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Last Post 28 Dec 2006 08:14 PM by  anon
Minnaert correction
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anon



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28 Dec 2006 08:14 PM
    How can I do Minnaert correction, one of topographic corrections, in ENVI? Are there any routines or should I make a IDL code?

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    28 Dec 2006 08:14 PM
    To perform a Minnaert correction in ENVI, you will need to implement the algorithm using a custom-built IDL program. I do not know of one that already exists. The most straightforward discussion of the algorithm I have found is this article: http://www.isprs.org/ista...comm3/papers/347.pdf Minnaert correction is discussed on page 2. The algorithm requires that the input data be in radiance. It also requires that you know both incident angle and slope angle for each pixel. It ends up looking something like this: log (L*cos e) = log (Ln) + k*log (cos i*cos e) where: L = radiance e = slope angle i = incident angle Ln = radiance for a Lambertian surface (i=0) k = Minnaert constant (value between 0 and 1) It also can be written this way: Ln = L*(cos e)/((cos^k i) * (cos^k e)) You should be able to derive both e and i for your scene using a DEM and knowledge about the look angle of the sensor that produced the data you want to correct. Deriving k requires the use of linear regression, for which IDL has many routines to choose from.

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    28 Dec 2006 08:14 PM
    Hi Seung & Devin.... I Have a question about the Minnaert Correction with ENVI 4.3, but my license is without IDL.. Can I calculate Minnaert Correction only band math? How can I calculate the regression linear with scatter plot? Thank you Happy new year!!!!!!!!!!!!!! Regards
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