Study On Cross-Range Scaling And Feature Extraciton In ISAR Image

Inverse synthetic aperture radar (ISAR) is a useful all-weather high-resolution radarsystem for moving target imaging and target recognition in a long-distance all-weathercondition. It is with great military and civil values. To meet the rising demand, theresearches about ISAR technologies are rapidly developing. Targets identificationtechnology based on ISAR image is an active topic in recent years。The target’smotion state is unknown due to the non-cooperative characteristics of the ISAR target.So the total rotation angle is unknown during the image time. As a result, thecross-range resolution of ISAR image is undeterminable. So the problem of cross-rangescaling is deeply studied in this paper. Then the problem of features extraction based onship ISAR image is also studied. Details are described as follows:Chapter1is the preface of this dissertation. It introduces the dissertation’s researchbackground at home and abroad, then briefly reviews the development of the ISAR. Finally, the main contents of this thesis are summarized.Chapter2introduces two kinds of high range resolution signals which are widelyused on wideband imaging radar. The Range-Doppler principle of ISAR and the ISARsignal processing technologies include motion compensation and imaging algorithm arealso introduced.Chapter3is the emphasis of this dissertation. It deeply studies the technology ofcross-range scaling, and introduces two kind of cross-rang scaling algorithm. One isbased on ISAR image, such as cross-rang scaling algorithm based on image rotationcorrelation. The other is based on parameter estimate, such as cross-rang scalingalgorithm based on estimating the chirp rate. The chapter gives the results of experimentand the performance analysis for all scaling algorithms.Chapter4mainly studies the feature extraction based on ship ISAR image. ISARimage is different from optical image. Speckle noise and stripe interfere should beremoved. Then the target region should be segmented from the image, and connectingand filling the target region are also needed. The chapter also gives the results of shipfeature extraction, include ship centerline extraction based simulation date and real data.Finally, the summary of the dissertation is made and the problems in furtherresearch are indicated.