Measuring Particle Flow by Voronoï Diagrams

Vanderdonckt, Jean [UCL] Soares Frazao, Sandra [UCL] Zech, Yves [UCL] Villarreal Narvaez, Santiago [UCL]

A Particle-Trajectory Velocity (PTV) of moving particles can be analyzed by a digital imaging method based on the Voronoï diagram, which is the dual of the Delaunay triangulation. While this technique has been already applied in various fields, such as homogeneous fluidization, uniform debris flow, this paper adapts and applies this technique to the area of very small moving particles, such as in spermocytogram, as follows: 1) A high-resolution microscope acquires a video sequence of the moving particles; 2) Image segmentation is achieved by detecting discrete particles in each image based on the position of their center; 3) A Voronoï diagram determines the influence zones of each particle at time t and t+dt 4) A correspondence is established between the two images at time t and t+dt 5) The velocity is calculated on this basis.