OpenPIV is a user-friendly software for Particle Image Velocimetry. It incorporates modules written in Matlab, Python and C++ that allows to estimate the velocity fields from images of particles and post-process the fields to obtain important fluid dynamics quantities such as vorticity, rate-of-strain, dissipation and Reynolds stresses in the case of turbulent flows.
OpenPIV was written in Matlab (tm) in 1998 and was extended using Python and C++ (with Qt4 user interface). OpenPIV is designed to be portable: it supposedly runs on UNIX, Mac and PCs under Windows or Linux.