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"]
```