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entropy

$ \bigcirc$Name


entropy Compute the entropy given by an histogram




$ \bigcirc$Command Synopsis


entropy Histo .



Histo : Input histogram (fsignal)

. (screen output) :




$ \bigcirc$Function Summary


void entropy (Histo , Entropy )

Fsignal Histo ;

double *Entropy ;




$ \bigcirc$Description


This module computes the Shannon entropy of the input histogram. If {sk}1 $\scriptstyle \leq$ k $\scriptstyle \leq$ K are the values of the input fsignal, then entropy computes

- $\displaystyle \sum_{{k=1}}^{K}$$\displaystyle \tilde{{s}}_{k}^{}$log$\displaystyle \tilde{{s}}_{k}^{}$

where $ \tilde{{s}}_{k}^{}$ = sk/($ \sum_{{l=1}}^{K}$sl). It is assumed that the sk's are positive.




$ \bigcirc$See Also


fscalq, fvq.


$ \bigcirc$Version 1.0


Last Modification date : Thu Nov 29 20:23:56 2001


$ \bigcirc$Author


Jean-Pierre D'Ales







mw 2004-05-05