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Dive into the research topics where Yunfei Zhou is active.

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Featured researches published by Yunfei Zhou.


Applied Optics | 2016

Dual-wavelength interferometry based on the spatial carrier-frequency phase-shifting method

Linbo Huang; Xiaoxu Lu; Yunfei Zhou; Jindong Tian; Liyun Zhong

From a single-frame dual-wavelength spatial carrier-frequency interferogram (SCFI), we propose a novel phase retrieval method of dual-wavelength interferometry (DWI). First, by continuously moving the intercepted area pixel-by-pixel in a single-frame SCFI along the horizontal and vertical directions, we construct a sequence of phase-shifting sub-interferograms. Second, the wrapped phases of each single wavelength can be retrieved from those phase-shifting sub-interferograms via the least-squares iteration algorithm. Third, the phase of synthetic wavelength can be obtained by subtraction between the wrapped phases of single wavelengths. Both the numerical simulation and the experimental result demonstrate that the proposed method reveals greater accuracy and convenience. Furthermore, because only single-frame SCFI can perform the phase retrieval of DWI, the proposed method offers better ability in resisting external vibration and disturbance, which will greatly facilitate the application of DWI in the dynamic phase measurement.


Optics Express | 2016

Dynamic phase measurement based on spatial carrier-frequency phase-shifting method.

Linbo Huang; Xiaoxu Lu; Jiaosheng Li; Yunfei Zhou; Jiaxiang Xiong; Jindong Tian; Liyun Zhong

Combining spatial carrier-frequency phase-shifting (SCPS) technique and Fourier transform method, from one-frame spatial carrier-frequency interferogram (SCFI), a novel phase retrieval method is proposed and applied to dynamic phase measurement. First, using the SCPS technique, four-frame phase-shifting sub-interferograms can be constructed from one-frame SCFI. Second, using Fourier transform method, the accurate phase-shifts of four sub-interferograms can be extracted rapidly, so there is no requirement of calibration for the carrier-frequency in advance compared to most existing SCPS methods. Third, the wrapped phase can be retrieved with the least-squares algorithm through using the above phase-shifts. Finally, the phase variations of a water droplet evaporation and a Jurkat cell apoptosis induced by a drug are presented with the proposed method. Both the simulation and experimental results demonstrate that in addition to maintaining high accuracy of the SCPS method, the proposed method reveals more rapid processing speed of phase retrieval, and this will greatly facilitate its application in dynamic phase measurement.


Optics Express | 2017

Improved phase retrieval method of dual-wavelength interferometry based on a shorter synthetic-wavelength

Jiaxiang Xiong; Liyun Zhong; Shengde Liu; Xiang Qiu; Yunfei Zhou; Jindong Tian; Xiaoxu Lu

In dual-wavelength interferometry (DWI), by combing the advantage of the shorter synthetic-wavelength and the immune algorithm of phase ambiguity, we propose an improved phase retrieval method with both high accuracy and large measurement range, which is a pair of contradiction in the reported DWI method. First, we calculate the height of measured object at longer synthetic-wavelength through using the wrapped phases of two single-wavelengths. Second, by combining the immune algorithm of phase ambiguity and the height of measured object at longer synthetic-wavelength, we can perform the phase unwrapping of the larger one of the two single-wavelengths, then achieve accurate height at single-wavelength named as the transition height. Finally, we perform phase unwrapping of shorter synthetic-wavelength through using the immune algorithm of phase ambiguity and the transition height, and then the height at shorter synthetic-wavelength can be achieved. Compared with the reported method, in addition to maintaining the advantage of high accuracy, the proposed method does not need the additional wavelength, so the corresponding measurement procedures is greatly simplified. Simulation and experimental results demonstrate the performance of proposed method.


Optics Express | 2016

Phase retrieval based on temporal and spatial hybrid matching in simultaneous phase-shifting dual-wavelength interferometry.

