A Study On The Technology Of PIV In Blood Flow Field

Because of age problem and diet change, more and more people suffer from vascular disease, which seriously affects their living standard, sometimes even threatens their lives. Now vascular bypass grafting is a frequent and important surgical procedure to cure vascular diseases and better promote blood supply in the clinical medicine. But the intimal hyperplasia(IH) has been one of the major cause of the graft late failure, especially for the middle and small artery. And recent research shows that the hemodynamic factors have close relation with intimal hyperplasia forming in surgically bypassed arteries. So understanding the feature of blood flow contributes significantly to diagnose the result of transplant and to research and treat vascular diseases。This thesis attaches importance to the research of how to take advantage of particle image velocimetry (PIV) to study blood flow. Eventually we designed the whole measurement system in terms of the features of blood flow.In the first part of this thesis we prove PIV technique is feasible in the research of blood flow field and more convenient compared to doppler technology. Then the three wide used ways in treating flow field pictures including: optical flow tech, feature tracing , model matching were emulated and compared. Furthermore a improved algorithm was got and discussed. This new algorithm can work fast and accurately out the velocity vector field because it combines the advantages of feature tracing and template matching. We analyze and compare two frames to get appropriate speed of key fields. Then two subsequent frames were matched. So the sub-pixel accuracy was obtained by calculation of matching result.