SAR图像舰船目标长宽特征提取技术

摘要

In this paper, a length and width feature extraction method for the ship target in the SAR images is proposed. Firstly, the SAR image is segmented by the level sets. The domain elimination method is adopted for the segmented images to remove clutter in the next step. Consequently, the slice image of target is obtained. Then, the minimum bounding rectangle and ellipse fitting methods are used for the feature extraction. We use the minimum bounding rectangle to obtain the long axis and the rotational angle of the ship in SAR image, and apply the Ellipse fitting method to get short axis of the ship target. Thus, the feature information of the ships including length, width and angle is obtained. Experimental results illustrate that the proposed method can extract the length and width feature of a ship target in SAR image effectively and accurately. Meanwhile, it can weaken the influence of speckle noise and background clutter in SAR image.%SAR图像特征提取是目标识别中的关键步骤，直接影响目标识别的结果。长度类特征因其简单直观、效率高、易于提取等优势，常被作为船只类型的初始判定，针对 SAR图像舰船目标长宽特征提取问题，本文提出一种新的方法。首先通过水平集分割获得目标轮廓，其次采用区域消除方法滤除杂波，获得预处理后的目标图像；其次通过最小外接矩形拟合目标，获取舰船目标切片的长轴、旋转的角度；再次采用最小二乘法椭圆拟合获取舰船目标短轴；最后得到舰船目标的长宽特征。通过实测SAR图像处理结果表明，本文方法能够在背景杂波干扰下，抑制相干斑噪声的影响，提高了长宽提取的精度，是一种有效的舰船目标长宽特征提取方法。