Advanced algorithms for microscale particle image velocimetry

The recent explosive increase in the use of fluidic microelectromechanical systems (MEMS) has subsequently driven the development of fluidic measurement techniques capable of measuring velocities at length scales small enough to be of use in characterizing and optimizing these new devices. Recently, several techniques have demonstrated spatial resolutions smaller than 100 mum but larger than 10 mum. These techniques include x-ray microimaging, molecular tagging velocimetry, and microlaser Doppler velocimetry. However, measurements with spatial resolutions smaller than 10 mum are necessary for making measurements in many MEMS applications. Only micro-particle image velocimetry has demonstrated this high spatial resolution, By the use of a combination of advanced imaging and processing techniques that are described here, spatial resolutions on the order of single micrometers can be achieved. These techniques are used to investigate the flow though a microfabricated thruster geometry.