Using raster cleanup morphological operations

The raster cleanup commands also include several raster morphological operations: Erosion, Dilation, Opening, and Closing. These commands apply to the whole raster layer at once.

• Erosion—Decreases the thickness of all raster features in the raster layer. Features may be erased if this value is set too high.
• Dilation—Increases the thickness of all raster features in the raster layer. It can be used to add definition to features before vectorization.
• Opening—Erosion followed by Dilation using the same value. It can be used to erase thin lines, such as grid lines, in a source map before vectorization.
• Closing—Dilation followed by Erosion using the same value. It can be used to smooth rough linear features in the raster as well as fill in small gaps between raster foreground objects.

Steps:

1. Click the Raster Cleanup menu on the ArcScan toolbar and click Start Cleanup.
2. Click the morphological operation you want to perform.
3. Enter a pixel value in the dialog box.

   The operation is applied to all foreground cells with the raster layer.