Particle streak velocimetry-optical coherence tomography: a novel method for multidimensional imaging of microscale fluid flows

Biomed Opt Express. 2016 Mar 30;7(4):1590-603. doi: 10.1364/BOE.7.001590. eCollection 2016 Apr 1.

Abstract

We present a new OCT method for flow speed quantification and directional velocimetry: particle streak velocimetry-OCT (PSV-OCT). PSV-OCT generates two-dimensional, 2.5-vector component (vx ,|vy |,vz ) maps of microscale flow velocity fields. Knowledge of 2.5-vector components also enables the estimation of total flow speed. The enabling insight behind PSV-OCT is that tracer particles in sparsely-seeded fluid flow trace out streaks in (x,z,t)-space. The streak orientations in x-t and z-t yield vx and vz , respectively. The in-plane (x-z plane) residence time yields the out-of-plane speed |vy |. Vector component values are generated by fitting streaks to a model of image formation that incorporates equations of motion in 3D space. We demonstrate cross-sectional estimation of (vx ,|vy |,vz ) in two important animal models in ciliary biology: Xenopus embryos (tadpoles) and mouse trachea.

Keywords: (110.4153) Motion estimation and optical flow; (110.4500) Optical coherence tomography; (120.7250) Velocimetry; (170.3880) Medical and biological imaging; (280.2490) Flow diagnostics.