双波段航空遥感相机的目标作用距离

Target operating range of dual band aerial remote camera

为解决航空遥感相机不同波段目标作用距离计算模型缺乏统一评价标准及工程闭环等问题,开展双波段航空遥感相机目标作用距离评价标准研究及工程应用案例分析。明确航空遥感相机目标作用距离的限制条件,从目标的几何和辐射特性出发。首先根据航空遥感的特点提出了目标三维投影变换关系式,得到任意观测工况下目标的等效观测尺寸;针对可见光、红外双波段点目标和面目标各自不同的辐射成像特点,分别建立了目标作用距离计算模型。接着,结合工程应用示例对不同计算模型的结果进行分析比较,给出了适合航空遥感相机远距离斜视成像条件下选用的计算模型。然后,采用某型航空遥感相机的实际飞行图像中提取的信息,对目标作用距离计算过程中信噪比及调制度的阈值进行了合理选择,并根据修正后的阈值分析了大型舰船和坦克在可见光与红外不同的探测及识别概率下对应的作用距离。分析结果表明:在载机航高18 km,大气能见度15 km,航空遥感相机可见光焦距不低于1.5 m时,可实现在50%的概率下对海面大型舰船的探测距离141 km、识别距离93 km,对陆地坦克等小目标的探测距离105 km、识别距离80 km;在红外焦距不低于1 m的条件下,可实现在50%的概率下对海面大型舰船的探测距离203 km、识别距离140 km,对陆地坦克等小目标的探测距离44 km、识别距离37 km。上述仿真的结果吻合实际,本文的成果可较好应用于工程实践。

In order to solve the problem of lack of unified evaluation standard and engineering closed-loop for target operating distance calculation model of aerial remote sensing camera in different bands,the research on target operating distance evaluation standard of dual band aerial remote sensing camera and engineering application case analysis were carried out.Firstly,according to the characteristics of aerial remote sensing,the three-dimensional projection transformation relationship of the target is proposed to obtain the equivalent observation size of the target under any observation condition;According to the different radiation imaging characteristics of visible and infrared dual band point target and area target,the target operating range calculation models are established respectively.Then,combined with an engineering application example,the results of different calculation models are analyzed and compared,and the calculation model suitable for long-range squint imaging of aerial remote sensing camera is given.Then,the information extracted from the actual flight image of an aerial remote sensing camera is used to reasonably select the signal to noise ratio(SNR)and modulation threshold in the calculation process of target operating distance,According to the modified threshold,the corresponding operating distance of large ships and tanks under different detection and recognition probabilities of visible light and infrared is analyzed.The analysis results show that when the flight height of the carrier is 18 km,the atmospheric visibility is 15 km and the visible light focal length of the aerial remote sensing camera is not less than 1.5 m,the detection distance of 141 km and 93 km for large ships on the sea and 105 km and 80 km for small targets such as land tanks can be realized with 50%probability;Under the condition that the infrared focal length is not less than 1m,the detection distance of 203 km and the recognition distance of 140 km for large ships on the sea and 44 km and 37 km for small targets such as land tanks can be realized with a 50%probability.The above simulation results are consistent with the reality,and the results of this paper can be better applied to engineering practice.