Research On Oil Spill Detection Methods In SAR Images

The main work of the dissertation is one of the key aspects in SAR oceanic applications, namely, oil spill detection in SAR images. The dissertation focuses on three aspects, that is, SAR images despeckling, oil spill detection methods and the elementary probe of wavelet transform method's application in SAR oceanic field.In the research of despeckling in SAR images, the forming mechanism and statistic characteristic of noises are introduced first and then, the dissertation briefly introduces the main noise reduction algorithms, also the main noise suppression method classification. Based on the introduction, the four usually used despeckling algorithms are analyzed in detail and at the same time the despeckling effect estimation standard is brought forward. After analyzing the several methods in theory, the four algorithms are tested by using three real SAR oil spill images. The dissertation analyzes and values the different experiment effects at length and points out the suitable noise suppression algorithm in SAR oil spill images.In the research of oil spill detection methods in SAR images, firstly the dissertation introduces the detection mechanism of oil spill in SAR images and proves the possibility to detect oil slick. Secondly, the characters existing in SAR oil spill and oil slick detection are summarized and introduced. The importance is put on the four oil spill detection methods, both the theory analysis and detail realization. During the introduction of wavelet transform, the dissertation introduces it in theory at the beginning and then, combining with the subject content, discusses the oil spill detection method based on wavelet transform in SAR images in detail which including dyadic wavelet transform, edge-detection, multi-scale edge detection, edge thinning, edge connection and so on. It is very important for wavelet transform tochoose correct mother wavelet and the dissertation also discusses the question in detail. Based on the academic discussion, the four methods are compared by three real SAR oil spill images and the zero-antisymmetrical dyadic wavelet-based oil spill detection method in SAR images is advanced.In recent years, the applications of inspection and detection in SAR ocean field are developed increasingly. Wavelet transform is the widely used math tool in recent years that is used widely in image processing. Therefore, how to use wavelet transform in SAR oceanic field is worth to discuss. The dissertation elementarily discusses and probes other SAR oceanic application fields, mainly including ship detection, coastline detection and SAR image compression.