Figure 6. 3D particle tracking in a microchannel.

The red particles form a filter cake. The circles and lines mark the positions and jumps of the tracked particle, respectively. The color of the tracer particle depicts its z-height in the channel (from bottom/low: dark blue to top/high: green). Stationary particles and a second tracked particle are masked for clarity. The channel walls are indicated as a guide to the eye. The original video can be found as Supplementary Video 2.