Erode / Dilate Node

The Erode/Dilate node will erode or dilate edges in an image, as you specify. Any or all channels can be adjusted, but Erode/Dilate is used primarily to modify matte edges for better composites.

Note:
If you want to modify the edges of an Ultimatte matte in an "over" composite, use the Ultimatte AdvantEdge node, which is described in chapter 15, "Composite Nodes ," rather than Erode/Dilate.

The Erode/Dilate node accepts one or two inputs. The optional second input is used for a control image (the output of an Edge node, for example) for the effect.

Erode / Dilate Parameter Tab

Operation

The Operation popup menu enables you to select Erode or Dilate for the operation.

Magnitude

The Magnitude parameter controls the size of the erode or dilate effect. The Magnitude value is expressed as a percentage of the total width of the input image. The range is 0-1.

Softness

The Softness parameter uses subpixel accuracy to modify the softness, or falloff, of the effect in a range of 0-1. When the Softness parameter is set at 0, the original edge pixel values are used to erode or dilate the edge by the specified Magnitude value.

Nonzero Softness values, however, will gradate the pixel values from the original edge inward (for erode) or outward (for dilate) to the new edge. The greater the Softness value, the steeper the slope, or falloff. A Softness value of 1 produces a circular gradient from the original edge to the new edge.

Channel Mask

The Channel Mask parameter enables you to inhibit the modification of any channel by deselecting the Red, Green, Blue, Alpha, or Other channel icons.

Control Image Parameters

The Control Action and Control Channel menus enable you to specify how an optional control image input will govern the node operation, as explained in "Using Control Images with Filter Nodes ."




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