Hyperspectral imagery offers new and unique opportunities for landscape mapping. It is an offshoot of multispectral imagery, which measures reflected light in 1 to approximately 10 bands and has been an important tool in landscape mapping since deployment of Landsat in the 1970s. Both methods measure bandwidths in the infrared, visible, and ultraviolet regions of light. Compared to multispectral sensors used for most remote mapping prior to the late-1990s, however, hyperspectral sensors record narrower bandwidths and more bandwidths of reflected visible and shortwave infrared light. For example, the AVIRIS (Airborne Visible/Infra-Red Imaging Spectrometer) hyperspectral sensor records 224 different bandwidths of light between 400 and 2500 nanometers. In contrast, the Landsat multispectral Thematic Mapper records reflected light in only six bands. The narrower bandwidths of hyperspectral sensors make possible the detection of specific features that have strong reflectance in a narrow band of light (such as certain minerals). The larger number of bands enables detection of subtle differences between similar features, because the cumulative differences become large when summed over many bands.
- 词性: noun
- 行业/领域: 科学
- 类别 普通科学
- Company: McGraw-Hill
创建者
- Francisb
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