Atefi S R, Buendia R, Lindecrantz K, Seoane F
School of Technology and Health, KTH Royal Institute of Technology, Stockholm, Sweden.
Annu Int Conf IEEE Eng Med Biol Soc. 2012;2012:3368-71. doi: 10.1109/EMBC.2012.6346687.
One of the most common measurement artifacts present in Electrical Bioimpedance Spectroscopy measurements (EBIS) comes from the capacitive leakage effect resulting from parasitic stray capacitances. This artifact produces a deviation in the measured impedance spectrum that is most noticeable at higher frequencies. The artifact taints the spectroscopy measurement increasing the difficulty of producing reliable EBIS measurements at high frequencies. In this work, an approach for removing such capacitive influence from the spectral measurement is presented making use of a novel method to estimate the value of the parasitic capacitance equivalent that causes the measurement artifact. The proposed method has been tested and validated theoretically and experimentally and it gives a more accurate estimation of the value of the parasitic capacitance than the previous methods. Once a reliable value of parasitic capacitance has been estimated the capacitive influence can be easily compensated in the EBIS measured data. Thus enabling analysis of EBIS data at higher frequencies, i.e. in the range of 300-500 kHz like measurements intended for cerebral monitoring, where the characteristic frequency is remarkably higher than EBIS measurements i.e. within the range 30 to 50 kHz, intended for body composition assessment.
生物电阻抗谱测量（EBIS）中最常见的测量伪像之一来自寄生杂散电容产生的电容性泄漏效应。这种伪像会在测量的阻抗谱中产生偏差，在较高频率下最为明显。该伪像会影响光谱测量，增加在高频下进行可靠EBIS测量的难度。在这项工作中，提出了一种从光谱测量中去除这种电容性影响的方法，该方法利用一种新颖的方法来估计导致测量伪像的等效寄生电容值。所提出的方法已经在理论和实验上进行了测试和验证，并且与以前的方法相比，它能更准确地估计寄生电容值。一旦估计出可靠的寄生电容值，就可以很容易地在EBIS测量数据中补偿电容性影响。从而能够在更高频率下分析EBIS数据，即在300 - 500 kHz范围内，如用于脑部监测的测量，其特征频率明显高于用于身体成分评估的EBIS测量频率，即在30至50 kHz范围内。
