Rainbow particle imaging velocimetry for dense 3d fluid velocity imaging

Abstract

Imaging of complex, non-stationary three dimensional (3D) flow velocities is achieved by encoding depth into color. A flow volumeis illuminated with a continuumof light planeswhereby each depth corresponds to a respective light planehaving a specific wavelength of light. A diffractive componentin the cameraoptics, which records the trajectories of illuminated particleswithin the flow volume, ensures that all light planesare in focus simultaneously. The setup permits a user to track 3D trajectories of particleswithin the flow volumeby combining two dimensional (2D) spatial and one dimensional (1D) color information. For reconstruction, an image formation model for recovering stationary 3D particle positions is provided. 3D velocity estimation is achieved with a variant of a 3D optical flow approach that accounts for both physical constraints as well as the color (rainbow) image formation model.