OMNIVIS project 2009
Filters Mathematica
OMNIVIS: Omni-directional Vision
Office: SciCtr 434


Mathematica

Mathematica 7 has quite many image manipulation features.


A = Import["leman.jpg"]; w=Length[A[[1,1]]]; h=Length[A[[1]]]; 
B = ColorNegate[ImageMultiply[LaplacianFilter[A, 1], 1]];
Export["leman1.jpg",Show[B],"JPG",ImageSize->{w,h}];
What does the Laplacian Filter do? Here is an experiment: (you have to run this in a Mathematica notebook. For reasons which do not make sense, Mathematica does not render this when run without a notebook):
A = Table[k+l, {k,10},{l,10}]; 
S = GraphicsArray[ Table[ListDensityPlot[LaplacianFilter[A, k], 
    ColorFunction -> Hue, Frame -> False, Axes -> False], {k, 1, 5}]];
Export["laplacians.jpg",S,"JPG",ImageSize->{500,100}];
It is not the standard Laplacien as one can see when runnning it on a general matrix:
LaplacianFilter[{{a, b, c}, {d, e, f}, {g, h, i}}, 1]
The multiplication is illustrated as follows:
A = Import["leman.jpg"]; B = Dilation[A,3]; 
Export["multiply.jpg",Show[ImageMultiply[A,B]],"JPG"]


Questions and comments to knill@math.harvard.edu
Oliver Knill | Department of Mathematics | Harvard University