Autotek autocad raster design 2010 用户手册

■

Enter w and then draw a window around any group or groups of
speckles that you want to keep.

■

Enter p and then draw a polygon around a group of speckles that you
want to keep.

■

Enter r and then repeat step 4 to respecify the speckle size and see a
different set of speckles highlighted for deletion.

Menu

Image  ➤  Cleanup  ➤  Despeckle

Raster Design Toolbar

Command Line

idespeckle

You can use the Bias tool to correct distortions in the aspect ratio of an image.

Normally, this ratio is maintained when scaling an image in AutoCAD.
However, if the image is distorted due to paper shrinkage or optical distortions
in the scanning process, the Bias tool can correct the aspect ratio by resizing
the image in one or two dimensions, using either existing vector geometry or
a distance you specify.

When you use the Bias tool, Raster Design prompts you to enter calibration
(existing) distances and desired distances in the X and Y directions. The
application stretches or shrinks the entire image to correspond to the ratio of
the distances you specified. The X and Y directions are relative to the image
and not its position in the drawing. In each case, you can select two points
(or enter a distance) to specify the calibration distance, then select two
corresponding points (or enter a new distance) to specify the desired distance.
You can also use existing geometry to define the desired distance; for instance,
by selecting the endpoints of a line.

86 | Chapter 6   Modifying Images