This research introduces a novel oblique longwave infrared (LWIR) atmospheric compensation (AC) technique for hyperspectral imagery, oblique in-scene AC (OISAC). Current AC algorithms have been developed for nadir-viewing geometries, which assume that every pixel in the scene is affected by the atmosphere in nearly the same manner. However, this assumption is violated in oblique imaging conditions where the transmission and path radiance vary continuously as a function of object-sensor range, negatively impacting current algorithms’ ability to compensate for the atmosphere. The technique presented here leverages the changing viewing conditions to improve rather than hinder AC performance. An initial analysis of OISAC’s ability to perform AC for both synthetic and measured hyperspectral images suggests improved performance in oblique-viewing conditions compared with standard techniques. OISAC is an extension of ISAC, a technique that has been used extensively for LWIR AC applications for over 20 years. OISAC has been developed to incorporate the range dependence of atmospheric transmission and path radiance in identification of the atmospheric state. Similar to the full implementation of ISAC, OISAC requires the existence of near-blackbody-like materials over the 11.73- $\mu \text{m}$ water band.

中文翻译：

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斜向现场大气补偿

本研究介绍了一种用于高光谱图像的新型倾斜长波红外 (LWIR) 大气补偿 (AC) 技术，即倾斜现场 AC (OISAC)。当前的 AC 算法已经开发用于天底观察几何，假设场景中的每个像素都以几乎相同的方式受到大气的影响。然而，这种假设在倾斜成像条件下被违反，其中传输和路径辐射作为物体传感器范围的函数连续变化，对当前算法补偿大气的能力产生负面影响。这里介绍的技术利用不断变化的观看条件来改善而不是阻碍 AC 性能。对 OISAC 对合成和测量的高光谱图像执行 AC 能力的初步分析表明，与标准技术相比，斜视条件下的性能有所提高。OISAC 是 ISAC 的扩展，该技术已广泛用于 LWIR AC 应用 20 多年。OISAC 已被开发用于将大气传输和路径辐射的距离依赖性纳入大气状态的识别。与 ISAC 的完全实现类似，OISAC 要求在 11.73- 上存在近黑体类材料 OISAC 已被开发用于将大气传输和路径辐射的距离依赖性纳入大气状态的识别。与 ISAC 的完全实现类似，OISAC 要求在 11.73- 上存在近黑体类材料 OISAC 已被开发用于将大气传输和路径辐射的距离依赖性纳入大气状态的识别。与 ISAC 的完全实现类似，OISAC 要求在 11.73- 上存在近黑体类材料 $\mu \text{m}$水带。