Erode (filter)

Filters input pixels relative to the size control, and is particularly useful with mattes. Negative values cause brighter areas to expand into darker areas and positive values cause darker areas to expand into lighter areas. Use the filter dropdown to control the erode computation speed (box) versus quality (gaussian).

Erode (filter) is similar to Erode (fast), but can be computationally more expensive because you can select the filter type to improve the erode quality.

Inputs and Controls

Connection Type

Connection Name

Function

Input

unnamed

The image or matte to erode.

Control (UI)

Knob (Scripting)

Default Value

Function

FilterErode Tab

channels

channels

none

The effect is only applied to these channels.

If you set this to something other than all or none, you can use the checkboxes on the right to select individual channels.

size

size

1

Adjusts the size of pixels within the channel defined by the channels control. Values less than 1 increase the light pixels and vice versa.

filter

filter

box

Select the filter algorithm to use:

box

triangle

quadratic

gaussian

Note:  Box is the fastest to render, whereas Gaussian blur is the smoothest.

mask

N/A

disabled

Enables the associated mask channel to the right. Disabling this checkbox is the same as setting the channel to none.

maskChannelInput

none

The channel to use as a mask. By default, the effect is limited to the non-black areas of this channel.

inject

inject

disabled

Copies the mask input to the predefined mask.a channel. Injecting the mask allows you to use the same mask further downstream.

invert

invert_mask

disabled

Inverts the use of the mask channel, so that the effect is limited to the non-white areas of the mask.

fringe

fringe

disabled

When enabled, only apply the effect to the edge of the mask.

When disabled, the effect is applied to the entire mask.

mix

mix

1

Dissolves between the original image at 0 and the full effect at 1.