Research on particle image velocimetry based on optical flow

As a new aerodynamics experimental technique,optical flow test technique gradual-ly attracts more and more attention due to its advantages in vector field measurement with pixel scale resolution and strong smoothness ability.By means of scalar constraint equation combined with smoothness constraint condition,optical flow test technique can measure global velocity vec-tor field with high space resolution.In this paper,the integration minimization optical flow ve-locimetry theory and algorithm were firstly studied and programmed by C++;then,in order to verify the accuracy of the optical flow algorithm,three groups of grayscale images shifted by giv-en displacements were used for processing by the optical flow algorithm program and the result can be used to guide how to obtain high-precision optical flow calculation result in the actual measurement applications;at last,backward step verification experiment,in which tracer parti-cle images were acquired by high speed camera and velocity vector field was calculated by optical flow algorithm,was completed in a small wind tunnel.The result calculated by optical flow algo-rithm was compared with the result calculated by PIV′s cross-correlation algorithm,which shows that optical flow test technique possesses the advantages of pixel scale resolution.