Thompson David R, Boardman Joseph W, Eastwood Michael L, Green Robert O
Opt Express. 2017 Apr 17;25(8):9186-9195. doi: 10.1364/OE.25.009186.
The intrinsic spectral dimensionality indicates the observable degrees of freedom in Earth's solar-reflected light field, quantifying the diversity of spectral content accessible by visible and infrared remote sensing. The solar-reflected regime spans the 0.38 - 2.5 μm interval, and is captured by a wide range of current and planned instruments on both airborne and orbital platforms. To date there has been no systematic study of its spectral dimensionality as a function of space, time, and land cover. Here we report a multi-site, multi-year statistical survey by NASA's "Classic" Airborne Visible Near InfraRed Spectrometer (AVIRIS-C). AVIRIS-C measured large regions of California, USA, spanning wide latitudinal and elevation gradients containing all canonical MODIS land cover types. The spectral uniformity of the AVIRIS-C design enabled consistent in-scene assessment of measurement noise across acquisitions. The estimated dimensionality as a function of cover type ranged from the low 20s to the high 40s, and was approximately 50 for the combined dataset. This result indicates the high diversity of physical processes distinguishable by imaging spectrometers like AVIRIS-C for one region of the Earth.
固有光谱维度指示了地球太阳反射光场中可观测的自由度，量化了可见光和红外遥感可获取的光谱内容的多样性。太阳反射波段跨越0.38 - 2.5μm区间，被机载和轨道平台上的一系列现有及计划中的仪器所捕捉。迄今为止，尚未有关于其光谱维度作为空间、时间和土地覆盖函数的系统研究。在此，我们报告了美国国家航空航天局（NASA）的“经典”机载可见近红外光谱仪（AVIRIS-C）进行的一项多站点、多年度的统计调查。AVIRIS-C测量了美国加利福尼亚州的大片区域，跨越了广泛的纬度和海拔梯度，涵盖了所有典型的中分辨率成像光谱仪（MODIS）土地覆盖类型。AVIRIS-C设计的光谱均匀性使得能够在不同采集过程中对测量噪声进行一致的场景内评估。根据覆盖类型估计的维度范围从20年代低到40年代高，综合数据集的维度约为50。这一结果表明，像AVIRIS-C这样的成像光谱仪在地球的一个区域能够区分出高度多样的物理过程。
