Edge detection (Sobel)

Extract the edges of an image using the Sobel operator, a classic image processing algorithm.

Example:

How it works

Preparing an image for automated processing, a stencil, or simply after a "line drawing" artistic effect? The tool first converts the image to grayscale, then computes a horizontal and vertical intensity gradient at each pixel (Sobel operator) to locate areas of high contrast, which correspond to edges.

Why is the result in black and white?

The Sobel operator works on the image's brightness, not its colors. The result is a "gradient magnitude" map: the lighter a pixel, the more it lies on a strong edge; uniform areas stay black.

Is the result always in PNG format?

Yes, regardless of the original image's format (JPEG, WebP, etc.), the edge map is always produced as a PNG, a lossless format suited to grayscale images.

100% local processing: the detection is performed in your browser via our WebAssembly module — your images are never sent to a server.