Negative Values in Linear Unmixing - NV5 Geospatial

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Last Post 01 Dec 2010 12:50 PM by anon

Negative Values in Linear Unmixing

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anon

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01 Dec 2010 12:50 PM
Hi, I keep getting too many negative values (60% of pixels) when preforming linear unmixing. In other words, a pixel will have -25% green vegetation. Applying gains to my "pure" spectra helps, but doesn't alleviate the problem. What do these negative numbers mean exactly? Thanks!

MariM

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01 Dec 2010 01:28 PM
The ENVI help discusses this: If many pixels have values above 1.0 or below 0.0, this indicates that one or more of the endmembers chosen for the analysis are probably not well-characterized, or that one or more additional endmembers are missing from the analysis. If you have more in-depth questions about this, you might want to contact ITT Technical Support directly.

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