Automatic detection of ships in RADARSAT-1 SAR imagery

NOAA/NESDIS has initiated a program called the Alaska SAR Demonstration with the goal of demonstrating the utility of RADARSAT-1 C-band SAR imagery to provide useful, timely environmental and resource management information to users in Alaska. One product generated under the program is a list of ship locations. This paper describes the algorithm developed to generate this product by automatically detecting ships based on changes in the local statistics. Using low resolution imagery (100 metres sample spacing) it is shown that ships of lengths greater than 35 metres can be detected (representing 105 ships out of a total of 272 in the test set) with a false alarm rate of 0.01% for a single detection. With high-resolution imagery (50 metres sample spacing) ships of lengths greater than 32 metres can be detected (representing 124 ships out of 272) with a false alarm rate of 0.002% for a single detection. The algorithm is completely automated and takes approximately 10 minutes of elapsed time to run on a ScanSAR Wide B Mode image.