基于单景高分四号卫星多光谱影像的舰船运动特征检测

高分辨率地球同步轨道（GEO）遥感卫星技术能够在短时间内对大范围海域进行高频重复监测，有望近实时地获取海上舰船运动特征。以广东省珠江伶仃洋的南部海域为研究区，基于单景高分四号卫星多光谱影像，使用梯度阈值方法对海上运动舰船进行检测，结果表明：①利用单波段高分四号多光谱影像能够检测出船位与航向，船位平均误差为80.46 m（相当于1.61个图像分辨单元），航向检出率为74.36%，航向绝对误差为8.65°。②利用单景高分四号影像能够检测出航向与船速，航向精度为98.96%，平均绝对误差为8.78°，船速精度为83.0%，平均绝对误差为1.41 m/s。研究表明高分四号卫星能够用于海上舰船近实时遥感监测，在海上舰船运动特征检测方面具有独特优势和巨大的应用潜力。

Ship Moving Feature Detection Using a Single GF⁃4 Multispectral Image

High spatial resolution geosynchronous orbit (GEO) remote sensing satellite technology can carry out repeated high-frequency monitoring over a large maritime space and will obtain the real-time dynamic features of ships on the sea surface. In this study, a single GEO satellite GF-4 (Gaofen-4) multispectral image was used to detect moving ships on the southern Lingdingyang estuary of Zhujiang in Guangdong by using the gradient threshold method. The results revealed that: (1) the ship location and direction can be detected using a single-band image from GF-4 multispectral imagery, and the average error of ship location is about 80.46 m (equivalent to 1.61 image resolution cells). The detection rate of ship direction was about 74.36%, and the absolute error of the direction was about 8.65 degrees; (2) ship speed and direction can be detected using a single GF-4 multispectral image (multi-band collaborative detection), and the accuracy of direction detection is 98.96%, and the average absolute error is 8.78 degrees. The accuracy of navigational velocity detection is 83.0%, and the average absolute error is 1.41 m/s, as verified by AIS (Automatic Identification System, AIS) data. These showed that GF-4 satellite can be used for surveillance and monitoring of ships in near real-time, and has unique advantages and great potential in dynamic changes of ships on the sea.