Houdini 22.0 Nodes Copernicus nodes

Laplacian Copernicus node

Computes the Laplacian of a layer.

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Since 22.0

This node computes the Laplacian of the source layer. This output is the sum of the second derivatives along the layer’s width and height.

For example, use this node to detect edges.

Parameters

Signature

The layer type that the source accepts.

See Signatures for more information.

Space

The space in which to compute the Laplacian. This affects the magnitude of the result.

Image

Compute the Laplacian in image space. This normalizes the change in values by the image-space pixel size.

Pixel

Compute the Laplacian in pixel space. This normalizes the change in values by the pixel size.

Local

Compute the Laplacian in local space. This normalizes the change in values by the world-space pixel size.

Scale

The amount by which to multiply the source values before the node computes the Laplacian.

Read Pixels outside Image

Makes derivatives at the boundary read pixels outside of the image. When off, derivatives at the boundary read pixels within the image range.

Turning this parameter on is useful when building seamless textures with a Wrap border type. Turn this off when you want to avoid artificial flattening of the derivative at the boundary in a Clamp border type, as it acts like an extrapolation.

Kernel Size

The maximum distance (in buffer elements) of the pixels to use to compute the derivatives for the Laplacian.

A derivative is often computed with adjacent pixels, but if the values are slowly varying there may not be enough bit-depth to get smooth derivatives. Increasing this value may remove stepping artifacts from the result.

Inputs

source

The layer from which to compute the Laplacian.

Outputs

laplacian

The computed Laplacian. For multi-channel inputs, the node computes the Laplacian for each channel.

See also

Copernicus nodes