| The advance of material technology, sensor technology and the MEMS in particular opens the door for the micro-diagnosis and treatment in human gastrointestinal tract (GI tract). Over the last decade, extensive GI tract examination methods have emerged, i.e., capsule endoscopy, site specific drug delivery system, sampling capsule, physiological parameters monitoring devices and just to name a few. The precise localization of microcapsule contributes to the determination of observation point of endoscope, of releasing position of therapeutic agents and of sampling point of GI fluids.Currently, means of ultrasound, medical imaging, radio-frequency detection, and magnetic marker have been employed to…. Because of the advantages of real-time, noninvasive tracking and simplicity, this work is aimed to design software for a magnetic localization system which is based on magnetic sensor array. The software measures the magnetic field of magnet inside the micro diagnosis and treatment device by controlling the magnetic sensor array outside the human body, and then works out the position and attitude information of magnet by using the achieved theory algorithm. Finally the software shows the result by using 2D and 3D view.The software implementation of magnetic localization system for micro diagnosis and treatment devices is investigated in this paper. The paper first analyzes the computer interface and control circuit of the magnetic field detection hardware platform, realizes the function partition of data acquisition by using object-oriented method and unified modeling language, and then designs a data acquisition class based on magnetic sensor array which has the following functions: control of the interface circuit and controlling circuit, master-slave control of serial data transmission, data format output etc. The experiment demonstrates that the data acquisition realized by the class controls the hardware platform well and acquires the acquisition data steadily and reliably.Data processing includes acquisition data preprocessing and localization algorithm based on nonlinear least square method. Data preprocessing includes reducing the measurement error caused by sensor sensitivity differences, sensor position offset, and sensor orthogonal error. To increase the accuracy of the localization algorithm input data, a pre-processing is assigned to reduce the errors caused by hardware and the data acquisition process. Localization algorithm based on nonlinear least square method has been achieved by using LM algorithm which version is 2.1.3. According to the objective function, the algorithm finds the optimal solution by using iterative method. The algorithm programmed by C language has been compiled to the C++ language, so the algorithm codes can produce high executing efficiency. The experiment indicates that in the measuring range the location coordinates can describe the position of capsule with high accuracy.The location information of electronic capsule has been displayed in 3D perspective by using VTK's volume rendering programming. Through the three-dimensional modeling, the author simulates the human body and the trajectory of the capsule by using simple three-dimensional models. Users can scale, pan and rotate the 3d view, and observe the relative position in human body from different perspectives. In order to improve the efficiency of data processing and realize multitask-parallel, such as the data acquisition, data processing, computer drafting and data storage, windows multi-thread programming has been used in the software. Cyclic buffering queues, single linked list have been designed as variables in critical section. Inter-thread communication has been realized by using mutex that can ensure synchronous running of all threads in process. In order to construct a simple and friendly software interface, software framework has been designed by MFC programming in this paper. The windows framework has been divided into several functional areas by using static framework splitting, which can ensure the text and graphics reasonable layout. The author designs an extension toolbar class based on MFC that can show all functions intelligently and vividly to users.The localization software proposed in this paper addressed the key problem such as three dimensional localization, tracking and reference coordinate system adjustment. The operator can collect the position of the micro diagnosis and treatment device from the main interface of the localization software. This localization software has the following advantages: operation stability, interface-friendliness, fine real-time performance and simplicity of operation. |
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