移動式電阻抗斷層攝影術量測系統設計; Design of the Movable Electrical Impedance Tomography System

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Title:	移動式電阻抗斷層攝影術量測系統設計;Design of the Movable Electrical Impedance Tomography System
Authors:	施柏全;Po-Chan Shih
Contributors:	電機工程研究所
Keywords:	電阻抗斷層攝影術;移動式電阻抗斷層攝影術;人機介面;影像重建;有限元素法;牛頓拉夫遜法;鎖相;MEIT;GUI;image reconstruction;finite element method;Newton Raphson;lock in;electrical impedance tomography
Date:	2005-06-10
Issue Date:	2009-09-22 12:01:07 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	本篇論文之目的，在於設計移動式電阻抗斷層攝影術量測系統(MEIT)配合有限元素法以及修正式牛頓拉夫遜法，估算生物組織內部的阻抗分佈情形。MEIT系統設計包括資料擷取系統、馬達控制驅動電路、穩壓器、定電流源、解調器、電極選用、以及電極的配置等；軟體部分則是以Labview 圖控軟體設計人機介面(GUI)，GUI中包括自動量測介面、手動測試量測介面以及馬達驅動測試介面。 MEIT系統的特色是改善目前EIT系統在量測時因電極數目過多且無法在增加電極數目的狀況下，以移動電極的方式來提高電極的數目，並進一步提昇阻抗影像的品質。實驗的結果中得知，雖然由固定式量測所建立的6組個別影像可以估測出待測物體的位置，並且可觀察出待測物因電極轉動所產生不同像素值的變化，但是個別影像卻受到雜訊的影響使得影像的清晰度不高，因此本研究將6組個別影像重新做平均合成，或利用此6組數據再建立更高解析度之圖形，可得知經由合成後的影像清晰度會大幅提高，並同時消除雜訊在影像中的影響。雖然MEIT系統尚在研究發展的階段，然而重新合成後的影像可發現，影像中的清晰度已經明顯的提高且待測物位置也能清楚地指出，擴展電極數所合成之影像更可明確的看出影像位置。因此，驗證出利用移動式電極擴展量測資料到高品質的阻抗影像圖形是可行的。 In this paper, the principal purpose is to develop a novel imaging system, which is named Movable Electrical Impedance Tomography (MEIT). The MEIT system estimates the distribution of the internal conductance of the tissue by the finite element methods (FEM) and the modified Newton-Raphson. The Design of the MEIT system contains of the data collection system, the stepping motor circuit, the voltage control current source (VCCS), and the electrodes configuration. For part of the software, the Graphical User Interface (GUI) which is developed by Labview, consists of automatic measurement, manual measurement and motor test interfaces. In order to improve the resolution of image from the traditional EIT system which was limited by the number of electrodes, the MEIT system can obtain more amount of measuring data after moving the electrodes. Although the reconstruction results show that the six individual images constructed by the static electrodes could detect the position of the object approximately, some of the individual images were perturbed by the noise. So the MEIT system synthesizes the six individual images to a combined image and high-resolution image. These new images display clearly an imaging object and the eliminated noise simultaneously. Although the MEIT system is still under development, the combined images could indicate the position of object obviously. Therefore, the MEIT system provides a feasibility to reconstruct a high quality impedance image by moving electrodes.
Appears in Collections:	[Graduate Institute of Electrical Engineering] Electronic Thesis & Dissertation

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