Sar Image Clutter Suppression And Recovery

Synthetic Aperture Radar (SAR) is a kind of high resolution imaging radar, High-resolution radar image can be obtained under day-and-night and all weather, so it is very vital significance in national defence modernization and national economy construction. Synthetic Aperture Radar has two kinds of imageing modes: Spotlight SAR and Strip Map SAR, the Spotlight SAR provides the opportunity to collect SAR data over a wide azimuth angular interval (independent of antenna azimuth beamwidth) with the potential for extremely fine azimuth resolution. this particular way of imaging can be achieved with higher azimuth resolution than Strip Map SAR, Therefore in military aspects and target identification,feature extraction,automatic target detection have the widespread application, however the Spotlight SAR coherence imaging, the antenna and the relative motion between the goal and radar as well as a long imaging time causes the SAR image to be disturbed by the clutter and noise ,So causes the image to be fuzzy and defocusing and so on . Therefore this dissertation mainly studies the Spotlight SAR image clutter suppression and restoration question.The main contributions of this dissertation are summarized as follows:First, A novel clutter suppression approach based on SAR image is proposed. This approach effectively improved the effect of clutter suppression and the target detection probability, while reduced the probability of false alarm.Second, The similarity of the Spotlight SAR and tomography imaging are revealed. A novel approach for spotlight SAR image restoration based on tomography model is presented for the characteristic of spotlight SAR image. The proposed algorithm performs more effectively than traditional Lee filter, Frost filter and Wiener filter restoration methods and the PSNR in terms of both blurring and speckle suppression and signal detail preservation(This dissertation obtain the PSNR is 7.626dB ),the approving restoration effect is obtained.Third, This dissertation is started from the basic concepts of synthetic aperture radar, As follow, the synthetic aperture radar and spotlight SAR imaging principle are introduced briefly, Moreover, the current radar of several major clutter suppression and the SAR image restoration methods are discussed, Meanwhile, subaperture decomposition and computer tomography are detailed.