Ship Target Imaging in Airborne SAR System Based on Automatic Image Segmentation and ISAR Technique

Abstract

The airborne synthetic aperture radar (SAR) image of ship target will be blurred for the complex motion of the target, which will influence the performance of feature extraction and target classification. In this paper, a refocusing method of ship target in airborne SAR image though the inverse synthetic aperture radar (ISAR) technique is presented. The novel contributions of this paper can be summarized as follows: (1) The residual phase of processed signal is analyzed in detail to illustrate the necessity of adopting ISAR technique; (2) A valid, labor-saving and automatic image segmentation approach via clustering algorithm is put forward for automatic data extraction and inverse mapping. The clustering algorithm we choose is the agglomerative hierarchical cluster algorithm (HCA), which doesn't require the number of categories in advance; (3) The refocused individual ISAR image of individual ship target is yielded though the range-instantaneous Doppler (RID) algorithm. Finally, the simulated and real measured data are processed, and imaging results verify the effectiveness of the novel algorithm presented in this paper.

An Efficient Preprocessing Approach for Airborne Hybrid SAR and ISAR Imaging of Ship Target Based on Kernel Distribution

“…Afterwards, the hybrid SAR and ISAR imaging algorithm in [13] is applied to generated the well-focused ship radar image. Here, the Chirp Scaling (CS) algorithm in [31] and [32] is chosen for the SAR processing, the range alignment method in [33] and the phase compensation method in [34] are used for the motion compensation, and the Range-Instantaneous Doppler (RID) algorithm based on the spectrum in [10] and [38] is used for the ISAR refocusing.…”

“…Due to the complex motion of ship target, the traditional SAR imaging algorithm will generate a defocused radar image. To produce a well-focused radar image, the hybrid SAR and ISAR technique is presented, which can process the motion of radar and target separately [4]- [10]. The idea of hybrid SAR and ISAR imaging was originally proposed and verified via simulated experiment by K. D. Ward [11]- [12].…”

“…(1) High computational complexity The hybrid SAR and ISAR imaging methods proposed in [10]- [19] suffer from the high computational complexity owing to processing the entire echo data. Some imaging time selection methods are proposed in [22]- [28], in which the Doppler frequency is segmented in time, and the stationarity is evaluated by the indexes such as image contrast [22], root mean square error [27] et al Hence, the selected time window will be affected by the segment length.…”

Recognition Method of Dim and Small Targets in SAR Images based on Machine Vision

“…Subsequently, the effectiveness of the algorithm was verified in the target recognition database. In reference [9], considering the decline in accuracy of ship target image due to the motion of the target, it proposed to combine clustering algorithm with SAR image recognition, and proposed HCA ship target aggregation algorithm in airborne SAR image. The distance algorithm is used as the basis for the generation of a single image.…”

SAR Signal Formation and Image Reconstruction of a Moving Sea Target

“…A SAR super-resolution multiple-signal classification (MUSIC) algorithm is discussed in [6]. A focusing method for SAR ship target imaging applying an ISAR approach is presented in [7]. Based on the sparsity of ship targets in a SAR image, an image-reconstruction method for multiple ship targets is proposed in [8].…”