Xiang Qiu; Liyun Zhong; Jiaxiang Xiong; Yunfei Zhou; Jindong Tian; Dong Li; Xiaoxu Lu

In simultaneous phase-shifting dual-wavelength interferometry, by matching both the phase-shifting period number and the fringe number in interferogram of two wavelengths to the integers, the phase with high accuracy can be retrieved through combining the principle component analysis (PCA) and least-squares iterative algorithm (LSIA). First, by using the approximate ratio of two wavelengths, we can match both the temporal phase-shifting period number and the spatial fringe number in interferogram of two wavelengths to the integers. Second, using above temporal and spatial hybrid matching condition, we can achieve accurate phase shifts of single-wavelength of phase-shifting interferograms through using PCA algorithm. Third, using above phase shifts to perform the iterative calculation with the LSIA method, the wrapped phases of single-wavelength can be determined. Both simulation calculation and experimental research demonstrate that by using the temporal and spatial hybrid matching condition, the PCA + LSIA based phase retrieval method possesses significant advantages in accuracy, stability and processing time.


Scientific Reports | 2017

An advanced phase retrieval algorithm in N-step phase-shifting interferometry with unknown phase shifts

Jiaosheng Li; Liyun Zhong; Shengde Liu; Yunfei Zhou; Jie Xu; Jindong Tian; Xiaoxu Lu

In phase-shifting interferometry with unknown phase shifts, a normalization and orthogonalization phase-shifting algorithm (NOPSA) is proposed to achieve phase retrieval. The background of interferogram is eliminated through using the orthogonality of complex sinusoidal function; and the influence of phase shifts deviation on accuracy of phase retrieval is avoided through both normalization and orthogonalization processing. Compared with the current algorithms with unknown phase shifts, the proposed algorithm reveals significantly faster computation speed, higher accuracy, better stability and non-sensitivity of phase shifts deviation.


Optics Express | 2017

General spatial phase-shifting interferometry by optimizing the signal retrieving function

Yi Wang; Xiang Qiu; Jiaxiang Xiong; Bingbo Li; Liyun Zhong; Shengde Liu; Yunfei Zhou; Jindong Tian; Xiaoxu Lu

A general spatial phase-shifting (GSPS) interferometry method is proposed to achieve phase retrieval from one-frame spatial carrier frequency interferogram. By optimizing the internal signal retrieving function of the spatial phase-shifting (SPS) method, the accuracy, anti-noise ability and speed of phase retrieval can be significantly improved, meanwhile the corresponding local calculation property is reserved. Especially, in the case that the ratio of the spatial carrier to the phase variation rate are small, the proposed method reveals obvious advantage in the accuracy improvement relative to the conventional SPS methods, so the more details of measured sample can be effectively reserved through introducing smaller spatial carrier frequency, and this will facilitate its application in interference microscopy. The principle analysis, numerical simulation and experimental result are employed to verify the performance of the proposed GSPS method.


IEEE Photonics Journal | 2017

A Rapid Spatial Carrier-Frequency Phase-Shifting Method Based on the Orthogonality of Diamond Diagonal Vectors

Xiang Qiu; Liyun Zhong; Bingbo Li; Shengde Liu; Yunfei Zhou; Jiaxiang Xiong; Jindong Tian; Xiaoxu Lu

From a one-frame off-axis interferogram with unknown carrier-frequency, a rapid spatial carrier-frequency phase-shifting (SCFPS) method is proposed to achieve the phase measurement of the dynamic process. First, based on the SCFPS technique, four-frame phase-shifting subinterferograms are constructed from one-frame off-axis interferogram. Second, by using the orthogonality of diamond diagonal vectors, respectively, achieved through the subtraction and addition operations between two equal length vectors, which are generated from above four-frame phase-shifting subinterferograms, the accurate phase can be retrieved rapidly. Compared with current SCFPS methods, in addition to maintaining high accuracy of phase-shifting method, as well as no requirement for carrier-frequency calibration, the proposed method reveals an obvious advantage in processing speed of phase retrieval, and this will greatly facilitate its application prospect for dynamic phase measurement.


