[Keith Vetter] 2006-07-22 : is a technique used in 
computer graphics to create the illusion of color 
depth in images with a limited color palette (color 
quantization). In a dithered image, colors not 
available in the palette are approximated by a 
diffusion of colored pixels from within the 
available palette. [http://en.wikipedia.org/wiki/Dither]

Here some code that implemenents some dithering 
algorithms, along with the requisite demo code.
The code here is only for gray-scaled images
but could easily be extended to color images. 
Also, another improvement would be to use
an optimized paletter before dithering
(see [Reduce Colour Depth - Median Cut]).

This was a really fun project. To save space
in the wiki, I didn't include a sample image
in the demo. Instead, I tried linking to 
tcl demo images and images from the web
(I included some famous image processing images
such as Lena).

For fun, try out some of the various web images I 
included links for and see a) how many colors are
needed by the various algorithms to look good, and
b) how badly some algorithms are with certain images
at different color depths.

For example, try the tcl demo code image of the teapot
at just 2 colors and then 3 colors.

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[Category Graphics] |
[Category Image Processing] |
[Category Algorithm]