Single-camera 3D PTV using particle intensities and structured light

Abstract

We use structured monochromatic volume illumination with spatially varying intensity profiles, to achieve 3D intensity particle tracking velocimetry using a single video camera. The video camera records the 2D motion of a 3D particle field within a fluid, which is perpendicularly illuminated with depth gradients of the illumination intensity. This allows us to encode the depth position perpendicular to the camera, in the intensity of each particle image. The light intensity field is calibrated using a 3D laser-engraved glass cube containing a known spatial distribution of 1100 defects. This is used to correct for the distortions and divergence of the projected light. We use a sequence of changing light patterns, with numerous sub-gradients in the intensity, to achieve a resolution of 200 depth levels.

TomoFluid: Reconstructing Dynamic Fluid From Sparse View Videos

“…in the fluid, then the velocity of the fluid is retrieved by tracking these tracers. Particle Image Velocimetry (PIV) and its different variants, such as tomographic PIV [15], synthetic aperture PIV [6], structured-light PIV [48,47,1] and plenoptic PIV [16,41] are widely used in different fields to characterize fluid flows. For tracer-free approaches like Background Oriented Schlieren tomography (BOS) [19,4], the phase change due refractive index differences in the fluid to track the flow.…”

Stereo Event-Based Particle Tracking Velocimetry for 3D Fluid Flow Reconstruction

“…Moreover, at each time only one depth layer is scanned. More sophisticated techniques that can resolve 3D volumes include holographic PIV [43,29], defocusing digital PIV [47,48,71], synthetic aperture PIV [6], tomographic PIV (tomo-PIV) [18,61], structured-light PIV [70,69,2], and plenoptic (light-field) PIV [19,66,42]. These approaches can be multi-view based, like the widely used tomo-PIV.…”

“…To solve this issue, several variants of PIV have been proposed to extend the velocity retrieval to the third spatial dimension (a detailed discussion about such techniques is provided in the next section). Overall, these techniques can be regrouped into two families: multiple-cameras based approaches like tomographic PIV (tomo-PIV) [18,61] and single-camera based techniques such as light-field (or plenoptic) PIV [19,66,42] or structured-light PIV [70,69,2]. Among these, tomo-PIV is considered the established reference technology for the velocity 3D measurement, since it provides high spatial and temporal resolutions.…”

Visualization of the Strain-Rate State of a Data Cloud: Analysis of the Temporal Change of an Urban Multivariate Description

“…One is the vector plot of three-dimensional displacements or velocities, which is typically used to visualize results in computational mechanics applications [3][4][5]. For example, these methods are used in the kinematic visualization of motion [6][7][8][9][10], but they are restricted to display the relative motion among the data, and are not able to identify the most dynamic regions of the dataset. Another is the parallel coordinate technique that successfully exhibits the temporal change of highly-dimensional statistical and information datasets [11].…”