Rearch On Measurement Method Of Hemorheology Based On Linear

Blood viscosity is one of the important parameters that characterize the characteristics of blood rheology,reflects the flow characteristics of the blood.Clinical observation found that high blood pressure,myocardial infarction,ischemic stroke and other diseases in the development process will cause the corresponding increase in blood viscosity value or decrease;headache,dizziness,memory loss and other symptoms,mostly with the increase in blood viscosity and appear,with the blood viscosity decreased and ease.Therefore,the detection of blood viscosity on prevention and early diagnosis of these diseases have an important indication.Medical device of detection blood viscosity called blood rheometer.In this paper,taking into account,the current two mature hemorheology – Cone plate and Pressure type blood rheometer system is relatively complex,longer measurement time,and it is difficult to achieve the characteristics of portability.therefore,study a new type of rheometer to improve the overall performance of the system.This paper introduces the classification and research progress of hemorheology and puts forward a method for measuring viscosity based on blood flow in a capillary :Based on the blood rheology theory of Cardin fluid model,Poisson Law and its correction,the relationship between blood flow velocity and viscosity in capillary is established,and the measurement of viscosity is transferred to the flow rate measurement,which simplifies the system complexity,reduced measurement time.The main process of the capillary flow rate measurement system is: A capillary with a diameter of 0.5 mm and a tube length of 100 mm was placed horizontally between the linear array CCD and the parallel light source,and the left end of the capillary was immersed in the blood sample so that the blood sample was naturally flow under the action of a capillary,and using the difference of the output signal of the linear array CCD,the edge information of the blood sample was extracted,resulting in a series of blood samples of the discrete displacement,and coupled with the known linear array CCD scan cycle,we could get blood sample flow rate curve,and ultimately to achieve the purpose of measuring blood viscosity.Linear array CCD output is voltage signals,need to be converted into digital signals to facilitate further processing,we used the video signal dedicated analog signal converter to deal with the voltage signal,and then outputed gray value.In actual observation,it can be seen that the edge of the blood sample is not a specific pixel,but a region where the grayscale values are composed of multiple pixels,and need to be positioned to a specific edge.In this paper,an adaptive edge detection algorithm is proposed,which can extract the edge information in real time without storing all the data of one frame signal,and adapts to the small change of the gradient region,which has the characteristics of low consumption and strong real-time.We used FPGA(Field Programmable Logic Gate Array)as the core of the system,and FPGA was used to design the system drive,extract the image edge point and transmit data to PC side,This method speeded up the system development process,improved the overall performance.We used C ++ Builder to design PC-side software for blood sample flow curves and viscosity displays.Then,the flow curves of red ink,human whole blood and different hematocrit of blood were showed,and their flow characteristics were analyzed,the feasibility of the system was verified.Finally,the human body blood samples were subjected to 10 times the same conditions under the apparent viscosity measurement,measured low cut average of 6.940 mpa * s,high cut average of 2.298 mpa * s.The measured results are in good agreement with the normal reference value,and the measurement time is not more than 15 seconds.It can be seen that the system has the characteristics of simple system and short time consuming measurement,which has the possibility of family popularity.