Contour Detection
Detect image contours and outline closed shapes, regions, and object boundaries for segmentation and computer vision debugging.
Identify and draw contours around objects in any image. Useful for shape analysis, object counting, and boundary visualization.
How to Use Contour Detection
- Upload an image: Upload one of the formats listed by the tool (JPG, PNG, WebP) and wait for the local preview.
- Adjust settings and process: Adjust the binary threshold and minimum area to control which contours are detected and drawn.
- Review and download: Review the result, then download it in one of the formats offered by this tool.
Frequently asked questions
What is contour detection?
Contour detection finds continuous curves that form the boundaries of objects in an image. It is used in shape analysis, object counting, gesture recognition, and industrial inspection.
What is the difference between external and all contours?
External mode detects only outermost contours (no nested boundaries). All mode returns every contour including holes. Tree mode preserves the parent-child hierarchy.
What is the difference between contours and edges?
Edges are pixels where intensity changes sharply. Contours are closed curves that form the boundary of a shape, extracted by connecting edge pixels. Contour detection finds these connected boundaries, enabling shape analysis, area measurement, and object counting.
Is the Contour Detection tool free?
Yes. All tools on Pixlane are free with no signup required.
Does it reuse cached assets on repeat visits?
Browser caching can speed repeat visits; uncached site assets can still require an internet connection.
What image formats are supported?
JPG, PNG, and WebP are supported.
What is the minimum contour area filter used for?
The minimum area filter removes small, noisy contours below a pixel-area threshold. This cleans up results by keeping only significant shapes and ignoring noise artifacts from thresholding.
What are convex hulls and bounding boxes in contour analysis?
A bounding box is the smallest axis-aligned rectangle enclosing a contour. A convex hull is the tightest convex polygon around the contour, helpful for shape analysis and detecting concavities or protrusions.