scholarly journals A Novel Surface Recovery Algorithm for Dual Wavelength White LED in Vertical Scanning Interferometry (VSI)

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5225
Author(s):  
Linlin Zhu ◽  
Yuchu Dong ◽  
Zexiao Li ◽  
Xiaodong Zhang
Keyword(s):  
White Light ◽  
Gaussian Function ◽  
Three Dimensional ◽  
Reference Points ◽  
Dual Wavelength ◽  
Interference Signal ◽  
Fringe Contrast ◽  
Distinctive Features ◽  
Recovery Algorithm ◽  
Light Interference

The two peaks characteristic of yellow and blue light in the spectrum of dual-wavelength white light emitting diodes (LEDs) introduce distinctive features to the interference signal of white light scanning interferometry (WLSI). The distinctive features are defined as discontinuities, so that the fringe contrast function cannot be modeled as a single Gaussian function, and causes the interferogram to have uneven distribution of fringes of different orders in the scanning interferometer. This phenomenon leads to the low accuracy of the zero-order fringe position in the envelope calculation, which affects the repeatability and accuracy of the interferometry. This paper proposes a new surface recovery algorithm based on the Hilbert phase envelope and adjacent reference points calculation, which can effectively overcome the influence of the discontinuous signal of dual-wavelength LED white light interference on the three-dimensional reconstruction of WLSI measurements. The reliability of the algorithm is verified by experiments, and the measurement accuracy of LED WLSI system is evaluated.

Fast white light interference signal processing method based on effective signal extraction

2019 ◽  
Vol 48 (10) ◽  
pp. 1013002
Author(s):  
马 龙 Ma Long ◽  
贾 竣 Jia Jun ◽  
裴 昕 Pei Xin ◽  
胡艳敏 Hu Yanmin ◽  
周 航 Zhou Hang ◽  
...  
Keyword(s):  
Signal Processing ◽  
White Light ◽  
Processing Method ◽  
Signal Extraction ◽  
Interference Signal ◽  
Light Interference ◽  
Signal Processing Method ◽  
White Light Interference ◽  
Effective Signal

Study on Spatial Frequency Domain Algorithm and White Light Interference System Based on NMM

2015 ◽  
Vol 738-739 ◽  
pp. 904-910
Author(s):  
Li Jian ◽  
Li Hua Lei ◽  
Dong Sheng Li ◽  
Yun Xia Fu ◽  
Yuan Li ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Frequency Domain ◽  
White Light ◽  
Three Dimensional ◽  
Step Height ◽  
Light Interference ◽  
Interference System ◽  
Measuring Machine ◽  
White Light Interference ◽  
Spatial Frequency Domain

White light interference technique for topography measurement effectively avoids phase ambiguity in phase-shifting interferometry. The spatial frequency domain algorithm based on scanning white light interference technique has the advantage of insensitivity to noise and higher calculation accuracy compared with other methods. The white light interference sensor is constructed based on nano positioning and nano measuring machine (NMM), the calibrated step height standard of 100±3nm is measured. The spatial frequency domain algorithm is adopted for data processing, the repetitive test result of 97.9nm and standard deviation of 0.48nm are achieved. To verify the measuring ability of complex device, the number ‘242’ on ink box is measured and three-dimensional reconstruction is conducted. The high precision and traceable measurements of micro/nano scale step height standard and complex devices are realized by the white light interference system based on NMM with steady frequency laser interferometer built-in.

A robust white-light interference signal leakage sampling correction method based on wavelet transform

2020 ◽  
Vol 133 ◽  
pp. 106156 ◽  
Author(s):  
Lei Xin ◽  
Zhenhua Liu ◽  
Jiantai Dou ◽  
Zhongming Yang ◽  
Xingyu Zhang ◽  
...  
Keyword(s):  
Wavelet Transform ◽  
White Light ◽  
Correction Method ◽  
Interference Signal ◽  
Light Interference ◽  
White Light Interference

scholarly journals Filtering Biomechanical Signals in Movement Analysis

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4580
Author(s):  
Francesco Crenna ◽  
Giovanni Battista Rossi ◽  
Marta Berardengo
Keyword(s):  
Measurement Uncertainty ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Movement Analysis ◽  
Analytical Signal ◽  
Human Movement ◽  
Reference Points ◽  
Biomechanical Analysis ◽  
Method Performance ◽  
Acceleration Signal

Biomechanical analysis of human movement is based on dynamic measurements of reference points on the subject’s body and orientation measurements of body segments. Collected data include positions’ measurement, in a three-dimensional space. Signal enhancement by proper filtering is often recommended. Velocity and acceleration signal must be obtained from position/angular measurement records, needing numerical processing effort. In this paper, we propose a comparative filtering method study procedure, based on measurement uncertainty related parameters’ set, based upon simulated and experimental signals. The final aim is to propose guidelines to optimize dynamic biomechanical measurement, considering the measurement uncertainty contribution due to the processing method. Performance of the considered methods are examined and compared with an analytical signal, considering both stationary and transient conditions. Finally, four experimental test cases are evaluated at best filtering conditions for measurement uncertainty contributions.

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