Similarity ratio based algorithms to generate SAR superpixels

Akyılmaz, Emre
Synthetic Aperture Radar (SAR) has the capability of working in all weather conditions during day and night that makes it attractive to be used for automatic target detection and recognition purposes. However, it has the problem of high amount of multiplicative speckle noise. Superpixel segmentation as a preprocessing step is an oversegmentation technique that groups similar neighboring pixels into regularly organized segments with approximately the same size. As boundaries of the objects are important elements to be traced, superpixels should adhere well to the edges. This can only be achieved by an algorithm robust to speckle noise. In this thesis, similarity ratio is first developed as a new metric that is robust to speckle noise. Secondly, Mahalanobis distance is used instead of Euclidian so that the superpixel can fit better to shapes in the real world. Thirdly, the constant determining the relative importance of radiometric and geometric terms is replaced with an adaptive function. The performance of combinations of similarity ratio with Euclidean distance (SREP), Mahalanobis distance (SRMP) and Mahalanobis distance with adaptive scheme (SRAMP) are evaluated by conducting experiments on real and synthetic images. The experimental results showed that similarity ratio and adaptive Mahalanobis proximity (SRAMP) outperforms the other approaches in terms of uniformity, compactness and visual appearance.


Analysis of near-field ultra-wideband radar imaging algorithms
Arabacı, Ahmet; Koç, Seyit Sencer; Department of Electrical and Electronics Engineering (2017)
Recently, near-field ultra-wideband radar imaging algorithms have an important place in short range imaging applications by providing high resolution in both range and cross-range. In this study, the near-field ultra-wideband radar imaging algorithms in the literature such as Holographic Image Reconstruction Algorithm, Range Migration Algorithm, MIMO Based Range Migration Algorithm and MIMO Based Kirchhoff Migration Algorithm have been implemented using MATLAB. The algorithms are applied to modeled transmit...
Global appearance based airplane detection from satellite imagery
Arslan, Duygu; Alatan, Abdullah Aydın; Department of Electrical and Electronics Engineering (2012)
There is a rising interest in geospatial object detection due to not only the complexity of manual processing of such huge amount of data provided by high resolution satellite imagery but also for military application needs. A fundamental and yet state-of-the art approach for object detection is based on methods that utilize the global appearance. In such a holistic approach, the information of the object class is aimed to be modeled as a whole in the learning phase. And during the classification, a decisio...
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Bayram, Eda; Alatan, Abdullah Aydın; Vural, Elif; Department of Electrical and Electronics Engineering (2017)
Airborne Laser Scanning is a well-known remote sensing technology, which provides quite dense and highly accurate, yet unorganized, point cloud descriptions of the earth surface. However, processing of such a 3D point cloud is quite challenging due to its irregular structure and 3D geometry. In this thesis,two novel approaches for the analysis of unorganized 3D point cloud data are proposed, specifically the ones that are generated by the airborne mounted LIDAR sensor. These methods rely on the spectral grap...
Camera electronics and image enhancement software for infrared detector arrays
Küçükkömürler, Alper; Akın, Tayfun; Department of Environmental Engineering (2012)
This thesis aims to design and develop camera electronics and image enhancement software for infrared detector arrays. It first discusses the camera electronics suitable for infrared detector arrays, then it concentrates on image enhancement software that are implemented including defective pixel correction, contrast enhancement, noise reduction and pseudo coloring. After that, testing and results of the implemented algorithms were presented. Camera electronics and circuit operation frequency are selected c...
Through-The-Wall Target Detection using GPR A-Scan Data: Effects of Different Wall Structures on Detection Performance
DOĞAN, MESUT; Sayan, Gönül (2017-09-27)
Ground penetrating radar (GPR) is an electromagnetic sensor based on the ultra-wideband radar technology that can also be used for through-the-wall (TTW) target recognition. Search for the presence of designated targets hidden behind the walls, such as stationary or moving human bodies or certain types of weapons, is addressed in various critical applications; in rescue missions after earthquakes or in military operations, etc. In such inverse problems, type of the wall is as important as the properties and...
Citation Formats
E. Akyılmaz, “Similarity ratio based algorithms to generate SAR superpixels,” Ph.D. - Doctoral Program, Middle East Technical University, 2017.