Study Of Human Body Composition Analysis Method Based On Bio-Impedance Spectroscopy Measurement

Body composition(BC)denotes a series of macroparameters such as total body water content,extracellular fluid,intracellular fluid,free fat mass and fat mass,and so on,which reflects the physiological and pathological information like fluid balance,nutritional status and growth development,and has become an important auxiliary means in the early diagnosis and monitoring process of human disease treatments.Bioelectrical impedance analysis(BIA)is a measuring method for body composition analysis based on the changes of biological impedance.Compared with the traditional BC measurement methods(such as crease method,underwater weighing method,dual energy X-ray absorption method,etc.),BIA is rapid,simple,and noninvasive,and has become the most popular BC analysis method in recent years.This thesis aims to develop a low cost bioimpedance spectroscopy(BIS)measuring instrument,construct a BC analysis method based on BIS measurement,and establish a BC model equation which will be specifically suitable for the body characteristics of Chinese people.This thesis mainly includes three parts::1.The design of BIS measurement system based on m-sequence.In order to overcome the shortcomings of the little impedance information under single frequency and the low speed under sweeping frequency of the current BC analyzer,this thesis chose the m-sequence(the multi-frequency synchronization pseudo random signal)as an excitation signal and designed a fast BIS measurement system.The result showed that the high precision has been realized by the system,in which the amplitude relative error is less than 0.5%and the phase absolute error is less than 3.5°2.The data collection of the 80 volunteers.The BIS and BC values of 80 volunteers have been fulfilled by using the designed instrument and the standard BC analyzer SFB7.Every volunteer's parameters like body height,weight,gender,etc also have been collected,considering its effects on BC.3.Establishment of the BC calculation equation which can be suitable for the Chinese peopleThe total body water(TBW)and free fat mass(FFM)calculation equation were predicted by the method of linear regression.In addiction,the nonlinear relationship between human extracellular fluid(ECW)and Ri was established.Compared with the SFB7,the TBW relative error was within 4.5%,the FFM relative error is within 3%,the ECW relative error is less than 4%and the ICW relative error is less than 3%.