A Study Of Algorithm For Microwave Imaging

Microwave imaging has always aroused worldwide attention and plays an essential role in military applications. Firstly, my research is focused on range profile. Characters of range profile are analyzed. Under single polarized measurement, wavelet transform is used to filter noise, recognition results of target are evidently raised. Against the conventional definition, a new time-frequency range profile is present, thereby the more accurate features of target can be picked up and identified.Secondly, methods of conductor imaging are studied. The fundament of two-dimension imaging for rotating target is discussed. Three imaging methods are introduced: Range-Doppler imaging, Projection tomography imaging, Polar-Doppler imaging. Several interpolation methods are introduced, and their simulation results are compared, and cubic spline interpolation is proved to be the best.Next, time-frequency imaging is utilized to study the conductor objects. Short-time Fourier transform and time-frequency distribution series are applied to time-frequency imaging. Time-frequency distribution series based on wavelet transform is discussed., and a new time-frequency tool: frequency-shear distribution is introduced into radar imaging fields. A new double time-frequency imaging method is present to improve the imaging quality. Analyzing the SNR of time-frequency imaging method, it is found that the time-frequency method can greatly improve the SNR of image. The mentioned methods are applied to a F-16 plane model, and the results are agreeable.Finally, near-field microwave imaging methods are studied. Combining near-field measurement and target geometrical shape, a new near-field microwave imaging approach by plane-wave spectrum is produced. Synthetic plane-wave technique and near-field imaging is studied, simulation results of this approach are given.