Digital Particle Tracking Velocimetry (DPTV), in contrast, is the low particle concentration mode of DPIV. Since, the required seeding density is lower in comparison with DPIV, tracking the movement of the individual particles (~5 - 50 microns (in air)) within the area of interest yields better results than the conventional statistical analysis methods (auto-correlation / cross-correlation) due to a higher detection rate which can be achieved within the measurement window. The DPTV technique could have an imaging window larger than DPIV because of the sparsely seeded flow. DPTV could arguably yield better positional accuracy than DPIV because it allows one to one tracking of the same particle (centriod) between the two image frames. Particle Tracking Velocimetry can be extended to measure the out-of-plane and in-plane velocity components by using stereo imaging technique.
Grant, I., 1997. Particle image velocimetry: a review, Proc. Instn. Mech. Engrs. Vol 211, Part C, pp.55-76.
A highly versatile but underrated planar (near instantaneous) flow measurement technique. Main interests in the technique are from a few universities and engine manufacturers.