How to detect edges in an image?

Select your file and the Sobel edge detection is applied automatically, highlighting edges as bright lines on a dark background.

What is Sobel edge detection?

A classic computer vision technique that highlights edges by computing the gradient of pixel intensity changes across the image.

What is Sobel edge detection used for?

Research, computer vision experiments, stylized line-art effects, and identifying structural features in images.

What file formats can I export?

You can export as PNG, JPEG, WebP, TIFF, BMP, or HEIC.

Is this tool free to use?

Yes — completely free, no account needed. Your images are processed entirely in your browser and never uploaded to a server. Downloads have no watermarks.

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Apply Sobel Edge Detection to Image Online

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What you can expect

Interactive, browser-based Sobel edge detection demo for research and experimentation. Upload images to visualize gradient-based edge detection in real time—ideal for learning, prototyping, and exploring computer vision concepts directly in the browser.

Related tools

More BrushCue tools that fit this workflow.

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Sharpen

Sharpen your images instantly with this browser-based sharpening tool. Enhance edges, boost clarity, and bring out fine details to make photos look crisp and focused. Adjust the strength to control how subtle or intense the sharpening effect appears, whether you’re refining portraits, improving product shots, or restoring slightly soft images—all without leaving your browser.

Color Threshold

This tool compares the linear R, G and B components of an image. If any item is below the threshold, it returns black. Otherwise, it returns white. Useful in computer vision tasks and stylistic effects.

Lightness Threshold

Applies a threshold to the OkLab L (lightness) component, analogous to how Color Threshold operates on individual RGB channels. This tool converts continuous tonal values into hard transitions, producing a stark, high-contrast, etching-like effect that emphasizes form and structure.

Median Filter

Runs a median filter over the composition. This will accumulate the R, G and B components of your image and then calculate the median of each component. Valid range for the kernel size is between 1 and 5. Use this tool to remove noise from an image.

Dilate

The dilate tool performs a dilation, also known as a morphological max, on your image. Select your image and select the dimension.

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Online Scientific Image Processing Tools

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Frequently asked questions

How to detect edges in an image?: Select your file and the Sobel edge detection is applied automatically, highlighting edges as bright lines on a dark background.
What is Sobel edge detection?: A classic computer vision technique that highlights edges by computing the gradient of pixel intensity changes across the image.
What is Sobel edge detection used for?: Research, computer vision experiments, stylized line-art effects, and identifying structural features in images.
What file formats can I export?: You can export as PNG, JPEG, WebP, TIFF, BMP, or HEIC.
Is this tool free to use?: Yes — completely free, no account needed. Your images are processed entirely in your browser and never uploaded to a server. Downloads have no watermarks.

For developers

Use Sobel Edge Detection from Python

Open the Jupyter notebook example to see how to run this tool from the BrushCue Python API, inspect the processing steps, and adapt the workflow for scripts or batch image jobs.

View Python notebook

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