is developed in this paper. Three fringe patterns with two different frequency are required. The low frequency phase is obtained from two low frequency fringe patterns by the STF method, so the signal lobes can be extracted accurately as they are far away from each other. The high frequency phase is retrieved from another fringe pattern without the impact of the DC component. Simulations and experiments are conducted to demonstrate the excellent precision of the proposed method.

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Section: Yun's Methodsmentioning

confidence: 99%

Enhanced dual-frequency pattern scheme based on spatial-temporal fringes method

Wang

Zhou

et al. 2018

Journal of Modern Optics

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“…The conventional dual-frequency phase unwrapping algorithm use the continuous phase of the low-frequency fringe to unwrap the wrapped phase of the high-frequency one [15][16]. Assuming that the frequency of the low-frequency fringe…”

Section: Zhang's Methodsmentioning

confidence: 99%

“…It is very expensive computationally. Zhang [15] proposed an enhanced two-frequency phase-shifting method. Similar to reference [14], the low-frequency fringe patterns are not with a unit frequency, so the phase of the low-frequency fringe patterns is wrapped.…”

Section: Introductionmentioning

confidence: 99%

“…this method needs to calibrate the DFP system, calculate min system, so the actual operation is relatively complex, (2) since geometric constraints can be used to unwrap the low-frequency wrapped phase, could it be directly used to unwrap the high-frequency one? Based on our analysis of the work reported in Ref [15],. we propose an improved phase-unwrapping method using geometric constraints, and the fundamental idea is that the complex procedure of calibrating the DFP system and calculating min is replaced by the simple experiment.…”

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confidence: 99%

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Improved phase-unwrapping method using geometric constraints

Wang

Zhou

et al. 2017

Journal of Modern Optics

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Conventional dual-frequency fringe projection algorithm often suffers from phase unwrapping failure when the frequency ratio between the high frequency and the low one is too large. Zhang et.al. proposed an enhanced two-frequency phase-shifting method to use geometric constraints of digital fringe projection(DFP) to reduce the noise impact due to the large frequency ratio. However, this method needs to calibrate the DFP system and calculate the minimum phase map min  at the nearest position from the camera perspective, these procedures are are relatively complex and more time-cosuming. In this paper, we proposed an improved method, which eliminates the system calibration and min  determination in Zhang's method,meanwhile does not need to use the low frequency fringe pattern. In the proposed method,we only need a set of high frequency fringe patterns to measure the object after the high frequency min  is directly estimated by the experiment. Thus the proposed method can simplify the procedure and improve the speed. Finally, the experimental evaluation is conducted to prove the validity of the proposed method.The results demonstrate that the proposed method can overcome the main disadvantages encountered by Zhang's method.

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“…Instead of creating a vector for each (u, v), we create a vector for each (u new , v new ), and the conditions to discard a 3D point is the same as Eq. (16). If the occluded points are far away from the front point, such as those points between EF on Fig.…”

Section: Invisible 3d Point Cullingmentioning

confidence: 99%

High-resolution, real-time simultaneous 3D surface geometry and temperature measurement

Zhang

2016

Opt. Express

Self Cite

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This paper presents a method to simultaneously measure three-dimensional (3D) surface geometry and temperature in real time. Specifically, we developed 1) a holistic approach to calibrate both a structured light system and a thermal camera under exactly the same world coordinate system even though these two sensors do not share the same wavelength; and 2) a computational framework to determine the sub-pixel corresponding temperature for each 3D point as well as discard those occluded points. Since the thermal 2D imaging and 3D visible imaging systems do not share the same spectrum of light, they can perform sensing simultaneously in real time: we developed a hardware system that can achieve real-time 3D geometry and temperature measurement at 26 Hz with 768 × 960 points per frame.

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Enhanced two-frequency phase-shifting method

Cited by 104 publications

References 12 publications

Enhanced dual-frequency pattern scheme based on spatial-temporal fringes method

Enhanced dual-frequency pattern scheme based on spatial-temporal fringes method

Improved phase-unwrapping method using geometric constraints

High-resolution, real-time simultaneous 3D surface geometry and temperature measurement

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