| Maximum likelihood question (ENVI) [message #37607] |
Wed, 07 January 2004 20:01 |
Jonathan Greenberg
Messages: 91
Registered: November 2002
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I'm trying to generate images of true probabilities from maximum likelihood
rule images. Since the final probability rule images were modified (from the
RSI website): "In the ENVI 3.6 implementation, the rule images (one per
class) contain a maximum likelihood discriminant function with a modified
Chi Squared probability distribution.", I am unclear as to how to get BACK
to true probabilities. Typing in the % probability into the rule classifier
doesn't really get me what I need. Could I get the "true" probability for a
given class (let's say we have two classes, A and B) and calculating:
Rule image A/(rule image A + rule image B) ?
Or is there some other technique I need to perform to get a true probability
image? Thanks!
I'm planning on using this in combination with Bayesian logic tools, which
is why I need, for each pixel and for each class the posterior probability
(0 to 1). As I mentioned, the rule classifier is only good if I want to
perform a new classification based on the rule images, not if I want to see
directly what these probabilities are.
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