IEEE Photonics Journal | 2017

White Light Scanning Interferometry Based on Generalized Cross-Correlation Time Delay Estimation

Yunfei Zhou; Liyun Zhong; Hongzhi Cai; Jindong Tian; Dong Li; Xiaoxu Lu

Based on generalized cross-correlation time delay estimation (GCTDE), a new white light scanning interferometry (WLSI) method is proposed, in which the profile information usually achieved with the zero optical path difference (ZOPD) position is replaced with the relative displacement of interference signal between different pixels. Because all spectral information of interference signal (envelope and phase) and filter is utilized, the proposed GCTDE-based WLSI method reveals the advantages of higher accuracy and better noise suppression capability. Especially, in the case where the shape of interference signal envelope is irregular, the proposed method can achieve profile measurement with high accuracy while the conventional ZOPD position locating method cannot work. Moreover, by introducing laser interferometry system to calibrate the vertical displacement of a piezoelectric ceramic transducer scanning system, the measuring accuracy of the proposed GCTDE-based WLSI is further improved. Both the simulation and the experimental results demonstrate the significant accuracy advantage of the proposed GCTDE-based WLSI.


Scientific Reports | 2018

Dynamic refractive index distribution measurement of dynamic process by combining dual-channel simultaneous phase-shifting interferometry and total internal reflection

Yunfei Zhou; Haoren Zou; Liyun Zhong; Jiaosheng Li; Bingbo Li; Jindong Tian; Xiaoxu Lu

We propose and demonstrate a novel method to measure dynamic refractive index distributions using a combination of total internal reflection (TIR) and dual-channel simultaneous phase-shifting interferometry (DCSPSI). First, a right-angle prism is introduced into the DCSPSI system, the reflection phase variation induced by TIR, which contains the refractive index information of tested sample, can be achieved by the spatial carrier-frequency phase-shifting algorithm from a pair of interferograms with the phase shifts of π/2 captured by DCSPSI system. Second, based on the relationship between the reflection phase variation and the refractive index, the 2D refractive index distribution can be calculated easily. Importantly, the proposed TIR-DCSPSI method will supply a useful tool for dynamic refractive index distribution measurement of dynamic process, such as the droplet evaporation, mutual solubilization and diffusion of different droplets, cell culture, colloid curing, etc.


Journal of Optics | 2017

Rapid phase shifts extraction and phase retrieval by performing 1-norm operation for phase-shifting interferograms

Yunfei Zhou; Junwei Shou; Liyun Zhong; Jiaosheng Li; Shengde Liu; Jindong Tian; Xiaoxu Lu

By performing 1-norm operation for phase-shifting interferograms, a rapid phase shift extraction and phase retrieval algorithm is proposed in random phase-shifting interferometry (PSI). First, by performing the 1-norm operation for a sequence of phase-shifting interferograms, we can construct a group of new interference patterns, possessing less data information but the same phase shifts relative to the original interferograms. Second, based on the least-square iteration (LSI) algorithm, accurate phase shifts can be extracted from these construct interference patterns. Finally, the measured phase can be achieved from the above extracted phase-shifts using the LSI algorithm. The obtained results show that as long as the pixel number of the constructed interference pattern through performing 1-norm operation is about 0.4% pixel number of the original interferogram, the proposed algorithm can achieve accurate phase shifts and be measured. Compared with other iteration algorithms of PSI, in addition to maintaining the advantage of high accuracy, the proposed algorithm reveals outstanding performance in processing speed.

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Liyun Zhong

South China Normal University

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Xiaoxu Lu

South China Normal University

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Jiaxiang Xiong

South China Normal University

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Jiaosheng Li

South China Normal University

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Shengde Liu

South China Normal University

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Xiang Qiu

South China Normal University

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Bingbo Li

South China Normal University

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Hongzhi Cai

South China Normal University

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