Two-dimensional scanning laser slope gauge: measurements of ocean-ripple structures

Li, Qingxiong; Zhao, Meng; Tang, Shiue–Cheng; Shi-cai, Sun; Wu, Jin

doi:10.1364/ao.32.004590

Cited by 12 publications

(3 citation statements)

References 10 publications

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“…The output data of deflectometry is also in the form of slopes that are widely used in shape metrology for industrial inspection and surface topography [4][5][6][7]. Thus, we need to convert the measured slopes to the wavefront or surface shape to be estimated; this should be carefully dealt with since it influences the measurement accuracy.…”

Section: Introductionmentioning

confidence: 99%

Improving wavefront reconstruction accuracy by using integration equations with higher-order truncation errors in the Southwell geometry

Liu

et al. 2013

J. Opt. Soc. Am. A

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Least-squares (LS)-based integration computes the function values by solving a set of integration equations (IEs) in LS sense, and is widely used in wavefront reconstruction and other fields where the measured data forms a slope. It is considered that the applications of IEs with smaller truncation errors (TEs) will improve the reconstruction accuracy. This paper proposes a general method based on the Taylor theorem to derive all kinds of IEs, and finds that an IE with a smaller TE has a higher-order TE. Three specific IEs with higher-order TEs in the Southwell geometry are deduced using this method, and three LS-based integration algorithms corresponding to these three IEs are formulated. A series of simulations demonstrate the validity of applying IEs with higher-order TEs in improving reconstruction accuracy. In addition, the IEs with higher-order TEs in the Hudgin and Fried geometries are also deduced using the proposed method, and the performances of these IEs in wavefront reconstruction are presented.

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Section: Introductionmentioning

confidence: 99%

Improving wavefront reconstruction accuracy by using integration equations with higher-order truncation errors in the Southwell geometry

Liu

et al. 2013

J. Opt. Soc. Am. A

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“…Besides, there are also a few researches focusing on the liquid surface wave damping [9,10]. For instance the laserscanning slope technique is applied to study the LSW at a low frequency (a few hertz), because the LSW wavelength is much greater than the scanning laser diameter in the case [11][12][13][14]. The imaging analyzer is used to study LSW at a few tens hertz, and the image is formed by the light transmitted through the dyed liquid medium [15,16].…”

Section: Introductionmentioning

confidence: 99%

Measurement of the damping of liquid surface wave by diffraction method

Dong¹,

Qi²,

Miao³

2007

Braz. J. Phys.

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A simple method for measuring the damping of the liquid surface wave (LSW) based on the diffraction method was proposed in this paper. In the experiment, the phenomenon was observed that the intensity distribution of the diffraction patterns from the LSW varies with the position of the incident spot. By theoretical analysis of the relationship between the intensity distribution and the LSW amplitude, the damping constant was obtained. In addition, the viscosity of the liquid can be calculated with this method, too.

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“…Also, these gauges are in direct contact with the flow field means the flow field disturbance is frequently unavoidable ( Hernández et al, 2018;Liu et al, 1982;Lee & Wang, 1984;Yao & Wu, 2005). Optical sensors (Blenkinsopp et al, 2012;Li et al, 1993;Payne et al, 2009), ultrasonic sensors (Blenkinsopp et al, 2010;Vousdoukas et al, 2014) have been used to evaluate the water surface elevation. To overcome the limitations of the intrusive methods, nonintrusive image-based techniques have been developed to obtain the water surface elevation (Douglas et al, 2020;Escudero et al, 2021;Hernández-Fontes et al, 2020;Hernández et al, 2018;Iglesias et al, 2009;Yao & Wu, 2005).…”

mentioning

confidence: 99%

An intermediate water gravity wavelength and wave height measurement inside a large wave flume tank

Aldarabseh

Merati

2023

JART

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This paper discusses an intermediate water gravity wavelength and wave height measurement method. Three methods were used to obtain wave height, wavelength, and period. Firstly, conventional methods used two Honeywell pressure sensors mounted at the bottom of the wave tank at two different locations. Secondly, using the transfer function of the flap wavemaker (the relationship between wave height and the wave paddle stroke). Thirdly, the Laser Sheet technique (PIV image processing technique). The significant wave height and period from pressure reading sensors of regular gravity waves were obtained from the Raleigh distribution and Zero up crossing technique. Wavelength was obtained indirectly by using a dispersion relationship that was solved by using the Newton Raphson numerical method from both the pressure sensors and the transfer function of the flap wavemaker. This experiment was focused on getting the direct value of wave measurements by developing an image processing technique in a clear large wave flume tank to replace the conventional methods and eliminate the error that may produce by using the numerical methods. The PIV setup with the CCD camera was used to capture wave images. The image processing technique based on Canny edge detection with constant threshold value was used to detect the edge of the waves. The experimental result showed a good agreement between the results obtained from these three methods, with the percent of error up to 8.683%.

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Two-dimensional scanning laser slope gauge: measurements of ocean-ripple structures

Cited by 12 publications

References 10 publications

Improving wavefront reconstruction accuracy by using integration equations with higher-order truncation errors in the Southwell geometry

Improving wavefront reconstruction accuracy by using integration equations with higher-order truncation errors in the Southwell geometry

Measurement of the damping of liquid surface wave by diffraction method

An intermediate water gravity wavelength and wave height measurement inside a large wave flume tank

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