Super-Resolution Particle Tracking Velocimetry

Digital particle image velocimetry (DPIV) is a quantitative flow visualization technique that uses digitally recorded video images to measure the velocity field of fluid flows (Willert and Gharib, 1991). In a typical DPIV application, the flow field is seeded with small particles, a planar region of interest is illuminated with a laser sheet, and images are recorded onto videodisk. Displacement data are recovered from the captured image by locating the peak of the cross-correlation between small portions of the image. The spatial resolution of conventional DPN is thus limited to the order of the interrogation window's size, typically 32x32 pixels. In this paper, we report on the development of an image analysis technique that uses a combination of cross-correlation, pattern recognition, and particle tracking to improve the spatial resolution of DPIV to the mean distance between particles. We refer to this a super-resolution particle tracking velocimetry.