Autotek autocad raster design 2010 Benutzerhandbuch

Raster Design uses the following lowpass filters:

■

Lowpass Filter #1 averages differences between the target pixel value and
its side to side and top and bottom neighbors. Diagonally adjacent pixels
are ignored.

■

Lowpass Filter #2 evenly weighs all pixels in the kernel including the target.

■

Lowpass Filter #3 evenly weighs all pixels surrounding the target while
providing extra weight to the target pixel. This tends to reduce the blurring
effect to the image.

■

Lowpass Filter #4 heavily weighs the target pixel while weighing adjacent
side to side and top and bottom pixels more heavily than diagonally
connected pixels. Heavy weighting on the target pixel tends to reduce
blurring effects and less weighting on the diagonal pixels acknowledges
that their centers are further away than side adjacent pixels.

■

Blurring evenly weighs all pixels in the kernel including the target. This
filter, while similar to Lowpass Filter #2, gives slightly brighter results.

On a low resolution scan, you can also use the 

 (page 396) to

make differences in shading more distinct and enhance edges in the image.
For more information on sharpening filters, see 

 (page 109) and

 (page 110).

 (page 396) to speed up the editing

commands.

Highpass filters can enhance the edges and sharpen details in a grayscale
image.

Raster Design uses the following highpass filters:

■

Highpass Filter #1 picks up differences between the target pixel and its
neighbor's side to side and top and bottom. Diagonally connected pixels
are ignored.

■

Highpass Filter #2 evenly weighs all the surrounding pixels in the kernel
but places an especially high weight is on the target pixel. Thus, if the
target pixel differs significantly from its neighbors, the dimming effect of
the neighboring pixels negligible.

Convolving an Image | 109