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Allegato alla nota 82 del 19990102

2.1.1 2D-Dithering

For a 2D-Dithering I used Floyd Steinberg Dithering, but it is possible to make some experiments with Ordered Dithering or similar method. Floyd-Steinberg Dithering and 3D-Dithering have one important feature: precious error distribution.
If original voxel intensity is I(x,y) and dithered voxel intensity of the same voxel is I_d(x,y) , we can defined, that
ERROR = I(x,y) - I_d(x,y).
On the image is the one possibility of distribution of this error information.

Error diffusion in Floyd-Steinberg Dithering

This possibility of error diffusion we can describe via this equations:

2.1.2 2D-UnDithering

2D-Undithering is inverse process for Dithering. This Process we can implement using convolution [2], [3].
A is convolutory matrix with size (m,n). But almost m and n are odd integers. Undithered intensity I_ud(x, y) we can describe from dithered intensity I(x, y) as:

Matrix A is an normal convolutory matrix. With good result I used these matrixes: