A PIV algorithm is presented for estimating time-averaged or phase-averaged velocity
fields. The algorithm can be applied to situations where signal strength is not sufficient
for standard cross correlation techniques, such as a low number of particle images in an
interrogation spot, or poor image quality. The algorithm can also be used to increase the
spatial resolution of measurements by allowing smaller interrogation spots than those
required for standard cross correlation techniques. The quality of the velocity measurements
can be dramatically increased by averaging a series of instantaneous correlation
functions, before determining the location of the signal peak, as opposed to the commonly
used technique of estimating instantaneous velocity fields first and then averaging the
velocity fields. The algorithm is applied to a 30 mm3300 mm microchannel flow.