Blood Microcirculation Velocimetry Based On Video

Microcirculation is very important for oxygen and material exchange and transport in tissues and organs. Blood velocity provides valuable information on the function and dynamics of microcirculation.Capillary is classified into two groups by diameter in our work. Correlation is used to measure the velocity of blood flow with small diameter. It has been a long time on blood velocity measurement[9] of this type. There are many methods to obtain the windows. But the intensity signal obtained from the windows isn't accuray of some methods or the real time property is not very good of others. Capillary is segmented accurately by adopting digital signal processing in this paper. And window's orientation is the same as the blood flow's. The measurement can be used in real time.It is more complex of the capillary with large diameter. They are classified into three types. For the first type, blood and tissue are very complex (fig. 3.1). Some of them are much similar. The characteristics of this type are as follow. The speed is very low. The edge of a group of blood is visible and easy to track. There is little distortion of the shape of a group of blood between two frames. There are many methods to measure blood velocity such as optical flow techniques[40,44,45], using fluorescent images[42], template matching method[17] and so on[43]. Template matching method is adopted in this paper. The algorithm's speed is improved using blood flow's characters in this paper. It can be used in real time situation. For the second type, the blood flow's speed is very high(fig.3.5). Average speed of a frame can be measured using FFT. For the third type, the blood's speed is very fast in a frame and maybe very slow in the next frame. It is difficult to measure the velocity using a standard video system but can be measured with high-speed video camera system[17,42,43].Many knowledge such as digital image processing, digital signal processing and graphics are used in this project. The software is developed by visual c++.