Edge Detect

Overview

Extracts abrupt changes in an image as white lines. Use it as the basis for an outline, a boundary mask, a glowing edge, or surface-relief effects.

Select with mode whether to detect changes in brightness, boundaries in alpha, or changes in the colors themselves.

Usage tips

• Choosing mode is the key: use Alpha for a shape's outline (the boundary with transparency), or OKLCH-L for light-dark boundaries inside the artwork. When unsure, start with Alpha.
• The output is not a line image but a map of boundary strength. To use it as a line, remove noise with threshold and layer it with blend, or pass it as a mask to a color-adjustment node.
• strength accepts 0–8 and threshold accepts 0–1. Values promoted from input ports outside those ranges are clamped, with a warning shown on the parameter.
• For a character silhouette, the dedicated outline node is more direct. Use Edge Detect when you also want to capture boundaries inside the image.

Related nodes

• outline — dedicated silhouette-outline node
• blend — layer the detected lines
• morphology — thicken and clean up the detected result
• region_border — RegionMap-based boundaries

Examples

• Use Alpha to extract the boundary with transparent areas as the basis for an outline.
• Use OKLCH-L to turn only light-dark boundaries into white lines.
• Raise threshold to remove fine grain and retain only strong outlines.
• For tile assets, enable wrap_x / wrap_y so edge detection includes continuity across the left/right and top/bottom edges.