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Entropy of image

Started by Prateek Shrivastava June 18, 2003
Hi all,

In the calculation of the entropy of an image,
ENTROPY = - SIGMA(p log p )
j j 2 j
how can we define the parameter 'probability' for an image?

Regards,

Prateek.




You can use instead of probability, the counting of each pixel, I mean, what you need is calculate the histogram of the image. Take a look in the code below where S is the histogram.
 
N=sum(sum(S)); 
if ((N>0) & (min(S(:))>=0))
   Snz=nonzeros(S);
   H=log2(N)-sum(Snz.*log2(Snz))/N;
else
   H=0;
endPrateek Shrivastava <p...@indiatimes.com> wrote:
Hi all,

In the calculation of the entropy of an image,
ENTROPY = - SIGMA(p log p )
j j 2 j
how can we define the parameter 'probability' for an image?

Regards,

Prateek.

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