不同条件下海面Kelvin尾迹的红外仿真

Infrared simulation of Kelvin wake on sea surface under different conditions

针对舰船在海上航行时形成的尾迹包含多类信息,利用Kelvin尾迹模型得到舰船速度为5m/s、10m/s和15m/s的尾迹最大波高分别为0.5m、1.5m和2.5m。通过海浪PiersonMoscowitz谱模型描述海面风速分别为5m/s、8m/s和10m/s下的复杂海面背景模型。基于海面背景和尾迹区域的几何差异,建立了Kelvin尾迹的红外发射模型,得到不同海面风速、不同舰船航速和不同探测天顶角下的红外特征仿真图像。仿真结果表明,红外图像的灰度极大值位于尾迹波峰处,海面风速由5m/s增加到10m/s时,尾迹区域与海面背景平均灰度差值由100逐渐减小,直至无差异。相同海面风速下,舰船速度由5m/s增加到15m/s,尾迹波长由10m增加到40m,红外特征明显。改变探测器天顶角分别为0°和30°时,红外图像差异较小,当天顶角增大到60°时,尾迹区域灰度值接近海面背景,差值小于30,尾迹的辨识难度增加。

The wakes generated by ships on the sea contain a wide range of information.We applied the Kelvin wake model and obtained the wake maximum wave height of 0.5m,1.5mand2.5m,respectively,corresponding to the warship's velocity of 5m/s,10m/s and 15m/s.We described the complex sea backgrounds with different wind speeds of 5m/s,8m/s and 10m/s by the Pierson-Moscowitz sea spectrum model.The infrared emission model of the wake on the sea was established by geometry differences of the wake and the background,and infrared images were got in different speeds of the sea wind,different speeds of the ship and different detection angles of the detector.The simulation results show that the maximum gray value of infrared image is at the wake wave peak,and when the wind speed increases from 5m/s to 10m/s,the average gray difference between the wake area and sea surface background gradually reduces from 100,until no difference.Under the same sea surface wind speed,the wake wave-length increases from 10 mto 40m with the ship speed increasing from 5m/s to 15m/s,and the infrared feature is obvious.The infrared image difference is insignificant when the detector zenith angle is 0°and 30°.When the zenith angle increases to 60°,the wake region gray scale is closed to the sea background gray scale,the difference value is less than 30,so it becomes more difficult to recognize targets.