This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.1)

EntropyFilter

EntropyFilter
filters image by replacing every value by the information entropy of the values in its range r neighborhood.
EntropyFilter
applies entropy filtering to an array of data.
  • EntropyFilter computes the information entropy of the values in blocks centered on each pixel.
  • Given a set of values , the information entropy is taken to be .
  • For multichannel images, EntropyFilter computes the local entropy of the set of pixel vectors.
  • At the edges of an image, EntropyFilter uses smaller neighborhoods.
  • EntropyFilter uses neighborhoods with vertical range and horizontal range .
  • In EntropyFilter, data can be an array of any rank, and can contain symbolic as well as numerical entries.
Entropy filtering of random disks:
Apply entropy filtering to show areas of higher information content with higher intensities:
Apply an entropy filter to a vector of numbers:
Entropy filtering of random disks:
In[1]:=
Click for copyable input
In[2]:=
Click for copyable input
 
Apply entropy filtering to show areas of higher information content with higher intensities:
In[1]:=
Click for copyable input
Out[1]=
 
Apply an entropy filter to a vector of numbers:
In[1]:=
Click for copyable input
Out[1]=
Entropy filtering can reveal JPEG compression artifacts:
This reveals the presence of padding in an image:
New in 7