LAUSR

A weighted parameter vector lbgχl/bglsubgnorml/subg based on extracellular fluid resistance in Cole impedance model is hereby proposed in order to compensate for the volatile-distributed current. The volatile-distributed current due to variance in the unknown contact impedance in electrical impedance tomography (EIT) sensor distorts the ideality of the frequency-dependent behavior of the object of interest which leads to inaccuracy in the reconstructed images. The source of the variance in the unknown contact impedance include the use of electrodes of inconsistent impedance values, the electrochemical reaction or due to improper attachment of electrodes to the object of interest. The lbgχl/bglsubgnorml/subg represents the current pathway lengths at zero frequency measurement which reflects the volatile-distributed current and is used to determine the source of the measured impedance. The source can the background object as the normal physiological condition, inclusion object as the abnormal physiological condition, or from systematic error as the unknown contact impedance which varies. The new reconstruction methods are derived from the frequency-difference EIT (fd-EIT) and the weighted-frequency-difference EIT (wfd-EIT) using lbgχl/bglsubgnorml/subg. The new reconstruction methods are frequency-difference electrical impedance spectro-tomography (fd-EIST) and weighted-frequency-difference electrical impedance spectro-tomography (wfd-EIST). The performance of the fd-EIST and wfd-EIST were evaluated by experimental and simulation studies using bio-materials with frequency measurements from ligfl/ig = 500 Hz to 100 kHz and the results compared to those form fd-EIT and wfd-EIT. Results showed that using lbgχl/bglsubgnorml/subg reduces the root mean square error (RMSE), position error (PE), ringing (RNG), and shape deformation (SD). It also increases the ideality of the frequency-dependent behavior either for the inclusions or the background objects in different frequencies.