User Guide

14 Click Close to exit the Histogram dialog box.

If you are not satisfied with the results, then you can use the AutoCAD

UNDO command to restore the image to the original settings.

Quick Reference

Image ➤ Image Processing ➤ Histogram

Raster Design Toolbar

Command Line

ihistogram

Dialog Box

Histogram Dialog Box (page 316)

Convolving an Image

Convolve uses smoothing filters (page 398) and sharpening filters (page 396) to

improve the appearance of grayscale images.

Smoothing filters reduce harshness and noise in your image. Sharpening filters

make differences in shading more distinct.

Reducing Harshness and Noise in an Image

You can use the smoothing filters (page 398) to reduce the harshness and visual

noise (page 393) in a grayscale image.

If an image contains small details that are noise rather than useful data, you

can use the smoothing filters to remove these details. For example, a smoothing

filter can improve the appearance of scans of half-toned originals.

There are two types of smoothing filters, Low Pass and Median. For more

information, see Lowpass Filtering (page 108) and Median Filter (page 106).

Raster Design uses Single Image Optimization (page 396) to speed up the editing

commands.

Convolving an Image | 105