提出一种基于长度归一化扫描的合成孔径雷达(SAR)图像船舶尾迹检测算法。存在距离向运动分量的船舶在SAR图像上会发生方位向偏移,那么尾迹的起点必在方位向上这一偏移量范围内。根据这一物理事实,将尾迹检测的搜索范围限定在可能为尾迹的线段上,从而提高了检测效率。算法通过利用线性积分和长度归一化这两个方法将矩形滑动窗口下的线性特征检测转化为了点特征检测,并通过经典的虚警率(CFAR)检测理论实现检测结果的输出。利用COSMO-SkyMed数据对该算法进行了实验验证,实验结果表明,该算法在尾迹检测上具有检测能力强、速度快的优点,船舶速度反演具有较高精度。

This paper presents a new ship-wake detection algorithm in synthetic aperture radar (SAR) images based on the length normalized scan method. The range component of a ship's movement leads to azimuth shift in SAR images. Therefore, the start point of wake must be located in the azimuth direction. According to this physical facts, length normalized scan is performed on-line on image parts which may be wakes. By means of linear integral and length normalization technology, linear feature detection is transformed to point detection. Then the probability model in the scan domain is constructed to realize constant false alarm rate (CFAR) detection. COSMO-SkyMed data is used to validate this method. The experimental results show that this algorithm is effective for ship wake detection and can extract ship's velocity with high accuracy.