ارزﯾﺎﺑﯽ ﻋﻤﻠﮑﺮد ﺳﺎﻣﺎﻧﻪ ﺗﻮﻣﻮﮔﺮاﻓﯽ اﻣﭙﺪاﻧﺲ اﻟﮑﺘﺮﯾﮑﯽ ﺗﺤﺖ اﺳﺘﺮاﺗﮋي ﺳﻨﺠﺶ اﺑﺘﮑﺎري ﺑﺮاي ﭘﺎﯾﺶ ﺳﯿﺎل دوﻓﺎزي ﺟﺎﻣﺪ-ﻣﺎﯾﻊ

Evaluation of Electrical Impedance Tomography System in an Innovative Sensing Strategy for Two-phase Solid-liquid Fluid Monitoring

ﺗﻮﻣﻮﮔﺮاﻓﯽ اﻣﭙﺪاﻧﺲ اﻟﮑﺘﺮﯾﮑﯽ )EIT(، ﺗﮑﻨﯿﮏ ﺗﺼﻮﯾﺮﺳﺎزي ﻏﯿﺮﻧﻔﻮذي اﺳﺖ ﮐﻪ ﺗﻮﺳﻂ ﺗﺰرﯾﻖ ﺟﺮﯾﺎن اﻟﮑﺘﺮﯾﮑﯽ ﺑﻪ ﻣﺠﻤﻮﻋﻪاي از اﻟﮑﺘﺮودﻫﺎ و ﻗﺮاﺋﺖ وﻟﺘﺎژ از اﻟﮑﺘﺮودﻫﺎ، ﺧﻮاص ﺳﯿﺎل ﭼﻨﺪﻓﺎزي ﻣﺎﻧﻨﺪ ﺗﻮزﯾﻊ ذرات و ﻏﻠﻈﺖ ﺣﺠﻤﯽ را اﻧﺪازهﮔﯿﺮي ﻣﯽﮐﻨﺪ. اﺳﺘﺮاﺗﮋي ﺗﺰرﯾﻖ و ﻗﺮاﺋﺖ ﺳﯿﮕﻨﺎل از اﻟﮑﺘﺮودﻫﺎ در ﮐﯿﻔﯿﺖ ﺑﺎزﺳﺎزي ﺗﺼﻮﯾﺮ و دﻗﺖ اﻧﺪازهﮔﯿﺮي ﺗﺎﺛﯿﺮﮔﺬار اﺳﺖ. در ﻣﺤﯿﻂﻫﺎي ﺑﺰرگ و ﺑﺎ رﺳﺎﻧﺎﯾﯽ ﺑﺎﻻ اﺳﺘﺮاﺗﮋي-ﻫﺎي ﻣﺮﺳﻮم ﭼﻮن ﻣﺠﺎورﺗﯽ ﻗﺎدر ﺑﻪ ﻗﺮاﺋﺖ ﺳﯿﮕﻨﺎل ﺑﺎ ﮐﯿﻔﯿﺖ ﻧﯿﺴﺘﻨﺪ. ﺑﻨﺎﺑﺮاﯾﻦ ﻫﺪف از اﯾﻦ ﭘﮋوﻫﺶ ﺳﺎﺧﺖ و ارزﯾﺎﺑﯽ ﺳﺎﻣﺎﻧﻪ EIT ﺗﺤﺖ اﺳﺘﺮاﺗﮋي اﺑﺘﮑﺎري ﺑﺮاي ﺗﻌﯿﯿﻦ آﻧﻼﯾﻦ ﺗﻮزﯾﻊ ذرات و ﻏﻠﻈﺖ ﻣﻮاد دو ﻓﺎزي ﺟﺎﻣﺪ- ﻣﺎﯾﻊ در ﻣﺤﯿﻂﻫﺎي ﻧﺴﺒﺘﺎ ﺑﺰرگ اﺳﺖ. ﺑﺪﯾﻦ ﻣﻨﻈﻮر، 16 اﻟﮑﺘﺮود ﺑﺮ روي ﻣﺨﺰن ﺣﺎوي ﻣﻮاد ﻧﺼﺐ ﺷﺪﻧﺪ. ﻓﺎز ﻣﺎﯾﻊ آب ﺑﺎ رﺳﺎﻧﺎﯾﯽ ﻣﻌﻠﻮم و ﻓﺎز ﺟﺎﻣﺪ ﺑﻄﺮي در اﻧﺪازهﻫﺎي ﻣﺨﺘﻠﻒ ﺑﻮد و در ﺳﻪ ﻣﻮﻗﻌﯿﺖ ﻣﺨﺘﻠﻒ ﻋﻤﻠﮑﺮد ﺳﺎﻣﺎﻧﻪ ﻣﻮرد ارزﯾﺎﺑﯽ ﻗﺮار ﮔﺮﻓﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ اﺳﺘﺮاﺗﮋي اﺑﺘﮑﺎري، ﻗﺎﺑﻠﯿﺖ ﺗﺸﺨﯿﺺ و ﺗﻤﺎﯾﺰ ﺷﯽء ﻫﺪف را در اﺑﻌﺎد ﻣﺨﺘﻠﻒ و ﻣﻮﻗﻌﯿﺖﻫﺎي ﻣﺨﺘﻠﻒ دارد. ﻧﺮخ ﺳﯿﮕﻨﺎل ﺑﻪ ﻧﻮﯾﺰ 1/05 دﺳﯽﺑﻞ و داﻣﻨﻪ دﯾﻨﺎﻣﯿﮏ ﭘﺘﺎﻧﺴﯿﻞﻫﺎي ﻣﺮزي 1600 ﻣﯿﻠﯽوﻟﺖ ﺑﻮد. ﺣﺴﺎﺳﯿﺖ ﺑﻪ ﮐﻨﺎرهﻫﺎ و ﻧﺰدﯾﮏ اﻟﮑﺘﺮودﻫﺎ ﺑﯿﺸﺘﺮ از ﺣﺴﺎﺳﯿﺖ ﺑﻪ ﻣﯿﺎﻧﻪ ﺑﻮد. ارزﯾﺎﺑﯽ ﭘﺎراﻣﺘﺮﻫﺎي ﮐﯿﻔﯿﺖ ﺗﺼﻮﯾﺮ، ﻧﺸﺎن داد ﮐﻪ در ﺷﯽء ﻫﺪف ﺑﺎ اﻧﺪازه ﻣﺘﻮﺳﻂ و ﺑﺰرگ، در ﻣﻮﻗﻌﯿﺖﻫﺎي ﻧﺰدﯾﮏ ﺑﻪ اﻟﮑﺘﺮودﻫﺎ، ﺧﻄﺎ در اﻧﺪازه ﮐﺎﻫﺶ ﻣﯽﯾﺎﺑﺪ و در ﻫﺮ ﺳﻪ اﻧﺪازه ﺷﯽء ﻫﺪف، اﯾﺠﺎد ﺣﻠﻘﻪ ﺑﻪ ﻣﯿﺰاﻧﯽ ﻧﺒﻮد ﮐﻪ ﻣﻨﺠﺮ ﺑﻪ ﻋﺪم ﮐﯿﻔﯿﺖ در ﺗﺼﻮﯾﺮ ﺑﺎزﺳﺎزي ﺷﺪه ﺷﻮد. ﺑﻨﺎﺑﺮاﯾﻦ ﻣﯽﺗﻮان ﻧﺘﯿﺠﻪ ﮔﺮﻓﺖ ﮐﻪ اﺳﺘﺮاﺗﮋي اﺑﺘﮑﺎري اراﺋﻪ ﺷﺪه، ﻋﻤﻠﮑﺮد ﻣﻄﻠﻮﺑﯽ ﺑﺮاي ﺗﻌﯿﯿﻦ ﺗﻮزﯾﻊ ﻣﻮاد در ﻣﺤﯿﻂﻫﺎي ﺑﺰرگ را دارد.

Electrical impedance tomography (EIT) is a non-invasive imaging technique that measures properties of multiphase fluids such as particles distribution and volume concentration by injecting a current into a set of electrodes and reading voltages from the electrodes. A strategy of injection and signal measurement has an important role in the image reconstruction quality and measurement accuracy. In large phantoms with high-conductivity, conventional strategies such as adjacent are not able to measure the signal with suitable quality. Therefore, the purpose of this study is to construct and evaluate the EIT system under an innovative strategy for online determination of particles distribution and concentration of solid-liquid fluid in large phantoms. The sensors of this instrument consist of 16 circular electrodes. The liquid phase was water with known conductivity and solid phase was the bottle in different sizes and in three different situations. The results showed that the innovative strategy has the ability to recognize and differentiate the target in different dimensions and different positions. The signal-to-noise rate was 1.05 dB and the dynamic range of boundary potentials was 1600 mV. The sensitivity to the sides and near the electrodes was more than the sensitivity to the middle. In positions close to the electrodes, size error decreases in medium and large target. In the three sizes of the target, ringing has no negative effect on the reconstructed image quality. Therefore, it can be concluded that the innovative strategy has a desirable performance for determining the distribution of materials in the large phantom.