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contour

The traced outer boundary of a connected region in an image.

A contour is an ordered sequence of boundary points tracing a connected region's outline -- the input every shape descriptor (perimeter, area, bounding box, convex hull, moments) is computed from. Contour approximation replaces a dense boundary trace with a small set of vertices that reproduce its shape within a specified tolerance.

Examples

  • Tracing a hand-drawn circle's outer pixels in order produces a contour that a downstream Hu-moment calculation can then summarize as seven numbers.

See also

convex hull bounding box contour approximation
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