Miniature particle image velocimetry system withLED in-line illumination

Abstract

For two decades, there has been active research toenhance the performance of particle image velocimetry (PIV)systems. However, the resulting systems are rathercostly, cumbersome and delicate. In this paper, we address thedesign and some first experimental results of a PIV systembelonging to the opposite paradigm. The miniature PIV or MPIVsystem features relatively modest performance. For example, ourMPIV prototype has a field of view of 6 mm×5 mm andcan measure about 50 velocity vectors for liquid flows slowerthan 1 m s-1. However, it is considerably smaller (our MPIVcould be held in ⌀40 mm×120 mm),cheaper (our MPIV total cost is less than $500), easy to handleand less hazardous (accidental exposure of the eyes to thestrobe light). Potential applications include industrialvelocity sensors.The proposed MPIV system uses a one-chip-only CMOS camera withdigital output. Only two other chips are needed, one for abuffer memory and one for an interfacing logic that controls thesystem. Images are transferred to a personal computer viaits standard parallel port. No extra hardware is required (inparticular, no frame grabber board is needed). In the MPIVprototype presented in this paper, a ring of 12 super-brightLEDs in line with the optical axis is used as a strobe light in aforward-scatter configuration. Experimental results arepresented and discussed.