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DetectSingleCircle


Module: FoundationBasic

Finds the strongest circle of a given radius in the input image.

Applications

Detection of a circular or close-to-circular object like a hole, pin, pill or particle.
Name Type Range Description
inImage Image Input image
inRoi Region* Input region of interest
inRadius Real 0.0 - Circle's radius
inMinScore Real 0.0 - Minimum matching score
inEdgeThreshold Real Minimum accepted edge magnitude
outCircle HoughCircle? Found circle
diagGradientMagnitudeImage Image Visualized gradients magnitude of an input image
diagScoreImage Image Calculated score for each pixel of an input image

Description

The operation detects circular object of given radius (in pixels) in the inImage using the Hough Transform approach.

Hints

  • Connect an input image to the inImage input.
  • Define the expected circle radius on the inRadius input. Use the Ruler tool on an image preview if you are not sure.
  • Set inEdgeThreshold to define the minimum strength of edges that will be taken into account. Verify this value with the diagGradientMagnitudeImage output.
  • Experimentally set the inMinScore value, whose meaning is more or less "the number of pixels voting for a particular object location".

Examples

Description of usage of this filter can be found in examples and tutorial: Counting Saw Teeth.

DetectSingleCircle performed on the sample image.

Hardware Acceleration

This operation supports automatic parallelization for multicore and multiprocessor systems.

Complexity Level

This filter is available on Advanced Complexity Level.

Filter Group

This filter is member of DetectCircles filter group.

See Also

  • DetectLines – Finds lines in an image using Hough Transform.
  • DetectPaths – Finds a specified shape in an image using Hough Transform.
  • DetectSegments – Finds segments in an image using Hough Transform.