You are here: Reference Guide > Filter Nodes > Laplacian

Laplacian

The Laplacian node takes the input image, applies a blur, and then subtracts the original from the blurred input to produce an image useful for edge detection or motion estimation. Apply different smoothing filters to the output to trade off between speed (box) and quality (gaussian).

Inputs and Controls

Connection Type	Connection Name	Function
Input	unnamed	The image sequence to which you want to apply the filter.

Control (UI)	Knob (Scripting)	Default Value	Function
Laplacian Tab
channels	channels	all	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	3	Adjusts the size of pixels within the channel defined by the channels control. Values less than 3 increase the light pixels and vice versa.
filter	filter	gaussian	Sets the filter algorithm to use: • box • triangle • quadratic • gaussian NOTE: Box is the fastest to render, whereas Gaussian blur is the smoothest.
n/a	quailty	15	Controls the level of filtering quality. Entering a low number runs the calculation more quickly, but the end result isn’t quite as smooth. The image is scaled down during the calculation, so that the blur filter is no larger than this number, and then scaled up with linear interpolation after filtering.
crop to format	crop	enabled	When enabled, crop the resulting image to the format. If the bounding box is at or inside the format, don’t enlarge it past the format. This avoids creating oversized images that you don’t need.
mask	N/A	disabled	Enables the associated mask channel to the right. Disabling this checkbox is the same as setting the channel to none.
mask	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	Blurs the edges of the mask.
mix	mix	1	Dissolves between the original image at 0 and the full effect at 1.