I. Introduction
Infrared (IR) images have a wide range of applications in military and civilian domains [1]. Out of the imaging principle, which is based on temperature characteristics of objects, the imaging environment is not limited by weather or illumination conditions. In recent years, IR imaging has been utilized in maritime surveillance including ship detection, segmentation, and recognition [2], [3]. This makes the applications of an IR imaging technique have great military significance. IR ship segmentation is a key step of target recognition and analysis, whose results would exert a remarkable effect on the accuracy of downstream processes. Generally, a precise segmentation result of the ship target would contribute a lot to improving the accuracy rate of identification. However, it is difficult to obtain an accurate segmentation result due to the restriction of properties of IR images. Uneven heat dissipation leads to an uneven intensity distribution of targets [4]. Blurring edge is also a common phenomenon in IR images, which results in a low resolution along with losing texture details. Besides, there would be a complex background containing mist, surface reflection, and nonship objects with high intensity [5]. For these reasons, IR ship segmentation is still a challenging task.