Laser-based volumetric colour-coded three-dimensional particle velocimetry

McGregor, T.J.; Spence, David J.; Coutts, David W.

doi:10.1016/j.optlaseng.2007.01.009

Cited by 35 publications

(24 citation statements)

References 30 publications

(36 reference statements)

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“…Instead of modifying the camera side, another class of volumetric particle reconstruction approaches relies on modifying the illumination method, providing additional information on the relative depth, as seen from the camera, by encoding it in color. For this purpose different illumination methods were used: prism [Kimura et 1991], laser [McGregor et al 2007], color filter [Pick and Lehmann 2009], LCD projector [Watamura et al 2013]. Herein, the locations of the particles in the volume can be determined by their 2D spatial positions and by the colors in the captured image using a mapping between color and depth position.…”

Section: Related Workmentioning

confidence: 99%

“…Nevertheless, the presence of random noise, optical aberrations and focus issues, color contamination caused by secondary light scattering from the particles, and color mixing for overlapping particles severely complicate the identification of the representative colors for every possible particle in the observed image. McGregor et al [2007] used a method based on a calibration curve relating the hue of acquired images to the depth of particles within the imaged volume. Watamura et al [2013] proposed an algorithm to calculate particle's representative color by averaging hue values of the pixels where the particle is projected on in polar coordinate.…”

Section: Related Workmentioning

confidence: 99%

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Rainbow particle imaging velocimetry for dense 3D fluid velocity imaging

et al. 2017

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Despite significant recent progress, dense, time-resolved imaging of complex, non-stationary 3D flow velocities remains an elusive goal. In this work we tackle this problem by extending an established 2D method, Particle Imaging Velocimetry, to three dimensions by encoding depth into color. The encoding is achieved by illuminating the flow volume with a continuum of light planes (a "rainbow"), such that each depth corresponds to a specific wavelength of light. A diffractive component in the camera optics ensures that all planes are in focus simultaneously. With this setup, a single color camera is sufficient for tracking 3D trajectories of particles by combining 2D spatial and 1D color information. For reconstruction, we derive an image formation model for recovering stationary 3D particle positions. 3D velocity estimation is achieved with a variant of 3D optical flow that accounts for both physical constraints as well as the rainbow image formation model. We evaluate our method with both simulations and an experimental prototype setup.

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Section: Related Workmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

Rainbow particle imaging velocimetry for dense 3D fluid velocity imaging

et al. 2017

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“…In the recent past, many methods were proposed to access volumetric information from 3D flow fields. This was achieved using holographic measurements (Hinsch 2002;Sheng et al 2008), by combining PIV with Doppler global velocimetry (PIV/DGV) (Wernet 2004), using tomography (Elsinga et al 2006;Schröder et al 2008), defocusingbased approaches (Pereira et al 2000(Pereira et al , 2007Willert and Gharib 1992), scanning-light-sheet methods (Burgmann et al 2008;Hoyer et al 2005;Brücker 1995), color-coded depth resolving techniques (Zibret et al 2003;McGregor et al 2007) and absorption-based methods (Jehle and Jähne, 2008;Berthe et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Bichromatic particle streak velocimetry bPSV

et al. 2012

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We propose a novel technique for threedimensional three-component (3D3C) interfacial flow measurement. It is based on the particle streak velocimetry principle. A relatively long integration time of the camera is used for capturing the movement of tracer particles as streaks on the sensor. The velocity along these streaks is extracted by periodically changing the illumination using a known pattern. A dye with different absorption characteristics in two distinct wavelengths is used to color the fluid. The depth of particles relative to the fluid interface can then be computed from their intensities when illuminated with light sources at those two different wavelengths. Hence, from our approach, a bichromatic, periodical illumination together with an image processing routine for precisely extracting particle streak features is used for measuring 3D3C fluid flow with a single camera. The technique is applied to measuring turbulent Rayleigh-Bénard convection at the free air-water interface. Using Lagrangian statistics, we are able to demonstrate a clear transition from the Batchelor regime to the Richardson regime, both of which were postulated for isotropic turbulence. The relative error of the velocity extraction of our new technique was found to be below 0.5 %.

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“…The measured color variable K as a function of wavelength is shown in Fig. We have previously shown 24 that by using the standard definition of hue in place of K, the Foveon™ X3 provides an average wavelength precision limit of ϳ1 nm. Calibration measurements show that for the Sigma SD10 camera, K is approximately irradiance-independent throughout two orders of magnitude dynamic range of the 12 bit digitized sensor range, resulting in a precision limit of Ͻ0.75 nm across the spectral range from 500 to 660 nm.…”

Section: A Choice Of Color Variablementioning

confidence: 99%

“…We recently used a multiwavelength source generated by Raman conversion of a copper vapor laser 24 ͑CVL͒ to encode a measurement volume. We recently used a multiwavelength source generated by Raman conversion of a copper vapor laser 24 ͑CVL͒ to encode a measurement volume.…”

Section: Introductionmentioning

confidence: 99%

Laser-based volumetric flow visualization by digital color imaging of a spectrally coded volume

McGregor

Spence

Coutts

2008

Review of Scientific Instruments

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We present the framework for volumetric laser-based flow visualization instrumentation using a spectrally coded volume to achieve three-component three-dimensional particle velocimetry. By delivering light from a frequency doubled Nd:YAG laser with an optical fiber, we exploit stimulated Raman scattering within the fiber to generate a continuum spanning the visible spectrum from 500 to 850 nm. We shape and disperse the continuum light to illuminate a measurement volume of 20 x 10 x 4 mm(3), in which light sheets of differing spectral properties overlap to form an unambiguous color variation along the depth direction. Using a digital color camera we obtain images of particle fields in this volume. We extract the full spatial distribution of particles with depth inferred from particle color. This paper provides a proof of principle of this instrument, examining the spatial distribution of a static field and a spray field of water droplets ejected by the nozzle of an airbrush.

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Laser-based volumetric colour-coded three-dimensional particle velocimetry

Cited by 35 publications

References 30 publications

Rainbow particle imaging velocimetry for dense 3D fluid velocity imaging

Rainbow particle imaging velocimetry for dense 3D fluid velocity imaging

Bichromatic particle streak velocimetry bPSV

Laser-based volumetric flow visualization by digital color imaging of a spectrally coded volume

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