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Spectral ratio method for measuring emissivity

Remote Sensing of Environment

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Abstract

The spectral ratio method is based on the concept that although the spectral radiances are very sensitive to small changes in temperature the ratios are not. Only an approximate estimate of temperature is required thus, for example, we can determine the emissivity ratio to an accuracy of 1% with a temperature estimate that is only accurate to 12.5 K. Selecting the maximum value of the channel brightness temperatures is an unbiased estimate. Laboratory and field spectral data are easily converted into spectral ratio plots. The ratio method is limited by system signal:noise and spectral band-width. The images can appear quite noisy because ratios enhance high frequencies and may require spatial filtering. Atmospheric effects tend to rescale the ratios and require using an atmospheric model or a calibration site. ?? 1992.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Spectral ratio method for measuring emissivity
Series title:
Remote Sensing of Environment
Volume
42
Issue:
2
Year Published:
1992
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
113
Last page:
116
Number of Pages:
4