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.