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In order to extract the impedance information at different frequencies in our multi-frequency electrical impedance tomography (EIT) system, a digital demodulation method was employed. Theoretically, this method can improve the SNR by √(N/2) times, if we sampling N point per period. Moreover, as very little system resources been needed in this method, all the calculating operations can be finished...
This paper designs one mobile physiological information monitor system based on the ZigBee protocol. The hardware structure is presented. The network communication characteristic of this system was analyzed. The paper points out the disadvantage of the connection method in the ZigBee protocol. One improved connection method is proposed. Through carries on the comparison and the simulation to the routing...
This paper designs one physiological information monitor system based on the ZigBee wireless communication protocol. The hardware structure is presented. The network communication characteristic of this system was analyzed. The paper points out the disadvantage of the connection method in the ZigBee protocol. One improved connection method is proposed. Through carries on the comparison and the simulation...
A movement during measurements can generate motion artifacts in photoplethysmography(PPG) signals. The motion artifacts reflect some information of tester's motion. If we can extract the relevant information from these interferences, it probable will be a new information collection method for portable physiological monitor. This paper first analyzes the relationship between the motion artifact and...
The structural similarity of the head model affects the accuracy of solutions to electrical impedance tomography (EIT) forward problem. The conductivity of skull is one of the most sensitive head model parameters. Generally, the skull is considered as a homogeneous whole, while in fact it is inhomogeneous. In this paper EIT images are reconstructed with different head models to detect and localize...
As a convenient, un-injurious and low cost method for women breast tumor diagnosis, Electrical Impedance Scanning (EIS) is being paid increasing attention. But EIS still has some problems. In theory the malignant tumor has higher electrical conductivity than normal tissue and benign tumor, so the cancer will be recognized in the EIS image as a bright spot. However, in practical the difference is not...
An electrical impedance scanning (EIS) system was studied to meet the requirement of clinical breast screening. A quick examination, easy operation, safe electrical isolation and obvious diagnosis results are four main factors to a screening system. Basing on these considerations, a multi-frequency signal sampling system controlled by ARM chip was setup and the measuring data were transmitted to PC...
A new post-processing algorithm was developed for EIS image in order to improve the accuracy of diagnosis. This algorithm automatically analyzes data and recognizes the light region in the EIS image basing on the data process criterions. The threshold criterion and the modality criterion were derived from the ideal saline-tank phantom experiment. And the filter criterion came from the analysis of...
We constructed an impedance spectroscopy measurement system based on frequency response analyzer. Using four-terminal method, we measured impedance spectroscopy of rabbit different tissues in vitro within 5 to 360 minutes after excision at the frequency range from 1Hz to 1MHz. According to the measurement results, we analyzed the changes of characteristic parameters (Ro, Rinfin, fc and alpha) of different...
A 16-channel magnetic induction imaging system is introduced briefly. Highly precise phase and magnitude detecting method is applied to the information acquisition. The resolution of phase detecting is 0.003deg. The results of magnitude detecting also provide us with useful information. The characteristic curves are smoother than that of our previous system. One dimension results in different positions...
An image monitoring system using electrical impedance tomography (EIT) for intraperitoneal bleeding was designed (FMMU V3.5). It consists of a constant current driving source with frequency of 50 KHz, a high accuracy measurement module, a driving and measuring mode program-controlled circuits, a data acquisition card, an optoelectronic isolated digital I/O board, and a custom-specified linear power...
To seek a single source drive pattern that is more suitable for brain electrical impedance tomography (EIT), a comparison between adjacent, cross, polar and newly proposed quasi-polar drive patterns was made in aspects of boundary voltages dynamic range, independent measurement number, total boundary voltage changes and anti-noise performance based on an equivalent circuit of the brain resistivity...
It is found that electrical impedance tomography(EIT) is promising in its application to the clinical image monitoring and that the back-projection algorithm of EIT can meet the preliminary requirements of the real-time monitoring through our work. In order to improve the computed speed and the imaged resolution, different ways of completing the algorithm were tried in this paper. Moreover, it is...
Electrical impedance scanning (EIS) is a new adjunctive diagnostic method for women breast cancer examination. In clinic research, we found some influencing factors which can induce a bad EIS imaging results. In order to analyze the influencing factors on EIS imaging and find the solutions, we set up an EIS workbench which can simulate the influencing factors that may happen in a clinic. We studied...
To establish a high precision data acquisition system for multi-frequency electrical impedance tomography (EIT), a series of methods were introduced. Those methods include building a driving signal with up to four frequency components to diminish the effect of the dynamic change of tissues resistivity, extracting the impedance information by a digital demodulator that can improve the SNR by 8 times...
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