Spaceborne hyperspectral imaging with a static Fourier transform spectrometer
Spaceborne hyperspectral imaging with a static Fourier transform spectrometer
复制标题
使用静态傅里叶变换光谱仪进行星载高光谱成像
DOI：
10.1117/2.1201301.004601
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
J. Primot
中科院分区：
文献类型：
--
作者：
Y. Ferrec;J. Primot
高光谱成像通过测量大部分电磁频谱，一次收集和解释几十到几百个离散的频段来观察物体。许多物质留下独特的光谱特征，高光谱成像可以检测到。例如，地质学家可以使用高光谱成像来寻找石油和一些矿物。星载高光谱成像在科学和军事应用方面有着巨大的前景，如环境监测、沿海生态系统研究和城市材料测绘。然而，在大多数情况下，需要低于10m的空间分辨率目前用于民用地球观测的星载高光谱成像仪无法达到这样的分辨率（见图1）。然而，太空中的全色成像仪，可以再现人眼所见的场景，其分辨率超过1米。这种差距是由于在高光谱成像中难以达到高信噪比。改进光谱分辨率的技术减少了每个光谱带的光子数量。此外，为了收集光谱和空间信息提供的大量信息，与全色图像相比，测量高光谱图像中每个元素的可用时间减少了。时间延迟和集成技术是不可能的，并且需要大的焦平面阵列（fpa）（就像素数而言）对于这些FPA，读出时间是不可忽略的，甚至可能比积分时间更长，因为空间分辨率越细，FPA帧速率越高。因此，增加收集光子数量的策略是必不可少的。可以使用三种主要解决方案。第一种是增加瞳孔直径。然而，这种解决方案不适用于小型卫星。第二个解决方案是使用前向总线（图1）。当前和计划中的民用星载高光谱成像仪。VISNIR：可见光和近红外。SWIR：短波红外。TIR：热红外。
Hyperspectral imaging views objects by surveying a vast portion of the electromagnetic spectrum, collecting and interpreting dozens to hundreds of discrete frequency bands at a time. Many substances leave distinctive spectral signatures that hyperspectral imaging can detect. For example, geologists can use hyperspectral imaging to find oil and some minerals. Spaceborne hyperspectral imaging has great promise for scientific and military applications, such as environmental monitoring, study of coastal ecosystems, and mapping of urban materials. However, a spatial resolution lower than 10m is needed in most cases.1 Such a resolution is not reached by current spaceborne hyperspectral imagers for civilian Earth observation (see Figure 1). Yet spaceborne panchromatic imagers, which reproduce a scene as it would appear to the human eye, have a resolution better than 1m. This gap is due to the difficulty of reaching high signal-to-noise ratios in hyperspectral imaging. Techniques to refine spectral resolution decrease the number of photons per spectral band. Furthermore, in order to collect the great amount of information provided by both the spectral and the spatial information, the time available to measure each element of a hyperspectral image is reduced compared to a panchromatic image. Time delay and integration technology is impossible, and large focal plane arrays (FPAs) (large in terms of pixels) are needed.2 For these FPAs, the readout time is not negligible, and may even be longer than the integration time, all the more since the finer the spatial resolution, the higher the FPA frame rate. Thus, strategies for increasing the number of photons collected are essential. Three main solutions can be used. The first is to increase the pupil diameter. However, this solution is not adapted to small satellites. A second solution is to use a bus with a forward Figure 1. Current and planned hyperspectral civilian spaceborne hyperspectral imagers. VISNIR: Visible and near-IR. SWIR: Short-wave IR. TIR: Thermal IR.