Polarimetric SAR ship detection based on superpixel and sparse reconstruction saliency
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摘要: 極化SAR艦船檢測是極化SAR系統的重要應用之一,現有的極化SAR艦船檢測方法在具有強背景雜波的條件下容易將強雜波誤檢為目標,造成虛警;在多尺度艦船檢測情況下小尺寸的艦船容易淹沒在背景雜波中,造成小尺寸目標的漏檢。針對上述問題,本文提出一種基于超像素與稀疏重構顯著性的極化SAR艦船檢測方法。該方法首先用超像素分割方法將大幅的極化SAR場景圖像分割,在超像素級別上使用稀疏重構顯著性方法保留含有艦船目標的超像素,再在這些保留下來的超像素中逐像素使用稀疏重構顯著性檢測方法,得到最終的艦船檢測結果。本文選取強雜波場景和多尺度艦船檢測場景的兩個場景的ALOS-2衛星極化SAR數據進行對比實驗,實驗結果表明,本文方法在強雜波場景下品質因數達到94.87%,在多尺度艦船檢測場景下品質因數達到94.05%。Abstract: Polarimetric SAR ship detection is an important application of the polarimetric SAR system. Existing polarimetric SAR ship detection methods are plagued by erroneous detection of strong clutter and missed detection of small targets in multiscale situations. Particularly, the existing methods easily detect strong clutter as the target under strong background clutter, resulting in false alarms; in the case of multiscale ship detection, small ships are easily submerged in background clutter, resulting in missed detection of small targets. To solve these problems, this paper proposes a polarimetric SAR ship detection method based on superpixels and sparse reconstruction saliency. This method has two stages. In the first stage, the large polarimetric SAR ship detection scene image is segmented using the superpixel segmentation method to obtain a superpixel image. With the superpixel as the basic unit, a saliency detection method based on sparse reconstruction is used to obtain the saliency value of each superpixel in the image. Then, the superpixels that may contain ship targets are retained using the sea surface ship density defined in this paper. Accordingly, in the first stage, the superpixel regions that may contain ship targets are obtained through superpixel segmentation and sparse reconstruction saliency detection. Next, in the second stage, a saliency detection method based on sparse reconstruction is used to obtain the saliency value of each pixel in these reserved superpixel regions. Finally, the global threshold segmentation method is used for the pixels in these regions to obtain the final detection results of ship targets. In this paper, two polarimetric SAR images of the ALOS-2 satellite with different scenes were selected for an experiment. One image contains strong clutter on the sea surface; the other contains ships of different sizes and many small ships. The experimental results show that the proposed method can well determine the superpixel regions that may contain ship targets in the first stage and successfully obtain the ship detection results in the second stage. In addition, in both scenarios, the classic constant false alarm rate (CFAR) methods and a saliency detection method are used for comparison with the proposed method. The experimental results show that the proposed method produces almost no false alarms because it is insensitive to strong clutter; moreover, this method rarely misses small ship targets in the multiscale ship detection scene. The figure of merit of the proposed method reaches 94.87% in the strong clutter scene and 94.05% in the multiscale ship detection scene.
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Key words:
- polarimetric SAR /
- ship detection /
- sparse reconstruction /
- superpixel segmentation /
- saliency detection
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表 1 場景一極化SAR艦船定量檢測結果
Table 1. Polarization SAR ship quantitative detection results of scene 1
Method Nc NFA NM FoM/% CA-CFAR 37 3 2 88.10 OS-CFAR 36 5 3 81.82 Saliency method 35 0 4 89.74 Our method 37 0 2 94.87 表 2 場景二極化SAR艦船定量檢測結果
Table 2. Polarization SAR ship quantitative detection results of scene 2
Method Nc NFA NM FoM/% CA-CFAR 75 0 7 91.46 OS-CFAR 77 6 5 87.50 Saliency method 65 0 17 79.27 Our method 79 2 3 94.05 www.77susu.com -
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