The Study Of Mi System Basing On Confocal Algorithm

Stroke has severe harm, which causes brain damage, complications and death with improper treatment. The deaths caused by stroke have increased yearly. The current treatment is most effective in short-term of the incidence, it will cause lots of brain cells death in long-term. However, treatment for the long-term cases might cause serious consequences. Therefore, rapid and timely diagnosis plays a key role in decision-making and treatment programs, particularly in the first appeared few hours of the symptoms.Currently the stroke detection depend on the advanced but large instruments and equipment, such as CT scans, magnetic resonance imaging(MRI) and so on, but it must be carried out to the hospital and it can't be used as a regular stroke detection methods. Microwave imaging is an imaging means which refers to the information carrier, microwave irradiate to the object, and then reconstructing the shape of the object or the(complex) permittivity distribution scattered by external field measurements. Since the size of the dielectric constant is closely related to water content of biological tissue, it is very suitable for microwave imaging of biological tissue imaging, when large discontinuities limit the efficiency of ultrasound imaging, biological tissue density limits the use of X-rays, but microwave can play a unique role, it is not available to obtain information for other imaging means. Microwave imaging is safe, low cost and temperature imaging theoretically.The paper focus on microwave imaging system for stroke detection which based on confocal algorithm, the imaging system utilizes slotted ultra-wideband antenna as receiving and sending, using vector network analyzer(VNA) as the source, so that the ultra-wideband antenna signal is applied to the object. Because brain structure is relatively complex, the head model used in the experiments is a simplified model, the model is placed in the rotating table. The acquisition of measured data on the objects is in 16 and 32 antenna position. Since VNA is only sweeping, no pulse source, it is necessary to use stepped-frequency continuous wave(SFCW) sampling technique to collect effectively. The superior machine control VNA and rotating table and the acquisition is automation. The collected signal S11 or S21 will upload to the terminal, the subsequent process the confocal imaging algorithm, the algorithm is based on delay-sum approach. The paper improve the confocal algorithm and use it in MI successfully, then using fuzzy integrated judging method to analyze. The experimental results accurately detect the presence and location of foreign body relationship, which proves the feasibility of using ultra-wideband microwave signals to detect foreign body.