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一、引言多年来,在医学领域用电离辐射得到人体的影象已成为诊断过程的一部分.最近,其它用于探测的辐射,特别如超声,已给出了成功的诊断图像.随着电离辐射(X线、同位素)核磁共振成像中使用断层摄影法,断层摄影法已广泛地应用于临床上.在过去的几年里,还应用其它的探测辐射来得到断层图像,包括超声、阻抗断层成像中的极低频电磁场和微波.实际的微波成像由照射体和测量场组成.用低功率相干微波作照射器,照射需成像的人体,然后在相对一侧测量由人体散射的场(反射成象).测得的数据可以用特殊的重建算法处理,给出散射体上的复介电常数的信息.微波成像中,测量到的电磁场是复数的,重建也是复数的.这样可以利用更多的信息,不同的参数都可以用图像形式来表示.微波成像具有
I. INTRODUCTION Over the years, imaging of the human body with ionizing radiation in the field of medicine has become part of the diagnostic process. Recently, other diagnostic radiations, especially ultrasound, have been given successful diagnostic images. As ionization Radiography (X-ray, isotope) tomography has been used in tomography, tomography has been widely used in clinical .In the past few years, also used other detection radiation to obtain tomographic images, including ultrasound, impedance tomography Imaging of very low frequency electromagnetic fields and microwaves. The actual microwave imaging consists of a radiator and a measurement field. The low-power coherent microwave is used as an illuminator to illuminate the human body to be imaged and measure the field scattered by the human body on the opposite side The measured data can be processed using a special reconstruction algorithm that gives information on the complex permittivity of the scatterer. In microwave imaging, the measured electromagnetic fields are complex and the reconstruction is also complex, so that more can be used Of the information, different parameters can be expressed in the form of images